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Porocarcinomas are rare sweat gland cancers representing the malignant counterpart to benign poromas. Their diagnosis can be challenging, especially in the absence of an associated poroma or when the tumor is poorly differentiated. Since recurrent YAP1::MAML2 and YAP1::NUTM1 fusions have been identified in poroid tumors, molecular studies provide an opportunity to support the diagnosis in challenging cases. We describe a case of a female patient in her early 90s, with a polypoid mass of the hip. Histopathologically, there was a poorly differentiated malignant spindle cell tumor adjacent to a poroma. Because of the close association with a poroma and immunoreactivity for p40, a diagnosis of spindle cell porocarcinoma was rendered, which was further supported by YAP1 immunohistochemical studies. Antibodies targeting both the N‐terminus and C‐terminus confirmed YAP1 rearrangement in both the poroma and the spindle cell neoplasm. Subsequent targeted RNA sequencing revealed a YAP1::MAML3 gene fusion. MAML3 has previously not yet been reported as a YAP1 fusion partner in porocarcinoma. With the illustration of a rare spindle cell variant of porocarcinoma and the identification of a novel gene fusion, this case report expands the spectrum of morphologic and genomic aberrations associated with porocarcinoma. [ABSTRACT FROM AUTHOR]

Spitz tumours comprise a spectrum of melanocytic proliferations that share a set of distinct cytological features and molecular pathways. They include benign naevi, intermediate or indeterminate tumours and rare melanomas. Spitz tumours are notorious for the difficulty of distinguishing benign neoplasms with atypical features from melanomas and the related diagnostic uncertainty. Advances in the knowledge of the molecular pathways and genomic aberrations associated with these neoplasms have permitted opportunities for a reduction in the number of uncertain diagnoses and a more objective distinction between Spitz tumours from Spitz‐like neoplasms. The presence of a Spitz molecular pathway, such as Harvey rat sarcoma viral oncogene homologue (HRAS) aberrations or kinase fusions, distinguishes a bona fide Spitz neoplasm from Spitz‐like naevi or melanomas with conventional driver mutations. Spitz neoplasms with benign histopathological features and, if such testing is performed, benign cytogenetic and molecular findings, are termed Spitz naevi. Spitz neoplasms with frankly malignant histopathological findings or ambiguous microscopic findings associated with genetic or genomic aberrations most in keeping with melanoma are designated as Spitz melanoma. Tumours with microscopic features and genetic/genomic aberrations in between naevi and melanomas are classified as Spitz melanocytoma. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 20-year-old woman who was diagnosed with Ewing sarcoma on her scalp. It mentions the benefits of using real-time polymerase chain reaction (RT-PCR) or fluorescence in situ hybridization (FISH) in the diagnosis of neoplasms such as ES breakpoint region 1 (EWSR1). It discusses the ES as a small cell tumor with neuroectodermal differentiation.

Background: Nevoid melanomas include melanomas with a low power silhouette similar to melanocytic nevi. However, at higher power magnification, nevoid melanoma may have severe nuclear atypia and dermal mitoses. Methods: We performed a clinical, pathological and molecular study on a series of 58 examples of nevoid melanoma, excluding cases with spitzoid morphology. Results: We identified distinct morphologic patterns: 'classic' nevoid melanoma, superficial spreading melanomas with nevoid invasive melanoma, lentigo maligna with nevoid invasive melanoma and deep penetrating nevus-like nevoid melanoma. Fluorescence in situ hybridization (FISH) was positive in 74% of cases. Copy number gains in 8q24 were common in amelanotic nevoid melanoma. The median follow-up was 28months (range 140). At last follow-up, 37 patients had no evidence of disease, 3 were alive with metastases and 6 died from metastatic melanoma. Of these six patients who died, four had a sentinel lymph node biopsy (SLNB) performed, which was negative in all four. Conclusions: We describe distinct clues to the diagnosis of nevoid melanoma including occult intraepidermal atypia, and expansile nesting resulting in asymmetric silhouette or dermal papillae expansion. We also describe that nevoid melanoma have infrequent SLNB involvement in aggressive cases, and have frequent 8q24 gains rather than 9p21 deletions. Our results suggest that nevoid melanoma are distinct from spitzoid melanomas and should be distinguished. [ABSTRACT FROM AUTHOR]

Variation in the melanocortin-1receptor (MC1R) gene is associated with pigmentary phenotypes and risk of malignant melanoma. Few studies have reported on MC1R variation with respect to tumor characteristics, especially clinically important prognostic features. We examined associations between MC1R variants and histopathological melanoma characteristics. Study participants were enrolled from nine geographic regions in Australia, Canada, Italy and the United States and were genotyped for MC1R variants classified as high-risk [R] (D84E, R142H, R151C, R160W, and D294H, all nonsense and insertion/deletion) or low-risk [r] (all other nonsynonymous) variants. Tissue was available for 2,160 white participants of the Genes, Environment and Melanoma (GEM) Study with a first incident primary melanoma diagnosis, and underwent centralized pathologic review. No statistically significant associations were observed between MC1R variants and AJCC established prognostic tumor characteristics: Breslow thickness, presence of mitoses or presence of ulceration. However, MC1R was significantly associated with anatomic site of melanoma (p = 0.002) and a positive association was observed between carriage of more than one [R] variant and melanomas arising on the arms (OR = 2.39; 95% CI: 1.40, 4.09). We also observed statistically significant differences between sun-sensitive and sun-resistant individuals with respect to associations between MC1R genotype and AJCC prognostic tumor characteristics. Our results suggest inherited variation in MC1R may play an influential role in anatomic site presentation of melanomas and may differ with respect to skin pigmentation phenotype. [ABSTRACT FROM AUTHOR]

Granular cell change in basal cell carcinoma ( BCC) occurs rarely. Only 11 such cases have been reported; all of them were solitary nodular BCC. We report herein a case of multiple granular cell BCC with infundibulocystic features. The tumors presented as papules on the anterior neck of a 44-year-old female with a prior history of a well-differentiated squamous cell carcinoma ( SCC) of the tongue and radiation involving the area in which BCC developed. Microscopically, the tumors were circumscribed small dermal nodules composed of epithelial cords with granular eosinophilic cytoplasm and entrapped infundibular keratocysts. Given the eosinophilic appearance of the tumor, history of SCC and the lesions multiplicity, the initial biopsy was first interpreted as metastatic SCC. The correct diagnosis of granular cell BCC was established upon rereview of the slides at a cancer center. Given the diagnostic controversy, immunohistochemical stains were performed. The tumor cells expressed Ber- EP4, CD63 ( NKI/ C3) and CD68. The tumors were compared to the prior SCC finding different morphologies. Extensive clinical evaluation showed no evidence of recurrent SCC. This report expands the clinicopathologic spectrum of granular cell variant of BCC and documents for the first time eruption of multiple such tumors in a localized area. [ABSTRACT FROM AUTHOR]

