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Cutaneous granular cell tumors (GCTs) are rare tumors that typically exhibit benign clinical behavior and are likely of Schwann cell origin. Some histologic and immunohistochemical variants of GCTs may present challenges due to infiltrative growth patterns, perineural invasion, and expression of Melan-A. In this case report, we present a 27-year-old male who had previously been diagnosed with a typical GCT on the back a few years ago. The current biopsy from the proximal palm demonstrated a cytologically similar tumor with extensive perineural spread and notable positivity for Melan-A. Although uncommon, these features are consistent with the histological appearances of GCTs. The current views on the histogenesis of GCTs, clinical associations, differential diagnosis with melanoma, and histological criteria for malignant GCTs are discussed. A panel of immunohistochemical stains, including Inhibin-α and preferentially expressed antigen in melanoma (PRAME), is proposed for use in rare instances of Melan-A-positive GCTs., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Bobkova et al.)

Primary gallbladder melanoma (PGM) is a rare malignancy with only sporadic cases reported in the English literature. We performed a systematic review of the cases published in the PubMed, Science Direct and Google Scholar databases with the aim of describing the reported clinicopathologic features of PGM. Thirty-six articles reporting on 39 patients were reviewed. There was a male predominance, with 23 (64 %) of 36 patients being males. The mean age at presentation was 55 ±16 years. Pain in the right upper quadrant was reported in 20/27 (74 %). The average size of the tumor was 3.5 × 1.9 × 1.4 cm. Gallbladder calculi were reported in 7/27 (26 %). A cholecystectomy was performed in 34/38 (89.5 %). Grossly, the tumor mostly (96.5 %) had polypoid appearances and on microscopic examination, the tumor were predominantly comprised of epithelioid cells 12/17 (70.6 %). Mitotic figures and prominent nucleoli were reportedly found in 8/8 (100 %) and 3/3 (100 %) respectively. Junctional melanocytic components were present in 13/21 (61.9 %). Tumor cells were reportedly immunoreactive for S-100 and HMB-45 in all tested cases. Metastasis were reported in 25/36 (69.4 %), with lymph nodes being the most common site (n = 8), followed by brain (n = 6) and liver (n = 4) for metastasis. At a mean follow-up period of 19 +/- 3 months, 16 (48.5 %) of the 33 patients with available survival data were alive and 17/33 (51.5 %) were dead of disease. There is a lack of unified criteria for the diagnosis of PGM, and future studies should aim to resolve this., Competing Interests: Declaration of competing interest None., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Pathologists face ongoing challenges distinguishing between benign and malignant melanocytic tumors. PRAME (PReferentially expressed Antigen in Melanoma) has a demonstrated value distinguishing between these types of lesions. However, the sensitivity of single immunohistochemistry is variable. HMB-45 is another valuable marker, but on its own, has a limited ability in setting of primary melanocytic tumors. This study sought to evaluate the diagnostic potential of a dual panel combining PRAME and HMB-45 in the assessment of primary melanocytic tumors., Methods: 259 tumors, of which 141 were benign nevi, 31 dysplastic nevi (either low- or high grade dysplasia), and further 87 malignant melanomas, were retrieved from the department's archives and assessed by two experienced dermatopathologists. New sections were stained with PRAME and HMB-45, respectively. For PRAME, a nuclear, and for HMB-45, a cytoplasmic staining, was considered positive and scored as described in the literature on a scale from 0 to 4+. Only dermal component was assessed on HMB-45 stain., Results: PRAME was diffusely expressed in only 1 benign nevus, with focal expression in further 28 compared to 22 diffusely and 103 focally HMB-45-positive benign nevi. 5 high-grade dysplastic nevi showed diffuse PRAME expression in epidermal component, with varying degree of positivity in adjacent dermal compartment, and further 8 dysplastic nevi showed only focal expression. HMB-45 was diffusely expressed in only 2, with focal expression in 23, and no apparent positivity in remaining 6 dysplastic nevi. In invasive melanoma group, PRAME stained >75 % cells in 64/87 tumors, however, 10/87 melanomas were completely negative. HMB-45 was captured diffusely in 49/87 melanomas, 32 showed patchy expression, and 6 tumors were blank negative. Diffuse 4+ PRAME positivity showed superior sensitivity and specificity of 73,6 % and 96,5 %, respectively, compared to HMB-45, 56,3 % and 86,0 %, respectively. No nevi showed double 4+ positivity, however, the sensitivity for double positivity was only 49,4 %., Conclusion: Our results confirm the superiority of PRAME over HMB-45 in the differential diagnosis of melanocytic tumors. However, combined staining can significantly increase specificity, rendering a benign diagnosis more unlikely in a double 4+ diffuse positivity setting., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Lymphangioleiomyomatosis (LAM) is a rare, slow-growing metastasizing neoplasm in which smooth muscle-like cells infiltrate the lung parenchyma and cause cystic lung damage. The common early symptoms include shortness of breath, pneumothorax, and chest pain. Lymphangioleiomyomatosis mainly involves the lungs, kidneys, and lymph nodes. This study reviews the characteristics of lymphangioleiomyomatosis to identify any possible changes in the prevalence of symptoms of the disease. We conducted a literature review of case reports on lymphangioleiomyomatosis from PubMed and Google Scholar. Variables of interest were age, gender, symptoms, vitals, immunostaining, and radiological findings. Data were transferred to an Excel spreadsheet (Microsoft Corporation, Redmond, WA), and mean, median, standard deviation, frequencies, and proportions were calculated using R version 1.1.456 (RStudio: Integrated Development for R. RStudio, PBC, Boston, MA). Lymphangioleiomyomatosis is a rare case and so not much of the literature could be found online. Thirty-three case reports were included in this study, and females accounted for 78.78% of the presentations. The average age was 38 years, SD 14.41 years. Shortness of breath was the most frequent symptom (60.6%), followed by pneumothorax (57.57%), chest pain (42.42%), cough (24.24%), and pleural effusion (1.25%)., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Shah et al.)