BACKGROUND: Merkel cell carcinoma (MCC) is a rare cutaneous neuroendocrine neoplasm whose natural history is poorly understood. Here, the authors describe their experience with a large cohort of patients who were treated at a single institution to describe patterns of recurrence after curative therapy. METHODS: Review of a prospective database was performed. Patient-related, tumor-related, and treatment-related variables were recorded, and the site and timing of initial recurrence were recorded. Factors associated with receipt of adjuvant therapy and recurrence were determined. RESULTS: In total, 364 patients with stage I through III MCC who underwent complete resection were identified. Adjuvant local radiation therapy (RT), lymph node RT, and chemotherapy were received selectively by 23%, 23%, and 15% of patients, respectively. Factors associated with the receipt of adjuvant therapy included younger age, primary tumor features (larger size, lymphovascular invasion [LVI], positive margin excision), and increasing pathologic stage. With median follow-up of 3.6 years, 108 patients (30%) developed a recurrence, including 11 local recurrences (3%), 12 in-transit recurrences (3%), 43 lymph node recurrences (12%), and 42 distant recurrences (12%). Clinically involved lymph nodes, primary tumor LVI, and a history of leukemia/lymphoma were predictive of recurrence. The majority of recurrences (80%) occurred in patients who had clinically involved lymph nodes or patients who did not undergo pathologic lymph node evaluation. CONCLUSIONS: A low recurrence rate in patients with clinically lymph node-negative MCC was achieved with adequate surgery (including sentinel lymph node biopsy) and the selective use of adjuvant RT for high-risk tumors. In contrast, patients with clinically lymph node-positive MCC had significantly higher rates of recurrence, especially distant recurrence. The authors concluded that contemporary natural history studies are critical in designing treatment pathways and clinical trials for MCC. Cancer 2011. © 2011 American Cancer Society. [ABSTRACT FROM AUTHOR]

Metastatic melanoma can on rare occasion simulate the appearance of a blue nevus clinically and/or histopathologically, which may lead to diagnostic confusion and delay in treatment. Given the known difficulty in recognizing a small dermal blue nevus-like melanoma metastasis by light microscopic findings alone, recent discoveries of unique cytogenetic aberrations in various types of melanomas have led pathologists to explore cytogenetic techniques as an ancillary diagnostic tool. Herein, we report a case of a 58-year-old man with a history of uveal melanoma, in which fluorescence in situ hybridization (FISH) analysis for monosomy 3 helped confirm a diagnosis of blue nevus-like uveal melanoma metastasis. The patient had presented clinically with a new small 1-mm dark blue-gray macule on the forehead. Histopathologically, a small dermal nodule of pigmented epithelioid melanocytes and melanophages was found with a rare mitotic figure. The pathologist's suspicion of a blue nevus-like melanoma metastasis was confirmed by FISH analysis: both the tumor cells of the patient's prior uveal melanoma and the melanocytes of the new dermal blue nevus-like nodule carried only one copy of chromosome 3. Furthermore, deletion of 1p36 and amplifications of 8q32 were also identified. Busam KJ, Fang Y, Jhanwar S, Lacouture M. Diagnosis of blue nevus-like metastatic uveal melanoma confirmed by fluorescence in situ hybridization (FISH) for monosomy 3. [ABSTRACT FROM AUTHOR]

The authors have indicated no significant interest with commercial supporters. [ABSTRACT FROM AUTHOR]

The authors have indicated no significant interest with commercial supporters. [ABSTRACT FROM AUTHOR]

A conjunctival melanocytic nevus may on occasion be difficult to distinguish from melanoma both clinically and histopathologically. An unambiguous correct diagnosis is critical because of major differences in management and prognosis. We evaluated a fluorescence in situ hybridization (FISH) assay, which has previously been shown to be of value for the diagnosis of melanocytic nevi and melanomas of the skin, using probes targeting 6p25 (RREB1), 6q23 (MYB), 11q13 (CCND1) and centromere 6 (CEP6), for its potential to assist in the distinction of conjunctival melanocytic nevi from melanomas. Four melanocytic nevi and eight melanomas of the conjunctiva were analyzed. Two of the melanomas were diagnostically problematic because of suboptimal histopathology. None of the conjunctival melanocytic nevi showed a level of chromosomal aberrations that met FISH criteria for a diagnosis of melanoma. All eight conjunctival melanomas (six unequivocal and two suspicious lesions) met FISH criteria for melanoma. Thus, results from FISH assay targeting 6p25, 6q23, 11q13 and centromere 6 correlated well with the histopathologic diagnoses and supported the histopathologic suspicion in two problem cases. The findings encourage further exploration of this technique as an ancillary method for the work-up of conjunctival melanocytic proliferations. Busam KJ, Fang Y, Jhanwar SC, Pulitzer MP, Marr B, Abramson DH. Distinction of conjunctival melanocytic nevi from melanomas by fluorescence in situ hybridization. [ABSTRACT FROM AUTHOR]

Abstract: Background: Patients with subungual melanoma (SM) often experience delayed diagnosis and present with deep primary lesions. Breslow depth of the primary lesion is often unknown before definitive resection, thus complicating treatment planning. Methods: Patients with SM treated at our institution from 1992 to 2004 were identified from our prospective melanoma database. Clinical and pathologic factors were reviewed; Student t test and Kaplan-Meier method were used for statistical analysis. Results: Forty-nine patients were identified; most were female (63%). The median age was 66 years (range 24 to 83). The most common site was the great toe (n = 21), followed by the thumb (n = 15). Eight patients had in situ disease; 6 were treated initially with wide local excision, and 4 of these eventually required amputation. The median Breslow depth of invasive lesions was 2.1 mm (range .2 to 11). Toe lesions were thicker than finger lesions (mean 3.5 vs 2.5 mm, P = .005). Patients with invasive SM of the toe had a less favorable outcome than those with finger lesions (5-year overall survival 40% vs 72%, respectively; P = .05). Sentinel lymph node (SLN) biopsy was performed in 30 patients and was positive in 5 (17%); all underwent completion lymphadenectomy. Median Breslow depth in patients with positive SLN was 4 mm (range 1.2 to 11). Four of 5 patients with positive SLN developed recurrence (median 16 months); 3 patients died of disease within 40 months. Conclusions: Patients with SM present distinct therapeutic challenges. They continue to present with deep primary melanoma, particularly on the toe. Undertreatment of early disease is associated with local recurrence. [Copyright &y& Elsevier]

Clusterin is a pleiotrophic glycoprotein that has been implicated in diverse physiologic processes. Recent studies of gene expression profiling found clusterin to be expressed in desmoplastic variants of malignant melanoma. In this study, we extended those observations and examined clusterin expression in a larger number of primary as well as in metastatic melanomas and melanocytic nevi. We used tissue microarray panels as well as selected conventional sections from formalin-fixed and paraffin-embedded tissue blocks. Positive staining for clusterin was found in seven of 21 (30°o) primary desmoplastic and three of 21 (7°o) non-desmoplastic melanoma. Among metastatic tumors, clusterin expression was found in five of 37 tumors (13.5°o). Clusterin expression was not seen in melanocytes of normal skin or in any of the 10 melanocytic nevi tested. Clusterin expression was not entirely restricted to melanoma; it was also seen in a few non-neoplastic tissues, including perifollicular fibroblasts, occasional sebocytes, and the epithelial cells lining sebaceous duct and the isthmus of the hair follicle. Our findings confirm the observation that clusterin can be expressed in melanoma, in particular primary desmoplastic melanoma. However, clusterin appears to be present only in a minority of melanomas. [ABSTRACT FROM AUTHOR]

BACKGROUND. Telepathology is an expanding technology in multiple fields for remote pathology diagnosis and consultation. The use of telepathology in Mohs surgery has been very limited. OBJECTIVE. To describe the clinical experience of using a telepathology system for intraoperative consultations on difficult frozen sections during Mohs surgery. MATERIALS AND METHODS. Intraoperative consultation with a dermatopathologist was obtained using a dynamic telepathology system for all questions arising on frozen sections during Mohs surgery for nonmelanoma skin cancers during a 2-year period. RESULTS. The most common reason for consultation was to distinguish basal cell carcinoma from a benign histologic simulant on Mohs frozen sections. Other uses included determining tumor histology and distinguishing inflammation from residual tumor. CONCLUSION. Dynamic telepathology is a useful and convenient adjunct in the Mohs surgery practice for intraoperative consultations on difficult frozen sections. [ABSTRACT FROM AUTHOR]

Desmoplastic melanoma (DM) is a variant of melanoma characterized by the presence of amelanotic fusiform melanocytes dispersed in a prominent collagenous stroma. DM behaves differently from conventional non-desmoplastic melanoma (NDM). It has a higher tendency for local recurrence and is less likely to metastasize to regional lymph nodes. In this study, we explored the possibility of distinguishing DM from NDM by gene expression profiling. RNA samples from ten primary cutaneous melanomas of similar depth of invasion were analyzed using the Affymetrix U133A oligonucleotide platform. Four tumors were DM, five were ND, and one tumor showed combined features of desmoplastic and conventional. Hierarchical cluster analysis clearly separated DM from NDM. The expression of a number of melanocyte differentiation genes was decreased in DM compared with NDM, which corresponded to immunohistochemical results. Various genes were upregulated in DM, including neurotrophic factors and genes involved in extracellular matrix production. A novel finding was the high expression of clusterin in DM, which was confirmed by immunohistochemical studies. Our results from gene expression profiling validate the distinction of DM from NDM. They also provide the opportunity to learn more about the biology of DM which had previously not yet been associated with this variant of melanoma. [ABSTRACT FROM AUTHOR]

Unusual or atypical melanocytic nevi can be confused with malignant melanoma. Two patients are presented here with a rare variant of melanocytic nevus. Both were men. One was 39 years old and sought medical attention after trauma of a ‘congenital mole’. The other was 24 years old and presented with a history of a slowly growing lesion, which had been known since childhood. In both patients, the lesion occurred on the buttock. They were dermal and superficial subcutaneous nodules measuring 1.5 and 2.3 cm in greatest dimension, respectively. The tumors were composed of densely cellular fascicles of melanocytes arranged in a lobulated growth pattern. Rare nests of small epithelioid melanocytes were also seen. No melanin pigment was seen on hematoxylin and eosin-stained sections. Focal minimal pigment was noted by Fontana–Masson stain in one case. Involvement of numerous peripheral nerve trunks by fusiform melanocytes was a prominent feature. Rare mitotic figures were seen in melanocytes [1–2 mitoses per 50 high-power fields (HPF)]. The MIB-1 labeling index was low (less than 5% of the lesional cell population was immunopositive). Both tumors were excised with negative surgical margins. One patient underwent sentinel lymph node biopsy because there was controversy regarding the biologic potential of the lesion. No melanocytic tumor deposits were found in the lymph nodes. On clinical follow up of 11 years and 18 months after complete excision, both patients are alive and well with no evidence of recurrence. We regard these lesions as congenital monophasic and pauci-melanotic variants of cellular blue nevus. The nevi are presented here to enhance our knowledge of the morphologic spectrum of melanocytic tumors and to help avoid confusion with malignant melanoma. Busam KJ, Lohmann CM. Congenital pauci-melanotic cellular blue nevus. [ABSTRACT FROM AUTHOR]

Diffuse melanosis is a rare event associated with advanced metastatic malignant melanoma. A 35-year-old woman with stage IV melanoma is presented, who developed slate bluish-gray to brown discoloration of her skin after chemotherapy-induced tumor lysis syndrome. A number of studies were performed to re-evaluate possible mechanisms of melanosis. Skin tissue was examined on routine hematoxylin-and-eosin-stained sections, Fontana stains, immunohistochemical studies with antibodies for Melan-A, gp100, tyrosinase, FXIIIa, and CD68, and by electron microscopy. The main cell types found to contain melanin pigment were histiocytes and dendritic cells. In the dermis, they were distributed mainly around venules. In the subcutaneous fat, they were scattered throughout the fat lobule. Melanin pigment was not only seen within cells but also extracellularly. No melanoma cells were seen in the skin. No increase in melanin pigment or number of melanocytes was seen in the epidermis. A bone marrow biopsy contained melanophages but no melanoma cells. Ultrastructural examination of the patient's serum revealed the presence of melanosomes. Sequence analysis of the tumor's cDNA failed to identify any mutations in the tyrosinase gene, and no tyrosinase protein was detected in non-melanocytic cells, indicating that it was unlikely that a mutation had resulted in a secretory form of the protein. These findings document that diffuse melanosis may result from tumor lysis, with release of melanosomes into the bloodstream. Busam KJ, Wolchek J, Jungbluth AA, Chapman P. Diffuse melanosis after chemotherapy-induced tumor lysis syndrome in a patient with metastatic melanoma. [ABSTRACT FROM AUTHOR]