Melanocytic skin tumours have been rarely described in pet rabbits, and exposure to UV light in sparsely haired areas has been hypothesised to play a cancerogenic role. Here, we describe a case of cutaneous malignant melanoma arising from the skin of the scrotum in an 8-year-old male wild rabbit, with testicular metastases as an unusual metastatic site for melanoma reported in humans to date. The tumour was nearly 5 cm in size, firm, and highly pigmented, with multifocal superficial ulcerations and large areas of intratumoural necrosis. The adjacent testis was 1.5 cm, multinodular, and black, obscuring tissue morphology. Histologically, the dermis was expanded by an infiltrative, densely cellular neoplasm composed of nests and sheets of polygonal to spindle neoplastic melanocytes, supported by scant fibrovascular stroma. Neoplastic cells showed intermediate N/C ratio, moderate basophilic cytoplasm, often obscured by abundant brownish granular pigment, and eccentric nuclei with prominent nucleoli. Cellular pleomorphism and nuclear atypia were severe, and high mitotic activity was observed. Diffuse dermal lymphovascular invasion was also observed. The testis was delimited by a thin tunica albuginea, and the parenchyma was largely obscured in its morphology by densely packed neoplastic cells. Seminiferous tubules, lined with a thin basement membrane and containing neoplastic and scattered spermatogenic cells, were occasionally observed. Neoplastic cells within the skin and the testis were positive for HMB-45, Melan-A, and S-100. The growing popularity of rabbits as pets allows for a greater ability to accumulate data on the spontaneous occurrence of tumours in these animals. Furthermore, descriptions of the biological aspects of spontaneously occurring tumours may serve to improve current knowledge in animal species and humans in which the same neoplasm may occur.

Background: Renal angiomyolipomas (AMLs) are rare, benign mesenchymal tumors of the kidney. Asian data on the prevalence of the subtypes of AMLs and their association with tuberous sclerosis are sparse prompting us to evaluate the clinicopathological characteristics of these tumors., Materials and Methods: We included cases diagnosed from 2001 to 2021 extracting demographic details, clinical presentation, syndromic association with tuberous sclerosis, and preoperative clinicoradiological features from the electronic medical records., Results: Ninety-five cases of adult renal AML were diagnosed among 2402 renal tumors, a prevalence of 3.95%. Forty tumors (42%) were detected incidentally; two patients had life-threatening retroperitoneal hemorrhage. Tuberous sclerosis complex (TSC) was associated with ten cases (10.5%). These patients were a decade younger than those in the non-TSC group ( P = 0.008) and had bilateral, multiple, and larger tumors ( P = 0.0009, 0.001, and 0.047, respectively). Microscopically, classic and epithelioid subtypes were seen in 87 (91.6%) and 8 cases (8.4%), respectively. Hemorrhage was more common in the epithelioid subtype ( P = 0.13). HMB-45, melan-A, and smooth muscle actin immunohistochemistry were useful in cases which lacked the prototypical classic histology and for confirming a diagnosis of epithelioid AML., Conclusions: The prevalence of renal AML in our series was four times higher, and the mean age at diagnosis was a decade earlier than that reported in Western literature but similar to data from two Asian countries. Similar studies from other countries will help ascertain if these differences in prevalence can be attributed to ethnic differences., Competing Interests: There are no conflicts of interest., (Copyright: © 2022 Urology Annals.)