Background: Malignancies may be associated with paraneoplastic cutaneous manifestations, including pigmentary disorders. Methods: The clinical findings were reviewed. Skin and tumor tissue samples were examined by routine histology, immunohistochemistry, and in one case also by electron microscopy. Results: Two patients developed diffuse melanotic macules and papules associated with visceral adenocarcinoma. One patient was a 64-year-old man with advanced carcinoma of the distal esophagus. The other was a 62-year-old man with metastatic pulmonary adenocarcinoma. The detection of the primary tumor in both patients was preceded by the rapid onset of melanotic macules and papules in the anogenital region and in one patient also around both nipples. The pigmented lesions were histologically characterized by a lentiginous melanocytic proliferation of large and heavily pigmented melanocytes associated with hyperpigmentation of adjacent keratinocytes. Both patients had been misdiagnosed as having epidermotropic metastatic malignant melanoma. None of them had prior, concurrent, or subsequent cutaneous or extracutaneous invasive melanoma. Both patients died of metastatic adenocarcinoma. Conclusion: Eruptive melanotic macules and papules represent an under-recognized paraneoplastic syndrome. The cases illustrate a diagnostic pitfall for clinicians and pathologists unaware of this phenomenon. [ABSTRACT FROM AUTHOR]

Objective.--Primary mucosal melanomas are rare tumors. We compare melanomas arising in 2 histologically different mucosa, the stratified oral squamous mucosa and pseudostratified sinonasal respiratory mucosa, to investigate the clinicopathologic influence of native mucosal histology on the tumor. Methods.--Clinicopathologic features of 36 melanomas arising in the squamous mucosa of the oral cavity were compared with 59 melanomas arising in the sinonasal respiratory mucosa. Results--The median age of patients was 61 and 63 years for oral and sinonasal melanomas, respectively, with the squamous and respiratory mucosa covering the maxilla being most frequently involved (68.7% and 66%, respectively). The former had a remarkable male predilection (28 men, 8 women), while the latter affected both sexes equally (29 men, 30 women). The oral melanomas were more likely to be detected in the early in situ or microinvasive stage (4 cases vs none, P = .008) and were more frequently amelanotic (14 vs 12, P = .049) than sinonasal melanomas. The sinonasal melanomas were frequently thicker (median thickness, 9 vs 2.6 mm), polypoid (29 vs none), ulcerated (57 vs 20), and necrotic (57 vs 14) than oral melanoma ( P < .001). Pseudopapillary architecture was more frequent in sinonasal melanomas (16 tumors vs none, P < .001), and desmoplastic melanomas were more frequent in the oral mucosa (6 vs 1, P = .005). Sinonasal melanoma showed vascular and deep tissue invasion more frequently than oral melanoma; however, no significant difference in disease-specific survival was noted (median survival, 2.8 years vs 3.0 years; 5-year survival, 37% vs 35%, respectively). Conclusion.--Sinonasal melanomas demonstrated aggressive morphologic features significantly more frequently than oral melanomas; however, prognosis remained similar in both groups. [ABSTRACT FROM AUTHOR]

BACKGROUND. Basal cell carcinoma shows a wide spectrum of clinical and histologic appearances. A distinct tumor variant with follicular infundibulocystic differentiation is recognized, and there are only a few reports on its clinical presentation and management. OBJECTIVE. To report a case of multiple infundibulocystic basal cell carcinomas with a unique unilateral presentation. METHODS. A clinical history was obtained. Photographs were taken, and punch biopsies were performed. RESULTS. An 83-year-old Caucasian female presented with multiple unilateral, asymptomatic, skin-colored, dome-shaped papules around the right mouth for 11 years without apparent change. Punch biopsies revealed findings typical of infundibulocystic basal cell carcinoma. CONCLUSIONS. A patient with clinically indolent multiple unilateral infundibulocystic basal cell carcinomas is described. Given the location of these multiple lesions, standard treatment modalities for basal cell carcinomas would have significant cosmetic and functional implications. A management approach with clinical follow-up and surgical intervention only for changing lesions is discussed. [ABSTRACT FROM AUTHOR]

background. Use of intralesional corticosteroids in the management of keratoacanthomas has been reported in older literature. Yet this therapy is no longer a commonly considered treatment option. objective. To report management of a therapeutically challenging patient with multiple eruptive keratoacanthomas with intralesional corticosteriod treatment to revive awareness of this treatment option. methods. A 55-year-old female with frequent episodes of multiple eruptive keratoacanthomas was treated with intralesional corticosteroids and methotrexate. results. Intralesional corticosteroids successfully treated eruptive keratoacanthomas with complete regression and minimal scarring within 2-4 weeks. conclusion. Despite its limitations, intralesional corticosteroids may have a role in the treatment of select keratoacanthomas. [ABSTRACT FROM AUTHOR]

background. Telepathology is an emerging technology for remote pathology consultation and diagnosis. objective. To assess the diagnostic accuracy and utility of a dynamic telepathology system in the setting of Mohs surgery. methods. Using a dynamic telepathology system, a single dermatopathologist at a remote site assessed the following cases: (1) 50 fixed-tissue slides of basal and squamous cell carcinomas for pathologic diagnosis; (2) 40 frozen-section slides from Mohs surgery for the presence or absence of tumor; (3) 20 frozen-section slides from Mohs surgery for intraoperative consultation with the Mohs surgeon. All 110 slides were then randomly reviewed by the same dermatopathologist by conventional light microscopy. Telepathology and conventional light microscopy diagnoses were then compared. results. There was complete agreement between telepathology and conventional light microscopy diagnoses. conclusion. Dynamic telepathology is a convenient, useful, and accurate system for remote diagnosis and consultation in the setting of Mohs surgery. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Methods Results Conclusions Mpox (formerly known as monkeypox), a zoonotic disease caused by Monkeypox virus (MPXV), has become an international outbreak since May 2022. Mpox often presents with a mild systemic illness and a characteristic vesiculopustular skin eruption. In addition to molecular testing, histopathology of cutaneous lesions usually shows distinctive findings, such as epidermal necrosis, balloon degeneration, papillary dermal edema, and focal dermal necrosis, which have proven helpful in the diagnosis of mpox. Viral cytopathic changes with areas of multinucleation, smudging of the nuclei, and intracytoplasmic inclusions have also been described. Although useful, these features are relatively nonspecific. The use of a monoclonal antibody for immunohistochemical (IHC) staining of MPXV may be a useful tool in confirming mpox infection.Three cases of PCR‐confirmed mpox were biopsied and subjected to IHC staining with a monoclonal MPXV‐specific antibody targeting viral envelope protein A29. As controls, cell lines transduced to express other MPXV viral antigens and samples of cutaneous viral infections involving Molluscum contagiosum, Herpes simplex, Herpes zoster, or Cytomegalovirus were also subjected to IHC staining with this antibody.All three mpox patient biopsies performed on lesional skin subjected to MPXV IHC staining reliably detected viral infection in lesional skin with a diffuse cytoplasmic and focally nuclear staining pattern. No staining was seen in transduced cell lines expressing off‐target MPXV viral antigens and in lesional skin of other common viral infections listed above.The monoclonal MPXV‐specific antibody may be used as an adjunct tool to confirm mpox infection. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 12-year-old boy suffering from desmoplastic trichoepithelioma (DTE). Initially, a shave biopsy resulted in the diagnosis of right cheek squamous cell carcinoma (SCC), keratoacanthoma (KA) type. Thereafter, histopathologic examination showed a papillomatous and keratocystic squamous proliferation.