Background: Updates of treatment methods of stable vitiligo are needed to give better outcomes with a shorter duration of treatment., Objective: To test the effect of transdermal 5-fluorouracil (5-FU) delivery using fractional CO 2 (FrCO 2 ) laser versus intralesional 5-FU injection, with narrow-band type ultraviolet B (UVB) (NB-UVB) therapy after both, in the treatment of stable vitiligo., Patients and Methods: The present study comprised 40 patients with nearly symmetrical stable vitiligo lesions. The left side was treated with FrCO 2  laser followed by topical 5-FU (FrCO 2  + 5-FU), while the right side was treated with 5-FU intradermal injection. Both procedures were done at 2-week intervals for 3 sessions followed by 24 sessions of narrow-band UVB for both sides., Results: Repigmentation was demonstrated on the left side of 90% of patients and the right side of 85% of patients. As much as >50% improvement was demonstrated on the left side of 50% of patients, and the right side of 55% of patients. Intralesional 5-FU showed a statistically significant difference in repigmentation compared to FrCO 2  + 5-FU., Conclusion: Both 5-FU injection and FrCO 2  + 5-FU were effective therapeutic modalities for vitiligo. Patients were more compliant with FrCO 2  + 5-FU., (© 2021 Wiley Periodicals LLC.)

Background: Anorectal melanoma is a rare disease with a poor prognosis. Symptoms are often nonspecific, which complicates preoperative diagnosis. Here, we describe the establishment of MELS, a new anorectal melanoma cell line derived from resection of a rectal tumor in a 40-year-old Japanese man., Methods: Histological, electron microscopic, and immunohistochemical features of S-100, HMB-45, Melan-A, and NSE positivity of the tumor were typical of surgically resected anorectal melanoma., Results: MELS cells are round or oval and have sharp thorn-like protrusions on some or all cell membranes. The cells form irregular attached colonies with numerous floating cells in two-dimensional culture. Transmission electron microscopy revealed that some MELS cells have cytoplasmic melanosomes. Immunocytochemically, MELS cells and surgical tissues had the same staining pattern. MELS cells had lower growth rates than Caco-2 (a colon adenocarcinoma cell line) and A375 (a cutaneous melanoma cell line) cells. Oxaliplatin and irinotecan were more effective in MELS cells than in Caco-2 and A375 cells., Conclusions: No previous report provided detailed clinical information on an anorectal melanoma cell line. Thus, MELS cells should improve our understanding of the biological characteristics of anorectal melanoma and provide a novel platform for examining the effects of therapies for anorectal melanoma.

Melan-A is one of the most commonly used immunohistochemical assays (IHC) in dermatopathology laboratories to detect the presence and outline the distribution of melanocytes. It is a cytoplasmic stain that detects a melanocyte-specific cytoplasmic protein involved in the formation of stage II melanosomes. Clinically, Melan-A is primarily used to detect and confirm melanocytic tumors although it is also positively expressed in adrenal cortical tumors and sex cord stromal tumors. We found that Melan-A also detected and highlighted Henderson-Patterson bodies of molluscum poxvirus. To determine if other melanocytic markers detect molluscum contagiosum bodies, S-100, HMB-45, MITF, and SOX-10 were also tested. In 15 tested molluscum cases, Melan-A stains were positive in all cases, whereas the other tested melanocytic markers were negative. Our results confirm that Melan-A is very sensitive in detecting molluscum contagiosum bodies and could be clinically useful to supplement the hematoxylin and eosin (H&E) in cases that are very inflamed or only have limited biopsy material.