A letter to the editor is presented which is concerned with two cases of keratoacanthoma that were associated with imatinib mesylate

We simply report the findings to alert practicing dermatopathologists to the risk for false-positive test results with this GEP test, and that it may be enriched for Spitz tumors (Figure 1). Melanocytic neoplasms can be diagnostically challenging using light microscopy alone.[1] Because the histopathologic findings can be ambiguous, various ancillary methods have been explored to assist in the diagnosis. Malignant melanoma test results by a commercial 35-gene expression test are enriched for benign or atypical Spitz tumors. [Extracted from the article]

Summary: Histiocytic neoplasms are diverse clonal haematopoietic disorders, and clinical disease is mediated by tumorous infiltration as well as uncontrolled systemic inflammation. Individual subtypes include Langerhans cell histiocytosis (LCH), Rosai–Dorfman–Destombes disease (RDD) and Erdheim–Chester disease (ECD), and these have been characterized with respect to clinical phenotypes, driver mutations and treatment paradigms. Less is known about patients with mixed histiocytic neoplasms (MXH), that is two or more coexisting disorders. This international collaboration examined patients with biopsy‐proven MXH with respect to component disease subtypes, oncogenic driver mutations and responses to conventional (chemotherapeutic or immunosuppressive) versus targeted (BRAF or MEK inhibitor) therapies. Twenty‐seven patients were studied with ECD/LCH (19/27), ECD/RDD (6/27), RDD/LCH (1/27) and ECD/RDD/LCH (1/27). Mutations previously undescribed in MXH were identified, including KRAS, MAP2K2, MAPK3, non‐V600‐BRAF, RAF1 and a BICD2‐BRAF fusion. A repeated‐measure generalized estimating equation demonstrated that targeted treatment was statistically significantly (1) more likely to result in a complete response (CR), partial response (PR) or stable disease (SD) (odds ratio [OR]: 17.34, 95% CI: 2.19–137.00, p = 0.007), and (2) less likely to result in progression (OR: 0.08, 95% CI: 0.03–0.23, p < 0.0001). Histiocytic neoplasms represent an entity with underappreciated clinical and molecular diversity, poor responsiveness to conventional therapy and exquisite sensitivity to targeted therapy. [ABSTRACT FROM AUTHOR]

"Cutaneous melanocytic tumor with CRTC1‐TRIM11 fusion" (CMTCT) is a newly described, potentially novel entity that typically presents as a dermal nodule on the head and neck, extremities, and trunk of adults. Histopathologically, it is reported as a nodular or multinodular tumor composed of epithelioid and spindle cells that are variably immunoreactive for S100‐protein, SOX10, and MITF along with more specific melanocytic markers such as MelanA and HMB45. With only 11 cases reported in the English literature so far, the neoplasm appears to behave in a relatively indolent fashion. Nevertheless, in one case, local recurrence and synchronous distant metastasis were evident after 13 years. Additional cases with longer follow‐up are essential to determine the neoplasm's biologic behavior with more accuracy. Herein, two cases of CMTCT, one arising on the lower back of a 65‐year‐old female and the other on the arm of a 33‐year‐old female in addition to a comprehensive literature review are reported. [ABSTRACT FROM AUTHOR]

The article describes a case study of cutaneous and systemic plasmacytosis in a healthy Japanese man in his late 1960s with no relevant personal or family history. The patient presented with a worsening pruritic skin eruption of ten years' in duration. Other topics discussed include findings of physical, laboratory and histopathologic examinations, patient management, and a description of cutaneous plasmacytosis.

A letter to the editor is presented which describes an investigation into inter-observer concordance for angiotropism in human melanoma.

Presents an introduction to the September 1, 2005 issue of the "Journal of Investigative Dermatology."

Simple Summary: Merkel cell carcinoma (MCC) and small cell lung cancer (SCLC) are both neuroendocrine cancers that can resemble each other under the microscope. Immunostaining with diagnostic markers such as cytokeratin 20 (CK20) and thyroid transcription factor 1 (TTF-1) can help differentiate these two cancers, but their sensitivity and specificity are limited. We compared the gene expression of MCC and SCLC tumors to identify highly differentially expressed genes for potential use as diagnostic markers. Two candidate markers for MCC, atonal BHLH transcription factor 1 (ATOH1) and transcription factor AP-2β (TFAP2B), and one candidate marker for SCLC, carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6), were tested using immunostaining. Combined use of CEACAM6 with TTF-1 increased SCLC diagnostic sensitivity to 93% and specificity to 98%. A panel of CK20, ATOH1, and TFAP2B was 100% sensitive and specific for MCC, suggesting the potential utility of these new markers in differentiating MCC and SCLC. Merkel cell carcinoma (MCC) and small cell lung cancer (SCLC) can be histologically similar. Immunohistochemistry (IHC) for cytokeratin 20 (CK20) and thyroid transcription factor 1 (TTF-1) are commonly used to differentiate MCC from SCLC; however, these markers have limited sensitivity and specificity. To identify new diagnostic markers, we performed differential gene expression analysis on transcriptome data from MCC and SCLC tumors. Candidate markers included atonal BHLH transcription factor 1 (ATOH1) and transcription factor AP-2β (TFAP2B) for MCC, as well as carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6) for SCLC. Immunostaining for CK20, TTF-1, and new candidate markers was performed on 43 MCC and 59 SCLC samples. All three MCC markers were sensitive and specific, with CK20 and ATOH1 staining 43/43 (100%) MCC and 0/59 (0%) SCLC cases and TFAP2B staining 40/43 (93%) MCC and 0/59 (0%) SCLC cases. TTF-1 stained 47/59 (80%) SCLC and 1/43 (2%) MCC cases. CEACAM6 stained 49/59 (83%) SCLC and 0/43 (0%) MCC cases. Combining CEACAM6 and TTF-1 increased SCLC detection sensitivity to 93% and specificity to 98%. These data suggest that ATOH1, TFAP2B, and CEACAM6 should be explored as markers to differentiate MCC and SCLC. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 52-year-old male patient of Turkish descent with a history of mantle cell lymphoma who was treated with the help of chemotherapy, autologous stem-cell transplantation, and rituximab. Topics discussed include the association between Kaposi's sarcoma and human herpesvirus 8, four principal clinical variants of Kaposi's sarcoma such as classic, endemic, and iatrogenic, and immunosuppressive drugs such as corticosteroids and cyclosporine for Kaposi's sarcoma.