This study aims to investigate the usefulness of the Melan-A and homatropine methyl bromide-45 (HMB-45) markers in identifying melanocytes and to evaluate cut-off values for the diagnosis of vitiligo. We also aim to identify the role of remaining melanocytes when using HMB-45. We counted and confirmed melanocytes and melanin in the samples using a high-magnification microscope. The Melan-A, HMB-45, and Fontana-Masson staining methods were utilized. Descriptive statistical analysis of quantitative traits was performed. For the comparison of the two diagnostic tools, receiver operating characteristic curve and the area under the curve were evaluated. We found out that there was no significant difference observed between the two methods. The cut-off value is <27 for HMB-45 and <15 for Melan-A per 100 cells in the basal cell layer. Thus, HMB-45 is as useful as Melan-A in the diagnosis of vitiligo., Competing Interests: None., (IJCEP Copyright © 2021.)

Angiomyolipoma (AML) is a mesenchymal tumor commonly found in the kidneys. Extra-renal AML is uncommon and especially rare in the nasal cavity. To our knowledge, fewer than five cases of nasal AML are reported in the United States. We present a case of nasal AML in a 65-year-old man with a history of rhinosinusitis and obstruction of the left nasal cavity. The lesion comprised of admixed spindled smooth muscle cells, mature adipose tissue, and thick-walled blood vessels. Smooth muscle differentiation of the spindled cells was confirmed by expression of smooth muscle actin. Surprisingly, melanocytic markers, such as HMB45, were negative. The histologic features and immunoprofile suggest that nasal AML is pathologically distinct from neoplastic AMLs/perivascular epithelioid cell tumors (PEComas) that typically occur in the kidney. We propose that nasal AML is a hamartomatous lesion rather than neoplastic. Although AML is rare in the nasal cavity, it should be considered in the differential diagnosis of clinically benign nasal masses.

Background: Combination therapies have reported to augment the repigmentation in vitiligo. Microneedling (Mn) facilitates drug delivery across the skin barrier., Objective: To evaluate and compare the efficacy and safety of Mn combined with tacrolimus vs Mn alone or tacrolimus 0.1% ointment for treatment of localized and stable vitiligo., Patients and Method: Ninety patients with vitiligo were randomized into three groups: group I received microneedling with tacrolimus, group II microneedling only both at 2 weeks interval for twelve sessions, and group III applied tacrolimus ointment 0.1% twice daily for 6 months. Skin biopsies were taken at baseline and after treatment., Results: The overall improvement (76.6%) was significantly higher in the combined group compared with other groups. Repigmentation was excellent in 66.6 of group I vs 33.3% in the other two groups (P .03). A highly significant improvement of the extremities was observed in the combined group than in the other groups (P < .001). A fewer number of sessions have reported in the combined group (I) than in the microneedling group (II; P < .001). Immunohistochemical results showed a significantly higher expression of HMB-45 in group I than in other two groups (P .04). Side effects were mild and tolerable in all groups., Conclusion: The combination group has shown promising results over the other two groups., (© 2020 Wiley Periodicals, Inc.)

Background: Primary melanocytic neoplasms in the central nervous system are rare lesions arising from leptomeningeal melanocytes. These lesions produce neural deficits that resemble those of a meningioma or a schwannoma radiologically., Case Description: A tumor around the left S1 root with an extension into the left paraspinal compartment was identified in a 32-year-old female with persistent left leg pain for 6 months. The tumor was hyperintense on T1-weighted image and hypointense on T2-weighted image with a homogeneous enhancement. The clinical features, radiologic presentations, treatment choice, and pathologic characteristic were illustrated. The treatment outcome was compared with those reported in the previous literature. The tumor was en-bloc resected with the S1 nerve root reserved. Grossly, the tumor was a soft, capsulated, well-circumscribed, black pigmented lesion. Immunohistochemistry revealed that the tumor cells were positive for HMB-45, S-100 protein, and vimentin. The patient's symptoms were greatly relieved postoperatively. No signs of local recurrence were observed., Conclusions: Spinal meningeal melanocytoma inside the nerve root is rare and benign. It is difficult to diagnose and often misdiagnosed as schwannoma or meningioma. HMB-45 has been suggested as a significant marker for the diagnosis of meningeal melanocytoma. Complete surgical resection is recommended as the primary treatment. Radiotherapy, chemotherapy, and other treatments can be selected as adjuvant therapies, but their effects are controversial. The recurrence and metastasis rates also remain unclear., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Disseminated tumor cells (DTCs) are studied as a prognostic factor in many non-hematopoietic tumors. Melanoma is one of the most aggressive tumors. Forty percent of melanoma patients develop distant metastases at five or more years after curative surgery, and frequent manifestations of melanoma without an identified primary lesion may reflect the tendency of melanoma cells to spread from indolent sites such as bone marrow (BM). The purpose of this work was to evaluate the possibility of detecting melanoma DTCs in BM based on the expression of a cytoplasmatic premelanocytic glycoprotein HMB-45 using flow cytometry, to estimate the influence of DTCs' persistence in BM on hematopoiesis, to identify the frequency of BM involvement in patients with melanoma, and to analyze DTC subset composition in melanoma. DTCs are found in 57.4% of skin melanoma cases and in as many as 28.6% of stage I cases, which confirms the aggressive course even of localized disease. Significant differences in the groups with the presence of disseminated tumor cells (DTCs + ) and the lack thereof (DTC - ) are noted for blast cells, the total content of granulocyte cells, and oxyphilic normoblasts of erythroid raw cells., Competing Interests: The authors declare no conflict of interest.