GLO:FQL/01feb20:ajd13152-fig-0002.jpg PHOTO (COLOR): (a) The histopathology slide of the original right lateral canthus biopsy contained three pieces of tissue (H&E); however, the biopsy-report gross description stated: 'two-minute skin punches biopsies each measuring 0.1 × 0.1 cm in diameter'. Patient and tissue misidentification are mostly secondary to human error and can occur at any step.[[1]] Tissue mismatch involving prostate or breast needle core biopsies have been documented[[1], [3]] even in most regulated settings such as clinical trials. [Extracted from the article]

BACKGROUND Cutaneous squamous cell carcinoma (cSCC) of the ear is associated with poor outcomes. No studies have evaluated current staging system performance in this specific location. OBJECTIVE Describe clinicopathologic characteristics and outcomes of ear cSCC and evaluate the performance of current staging systems. METHODSRetrospective study including cases diagnosed and treated at a cancer center from January 2000 to December 2014. Demographic, clinical, and pathologic data were collected from clinical records. Biopsy slides were rereviewed and patients were staged according to the American Joint Committee on Cancer (AJCC) seventh, eighth, and Brigham Women's Hospital (BWH) staging. RESULTS Of 125 patients, the mean age at diagnosis was 71.9 years (SD 12.5), with most men (89.6%, n5112). Median follow-up was 22.3 months. Local recurrence and survival risk factors were similar to cSCC outside the ear. The Akaike's Information Criterion (AIC) estimates showed that the BWH system better predicted outcomes than the AJCC seventh, and the AJCC eighth, with AIC values of 189.9, 270.5, and 274.1, respectively. Limitations of the study include retrospective design, single center study, and no control group. CONCLUSION Current staging systems perform well at stratifying risk in ear cSCC. [ABSTRACT FROM AUTHOR]

Primary cutaneous neuroendocrine carcinoma, also known as Merkel cell carcinoma (MCC), usually presents as a dermal and/or subcutaneous tumor. Rarely, it is confined to the epidermis or adnexal epithelium [MCC in situ (MCCIS)]. Little is known about the spectrum of features and biology of MCCIS. Herein, we report a case of MCCIS arising on the cheek of a 77-year-old Caucasian male, which was associated with squamous cell carcinoma in situ. The tumor cells of both the neuroendocrine and squamous components prominently involved adnexal structures but did not invade the dermis. The tumor cells with neuroendocrine features were immunoreactive for cytokeratin-20, chromogranin and synaptophysin. They also expressed p53 but were non-reactive with the monoclonal antibody CM2B4. Lack of labeling for CM2B4 is in keeping with prior observations of combined squamous and MCC. Our findings support the concept of a distinct subtype of virus-independent cutaneous neuroendocrine carcinoma that differs from conventional MCC. The observed overexpression of p53 suggests that the development of this tumor type may be related to chronic ultraviolet damage. Tan BH, Busam KJ, Pulitzer MP. Combined intraepidermal neuroendocrine (Merkel cell) and squamous cell carcinoma in situ with CM2B4 negativity and p53 overexpression. [ABSTRACT FROM AUTHOR]

Simple Summary: Melanoma is the most severe type of skin cancer, and the risk of developing melanoma and of dying of melanoma varies between women and men. This study investigated whether widely studied genetic single nucleotide polymorphisms (SNPs) in two oncogenes known to promote cell proliferation explain these sex differences by testing such variants in a large cohort of 3663 melanoma patients. Formal analyses demonstrated that females, but not males, who carried the variant MDM4-rs4245739*C were more likely to develop a new primary melanoma, and those with the variant MDM2-rs2279744*G were less likely to succumb to the disease. We also identified a number of additional variants, often co-inherited with the tested SNPs, which modify how these and other genes work locally in the skin, as well as in distal organs where melanoma tends to spread or invade during the progression of the disease. MDM2-SNP309 (rs2279744), a common genetic modifier of cancer incidence in Li-Fraumeni syndrome, modifies risk, age of onset, or prognosis in a variety of cancers. Melanoma incidence and outcomes vary by sex, and although SNP309 exerts an effect on the estrogen receptor, no consensus exists on its effect on melanoma. MDM2 and MDM4 restrain p53-mediated tumor suppression, independently or together. We investigated SNP309, an a priori MDM4-rs4245739, and two coinherited variants, in a population-based cohort of 3663 primary incident melanomas. Per-allele and per-haplotype (MDM2_SNP309-SNP285; MDM4_rs4245739-rs1563828) odds ratios (OR) for multiple-melanoma were estimated with logistic regression models. Hazard ratios (HR) for melanoma death were estimated with Cox proportional hazards models. In analyses adjusted for covariates, females carrying MDM4-rs4245739*C were more likely to develop multiple melanomas (ORper-allele = 1.25, 95% CI 1.03–1.51, and Ptrend = 0.03), while MDM2-rs2279744*G was inversely associated with melanoma-death (HRper-allele = 0.63, 95% CI 0.42–0.95, and Ptrend = 0.03). We identified 16 coinherited expression quantitative loci that control the expression of MDM2, MDM4, and other genes in the skin, brain, and lungs. Our results suggest that MDM4/MDM2 variants are associated with the development of subsequent primaries and with the death of melanoma in a sex-dependent manner. Further investigations of the complex MDM2/MDM4 motif, and its contribution to the tumor microenvironment and observed associations, are warranted. [ABSTRACT FROM AUTHOR]