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal tumors that can affect any part of the body. They can be sporadic or arise in the setting of tuberous sclerosis (TSC). In this article, we report a series of three hepatic and two pancreatic PEComas diagnosed preoperatively with ultrasound-guided fine needle aspiration (FNA). All patients were female (age range 28-70), had no personal history of TSC and presented with a single, localized painless mass. Rapid on-site evaluation (ROSE) of cytologic samples was performed for all cases to evaluate for cellular content and adequacy of specimens. Direct smears and cell block preparations revealed a proliferation of medium to large polygonal epithelioid cells, with abundant eosinophilic and vacuolated cytoplasm, arranged in sheets and nests. On immunohistochemistry (IHC), neoplastic cells showed co-expression of melanocytic and smooth muscle markers and a diagnosis of PEComa was rendered. PEComas of the pancreas and liver are rare neoplasms, but should always be considered when examining "clear cell" neoplasms, especially in young female patients. If good quality cytologic samples are obtained by FNA, a correct diagnosis can be achieved with the help of IHC. This is of particular importance in order to plan adequate surgical strategy and to avoid overtreatment., (© 2018 Wiley Periodicals, Inc.)

Aim: To study the clinicopathologic characteristics of perivascular epithelioid cell tumor (PEComa) in the liver and to improve the understanding and diagnosis of this tumor. Methods and results: 13 cases of primary liver PEComa were retrieved from our hospital from January 2007 to September 2017. The clinicopathologic features and the computer tomographic (CT) or/and magnetic resonance imaging (MRI) tests of each case were retrospectively reviewed. All 13 patients were female, with ages ranging from 22 to 72 years (median, 35 years). The sizes of the tumor ranged from 1.0 to 19.8 cm. Histologically, the tumors were comprised of polygonal cells with clear to granular eosinophilic cytoplasm and were accompanied by positive immunohistochemical expression of HMB-45 and/or Melan-A. 6 cases showed moderate cytological atypia. Hemorrhage was present in 7 of 13 cases, and necrosis in 2 cases. Mitoses were scant, averaged from 0 to 1/50 high-power fields in every case. No vascular invasion was present in any case. Follow-up data were obtained from 9 of 13 cases, and none showed any evidence of tumor recurrence or metastasis. Conclusions: There are no specific symptoms of hepatic PEComa, and the preoperative imaging tests are also insensitive. In view of diverse histological growth patterns with atypical cell features in part of cases, the possibility of PEComa should be considered whenever unfamiliar hepatic tumors are encountered. Immunoreactivity for HMB-45, MelanA, and SMA, especially HMB-45, is very useful for the diagnosis of this tumor., Competing Interests: None., (IJCEP Copyright © 2018.)

Renal angiomyolipoma (AML) is a rare benign neoplasm of mesenchymal origin. AML incidence varies from 0.3 to 5%, while women suffer four times more often than men. In most cases, renal AML measures less than 4 cm, is asymptomatic and detected accidentally with computed tomography or ultrasound. A histological variant of AML need to be verified to choose management strategy and reduce the risk of complications. Histological and immunohistochemical assessment of biopsy and surgical specimens has an essential diagnostic value in determining the type and subtypes of renal neoplasms and the risk of malignancy. The study aimed to investigate pathomorphological and prognostic features (immunohistochemical characteristics) of renal AML., Materials and Methods: Patients (n=42) with CT-detected renal neoplasms underwent partial nephrectomy. The majority (n=34) of patients was admitted to the hospital urgently, often without symptoms (n=23). The surgical specimens studied were examined using light microscopy and immunohistochemistry analysis with primary mouse monoclonal antibodies to HMB-45, Melan-A, -SMA, S-100 and SC (Novocastra, UK)., Results: All specimens showed morphological characteristics typical of AML and a positive response to antibodies against HMB-45 (ve +/3; 99.6+/-0.3%), Melan-A (ve + / 2, 89.6+/-4.3%) and SMA (ve + 2; 70.1+/-2.9%) and exhibited no staining with antibodies against S-100 and SK., Conclusion: Morphological study of renal AML shows that the tumor is benign, therefore partial nephrectomy, in our opinion, should be considered as an alternative to radical nephrectomy, including for sporadic giant renal AML.

Angiomyomatous hamartoma of lymph nodes (AMH-LN) is an uncommon benign proliferation of smooth muscle, blood vessels, collagenous stroma, and adipocytes, most commonly affecting inguinal LN. A similar constellation of cell types constitutes various members of the perivascular epithelioid cell tumor (PEComa) family, including lymphangioleiomyomatosis (LAM), which can involve LN in women. Because some LN-LAM patients have tuberous sclerosis complex and/or other PEComa family lesions, it is clinically relevant to distinguish LN-LAM from AMH-LN. Given their similar features, however, the possibility that AMH-LN is a morphologic variant of LN-LAM merits inquiry. The dual melanocytic and myoid immunophenotype distinguishes the PEComa family from its mimics. Cathepsin K has recently emerged as a more sensitive marker for the PEComa family than HMB-45, which can be weak and focal, but cathepsin K has not been studied in AMH-LN. This study evaluated 21 AMH-LNs for clinical, morphologic, and immunophenotypic features of LN-LAM. None (0/21) had tuberous sclerosis complex or PEComas. Thirteen (62%) were male, unlike LN-LAM, which is restricted to women. All cases exhibited intraparenchymal proliferation of variable-sized, thick-walled blood vessels within collagenous stroma containing a sparse to focally cellular population of haphazardly distributed smooth muscle cells. Admixed adipocytes were commonly present. None exhibited classical features of LN-LAM such as subcapsular localization, extranodal extension, intralymphatic growth, compact nests, branching lymphatic channels, plump cell shape, or foamy/clear cytoplasm. None exhibited any staining for cathepsin K, HMB-45, or microphthalmia transcription factor. There is no clinical, morphologic, or immunohistochemical evidence to suggest that AMH-LN is a variant of LN-LAM., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Mucoepidermoid carcinoma (MEC) is the most common malignant neoplasm of the salivary gland. Albeit common, histologic variants have rarely been noted in MEC. Here, we report a 49-year-old man with a sublingual gland tumor. Histologically, the tumor was composed of spindle cells arranged in interlacing fascicules or globular nests. A few bland small glands containing mucous cells were also scattered. The spindle tumor cells completely lacked immunoreactivity for cytokeratin, and exhibited immunoreactivity for vimentin, S-100, HMB-45, Melan A, and SOX10. The tumor was initially suspected to be clear cell sarcoma, malignant melanoma, or perivascular epithelioid cell tumor with a few entrapped nonneoplastic duct epitheliums. However, reverse-transcription polymerase chain reaction revealed the CRTC3-MAML2 fusion gene product diagnostic of MEC. In fact, a very minor component of the epithelial cells was reminiscent of conventional MEC, whereas major spindled tumor cells possessed markedly altered differentiation. This is the first case report of MEC with extensive spindled morphology and melanocytic marker expression., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Hepatic perivascular epithelioid cell neoplasm (PEComa) is a rare type of neoplasm derived from mesenchymal tumors that is often misdiagnosed as hepatocellular carcinoma (HCC), hepatic hemangioma or other liver malignancies. The clinical and histological characteristics of PEComa have yet to be fully documented. To optimize the diagnosis and treatment of the disease, a retrospective analysis was performed to investigate the clinicopathological characteristics of 7 patients diagnosed with hepatic PEComa in the Sun Yat-Sen Memorial Hospital between January 2004 and December 2015. Briefly, all the patients lacked specific symptoms, and a serological examination provided no further useful information. Additionally, non-specific imaging manifestations were observed. Microscopically, detection of epithelioid or spindle-shaped cells with adipocytes was suggestive of the disease, and an analysis of biomarkers, including the monoclonal antibody HMB-45, the melanocytic differentiation marker, Melan-A, and smooth muscle α-actin (SMA), helped to confirm the diagnosis. Regarding the treatment, 6 patients (85.7%) received surgical resection procedures, and 1 patient (14.3%) was admitted for tumor arterial embolization and percutaneous microwave coagulation therapy. After a follow-up period of 12-20 months, no recurrence was observed. Taken together, hepatic PEComa should be suspended in patients with a liver tumor with asymptomatic manifestation and normal serological test results. In imaging studies, hepatic PEComa was able to mimic HCC, hepatic hemangioma and metastatic tumor, although the mass did not invade the adjacent organs and vessel. The definitive diagnosis was made on the basis of the typical morphological features and notable markers of the tumor tissue. It is recommended that patients with PEComa in a benign pattern deserve serial imaging follow-up, but surgery is indicated in patients suffering from large tumors (>5 cm), or progressive enlargement or malignant tendency.