Background: Cutaneous metastases in pancreatic cancer (PC) are rare. Herein, we evaluate the clinical, genomic, and other descriptors of patients with PC and cutaneous metastases. Methods: Institutional databases were queried, and clinical history, demographics, PC cutaneous metastasis details, and overall survival (OS) from cutaneous metastasis diagnosis were abstracted. OS was estimated using Kaplan–Meier methods. Results: Forty patients were identified, and median age (Q1–Q3, IQR) of PC diagnosis was 66.0 (59.3–72.3, 12.9) years. Most patients had Stage IV disease at diagnosis (n = 26, 65%). The most common location of the primary tumor was the tail of the pancreas (n = 17, 43%). The most common cutaneous metastasis site was the abdomen (n = 31, 78%), with umbilical lesions occurring in 74% (n = 23) of abdominal lesions. The median OS (95% CI) was 11.4 months (7.0, 20.4). Twenty‐three patients had umbilical metastases (58%), and 17 patients had non‐umbilical metastases (43%). The median OS (95% CI) was 13.7 (7.0, 28.7) months in patients with umbilical metastases and 8.9 (4.1, Not reached) months in patients with non‐umbilical metastases (p = 0.1). Sixteen of 40 (40%) patients underwent somatic testing, and findings were consistent with known profiles. Germline testing in 12 (30%) patients identified pathogenic variants in patients: CHEK2, BRCA1, and ATM. Conclusion: Cutaneous metastases from PC most frequently arise from a pancreas tail primary site and most frequently occur in the umbilicus. Cutaneous metastases may generally be categorized as umbilical or non‐umbilical metastases. [ABSTRACT FROM AUTHOR]

Background Multiple BAP1 negative melanocytic neoplasms are a hallmark of familial cancer susceptibility syndrome caused by BAP1 germline mutation. The syndrome is characterized by increased incidence of renal cell carcinoma, mesothelioma, cholangiocarcinoma, cutaneous and uveal melanoma and some other neoplasms. Methods We report histomorphologic characteristics of six cutaneous melanocytic neoplasms with loss of BAP1 expression in two members of a family with BAP1-associated cancer susceptibility syndrome. Results The neoplasms were dermal melanocytic nevi characterized by a proliferation of large epithelioid (spitzoid) melanocytes, and adipocytic metaplasia. Nuclear pseudoinclusions and multinucleated melanocytes were present in most neoplasms. In two of the cases, a nodular melanoma was found associated with a dermal nevus. None of the melanomas recurred or metastasized after 6 and 3 years of follow up. Conclusions We report two new cases of melanoma arising in a BAP1-deficient melanocytic nevus in the setting of familial tumor predisposition syndrome. Adipocytic metaplasia and nuclear pseudoinclusions may be additional morphologic clues to a BAP1-deficient nevus. It remains to be seen whether these features are more common in familial than sporadic lesions. [ABSTRACT FROM AUTHOR]

It is unclear why some melanomas aggressively metastasize while others remain indolent. Available studies employing multi‐omic profiling of melanomas are based on large primary or metastatic tumors. We examine the genomic landscape of early‐stage melanomas diagnosed prior to the modern era of immunological treatments. Untreated cases with Stage II/III cutaneous melanoma were identified from institutions throughout the United States, Australia and Spain. FFPE tumor sections were profiled for mutation, methylation and microRNAs. Preliminary results from mutation profiling and clinical pathologic correlates show the distribution of four driver mutation sub‐types: 31% BRAF; 18% NRAS; 21% NF1; 26% Triple Wild Type. BRAF mutant tumors had younger age at diagnosis, more associated nevi, more tumor infiltrating lymphocytes, and fewer thick tumors although at generally more advanced stage. NF1 mutant tumors were frequent on the head/neck in older patients with severe solar elastosis, thicker tumors but in earlier stages. Triple Wild Type tumors were predominantly male, frequently on the leg, with more perineural invasion. Mutations in TERT, TP53, CDKN2A and ARID2 were observed often, with TP53 mutations occurring particularly frequently in the NF1 sub‐type. The InterMEL study will provide the most extensive multi‐omic profiling of early‐stage melanoma to date. Initial results demonstrate a nuanced understanding of the mutational and clinicopathological landscape of these early‐stage tumors. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 67-year-old man with a nodular and infiltrative basal cell carcinoma (BCC) of the right medial eyebrow. The patient, whose medical history included atrial fibrillation, underwent five stages of Mohs micrographic surgery (MMS). The authors find the case challenging due to rare findings of a classic BCC within an unusual benign trichoblastic and spiradenomatous proliferation background. The differences between BCC and trichoblastoma are also discussed.

Pediatric melanoma is a rare disease about which there is little agreement as to the accurate diagnosis of borderline lesions or early lymph node metastases. A better understanding of the natural history of this condition will require large centralized registries, consistent histopathologic and cytogenetic review, and long term clinical follow‐up. [ABSTRACT FROM AUTHOR]

Clear cell sarcoma ( CCS) typically presents as a tumor in the deep soft tissue of extremities, but when centered in the dermis it may be confused with a melanocytic nevus, primary nodular or metastatic melanoma. Compound variants of CCS, i.e. tumor cells present in both the epidermis and underlying soft tissue have not yet been described. Herein we report such a case, which initially presented as a nodule on the left wrist of a young woman at 19 years of age. The lesion was then interpreted as 'Spitz nevus, compound type'. Twelve years later the patient noticed an enlarged lymph node in the right axilla. The excised lymph node was nearly completely replaced by malignant tumor cells, which were immunoreactive for S100 protein. They resembled the tumor cells of the wrist lesion. Cytogenetic analysis of the metastatic tumor revealed a t(12;22) translocation. Fluorescence in situ hybridization confirmed Ewing's sarcoma breakpoint region 1 ( EWSR1) rearrangement in 70% of the tumor cells, thereby supporting the diagnosis of metastatic CCS. Our case is of interest because it documents that CCS can involve the epidermis. This observation expands the morphological spectrum associated with this tumor. [ABSTRACT FROM AUTHOR]

Desmoplastic melanoma can be difficult to distinguish from desmoplastic melanocytic nevi both clinically and histopathologically. Several attempts have been made to explore the use of ancillary studies to facilitate this distinction. Prior work has suggested that immunohistochemical expression of p16 could help distinguish sclerosing Spitz nevi from desmoplastic melanomas. We re-evaluated the expression of p16 in 22 desmoplastic melanomas (13 mixed and 9 pure desmoplastic tumors) and five desmoplastic melanocytic nevi (three desmoplastic Spitz nevi and two congenital melanocytic nevi with prominent dermal sclerosis). All desmoplastic melanocytic nevi were strongly immunoreactive for p16. Of the 22 desmoplastic melanomas, 6 tumors failed to label for p16, 10 were focally positive, but 6 tumors were diffusely immunoreactive. The latter finding is relevant, as it points to limitations in the diagnostic value of immunohistochemical staining for p16 for the diagnosis of desmoplastic melanocytic proliferations. Diffuse staining for p16 is not restricted to desmoplastic Spitz nevi but can also occur in a subset of desmoplastic melanomas, and this warrants caution in the use of this marker for diagnostic purposes. [ABSTRACT FROM AUTHOR]

Objectives Nilotinib and dasatinib are second-generation tyrosine kinase inhibitors approved for the treatment of chronic myeloid leukemia ( CML). In clinical trials, they have both been reported to cause rash in a significant number of patients, but its incidence varies significantly and has not been characterized clinically or histologically. The aim of this study was to determine the incidence of rash with nilotinib and dasatinib, and to provide a clinical and histopathological description of the rash. Methods We conducted a meta-analysis of clinical trials evaluating nilotinib and dasatinib to determine and compare the incidence of rash with these medications. Additionally, we performed a retrospective chart review to analyze the clinical presentation and histology of patients presenting with rash. Results The incidence of all-grade (grade 1-4) rash with nilotinib was 34.3% (95% CI, 27.9-41.3), higher ( P = 0.017) than with dasatinib (23.3%; 95% CI, 18.8-28.6). Similarly, the incidence of high-grade rash with nilotinib (2.6%; 95% CI, 2.1-3.4) was higher ( P = 0.002) than with dasatinib (1.1%; 95% CI, 0.8-1.6). The clinical presentation often consisted of a pruritic, perifollicular hyperkeratotic, occasionally erythematous papular rash affecting most areas of the body, depending on the severity. Conclusions Both nilotinib and dasatinib are associated with rash in a significant number of patients. Further studies to prevent and treat rash with nilotinib and dasatinib are required to improve patient quality of life, adherence with therapy and oncologic outcome. [ABSTRACT FROM AUTHOR]

Desmoplastic melanocytic nevi can be difficult to distinguish from desmoplastic melanoma. The presence of lymphocytic aggregates in association with a sclerosing melanocytic proliferation is commonly regarded as a feature in support of a diagnosis of desmoplastic melanoma. However, the finding is not specific for melanoma. Herein we report six cases of sclerosing melanocytic nevi with associated lymphocytic aggregates. They occurred in five women and one man, ranging in age from 11 to 61 years. Three lesions were sclerosing Spitz nevi; one was an amelanotic sclerosing blue nevus, one an acquired intradermal sclerosing nevus, and one was a congenital compound melanocytic nevus with sclerosis of its dermal component. The lesions were interpreted as benign, i.e. melanocytic nevi, because of their histopathologic attributes (symmetric silhouette, benign cytologic features) and results from immunohistochemical studies (all lesions strongly expressed Melan-A and p16) and fluorescence in situ hybridization ( FISH). Three lesions tested by FISH lacked copy number changes of 11p, 6q or 6p. None of the lesions recurred. The cases highlight that contextual information is essential for the diagnosis of desmoplastic melanoma and sclerosing nevus. The presence of lymphocytic aggregates per se does not prove that a sclerosing melanocytic proliferation is malignant. [ABSTRACT FROM AUTHOR]

Aim: To evaluate cytokeratin 7 (CK7) immunoreactivity in invasive primary cutaneous squamous cell carcinomas (SCCs). Methods: Twenty-seven primary cutaneous SCCs from 25 patients were evaluated for tumor grade using hematoxylin and eosin-stained slides and for percentage and intensity of immunoreactivity for CK7. All cases exhibited features of SCC with an in situ component. No glandular or tubular differentiation was present. Staining intensity was graded on a scale of 0–3, with 0 indicating no reaction. Of immunoreactive cases, percentage of tumor staining and distribution of immunoreactivity was documented. Results: Six of 27 SCCs (22%) exhibited immunostaining for CK7. Of those cases, three were poorly differentiated, exhibiting 2 to 3+ intensity in 5–15% of cells. Two were poorly differentiated, with 2 to 3+ intensity in 30–60% of cells. The remaining immunoreactive tumor was moderately differentiated, with 1+ intensity and 5% staining in an area of microinvasion. Conclusion: A subset of cutaneous SCCs, in particular, poorly differentiated tumors, may show focal-to-partial immunoreactivity for CK7. This is important to bear in mind when immunohistochemistry is used to distinguish SCC from simulants, such as porocarcinoma, or other adnexal carcinomas with squamous metaplasia. Pulitzer M, Desman G, Busam KJ. CK7 expression in primary cutaneous squamous cell carcinoma. [ABSTRACT FROM AUTHOR]

Background: Longitudinal melanonychia (LM) is characterized by the appearance of a longitudinal pigmented band in the nail plate. Melanonychia can occur from many causes, including racial predisposition, trauma, drugs, pregnancy, Addison disease, Peutz- Jeghers syndrome, Laugier-Hunziker syndrome, Bowen disease, onychomycosis, benign nail matrix nevi, and melanoma. Objective: We present a case of diffuse melanonychia developing several months following Mohs surgery for a human papillomavirus-induced recurrent squamous cell carcinoma in situ of the nail bed. Conclusions: This case illustrates the diagnostic dilemma in determining the etiology of the melanonychia and considers the differential diagnosis. [ABSTRACT FROM AUTHOR]

Examination of Mohs surgery frozen sections may lead to discovery of incidental benign neoplasms such as syringomas.An unusual occurrence of numerous subclinical syringomatous proliferations discovered during Mohs surgery for a basal cell carcinoma that posed a diagnostic and management dilemma is reported.Clinical records and histologic sections are examined.Multiple syringomatous proliferations were noted around a basal cell carcinoma during Mohs surgery. A few foci were atypical appearing and focally extending into the deep dermis causing a diagnostic dilemma. All atypical syringomatous proliferations were excised. Evaluation of final Mohs margins by permanent sections and biopsies of normal-appearing facial skin showed multiple benign syringomas.Although solitary subclinical syringomas have been described in association with basal cell carcinomas, the occurrence of multiple syringomas and syringomatous proliferations has not been previously reported. Dermatologists should be aware of the existence of this phenomenon and consider permanent section evaluation to better determine nature of unusual incidental tumors identified in frozen sections during Mohs surgery.SNEHAL P. AMIN, MD, ALYSA R. HERMAN, MD, KLAUS J. BUSAM, MD, DANA L. SACHS, MD, AND KISHWER S. NEHAL, MD HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS. [ABSTRACT FROM AUTHOR]