Perivascular epithelial cell tumors (PEComas), firstly described by Bonetti in 1992, are a family of mesenchymal tumor composed of perivascular epithelioid cells having epithelioid or spindle morphology and exhibiting melanocytic and myogenic immunoreactivities. We herein described a 61-year-old woman who presented with epigastric pain. Preoperative imaging studies showed that 7-cm-sized mass was located in pancreatic head and body, and pancreaticoduodenectomy was performed. Histological findings showed that the tumor was composed of clear epithelioid cells with abundant glycogen granules, which grew in a nested and alveolar pattern around blood vessels. The tumor cells showed immunoreactivities for HMB-45 but did not express epithelial or endocrine markers. These histological features indicated those of PEComa. This report underlines that we should recognize PEComa as a preoperative differential diagnosis of pancreatic tumors.

Objectives: Histologic and molecular heterogeneity is well recognized in malignant melanoma; however, the diversity of expression of new and classic melanoma markers has not been correlated in serial sections of metastases., Methods: We examined and correlated the expression of microphthalmia transcription factor (MITF) with its transcriptional targets, including melastatin (MLSN1/TRPM1), pigment epithelium-derived factor (SERPINF1/PEDF), SILV/PMEL17/GP100 (human melanoma black 45 [HMB-45]), and melanoma antigen recognized by T cells 1 (MART-1)/MLANA, in 13 melanoma metastases in lymph nodes of 13 patients. The expression levels and patterns of marker expression were recorded by a semiquantitative, 4-point ordinal reactivity method., Results: Our results showed a consistently robust and diffuse expression of MITF protein in 12 (92%) of 13 metastatic tumors compared with variable expression of MLSN1 (46%) messenger RNA or PEDF (75%), HMB-45 (54%), and MART-1 (46%) proteins., Conclusions: Overall, in melanoma lymph node metastases, MITF protein expression was not tightly correlated with its gene targets. Moreover, the immunoreactivity for MITF, compared with MART-1 and HMB-45, was retained, supporting immunohistochemical detection of MITF as a more sensitive method of detecting metastatic melanoma., (© American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Perivascular epithelioid cell tumor (PEComa) of the pancreas is an unusual tumor deriving from mesenchyma. This paper described a case of pancreatic PEComa, which was initially suspected as neuroendocrine carcinoma by biopsy, and therefore surgical treatment was recommended due to undetermined diagnosis. Examination of the surgical specimen under a microscope showed that the tumor cell's morphology was epithelioid or spindle-shaped, and ranged in a nested pattern. Additionally, these cells had a large extent of acidophilic cytoplasm, no mitotic figures, and expressed HMB-45, melan-p, and smooth muscle actin immunohistochemically. Pathological examination indicated that PEComa originated from the pancreas, but symptoms related to tuberous sclerosis were absent. Since PEComa is extremely rare in the pancreas, it is likely to be ignored in differential diagnosis. In conclusion, our article highlighted the clinicopathological features of PEComa, and we conducted a literature review focusing on PEComa so as to deepen the understanding of this tumor type.

Introduction: Perivascular Epithelioid Cell tumor (PEComa) is a rare neoplasm of mesenchymal origin, with the uterus being the most common site of appearance, regarding the female genital tract., Case Report: We present two cases of PEComas of the uterus in patients aged 57 and 42-years-old, presented to our department with palpable abdominal masses and abnormal vaginal bleeding. During follow up period, both patients are free of recurrent disease one and two years after surgery, respectively, without receiving any adjuvant treatment., Conclusions: PEComa of the female gynecological tract is a rare entity presenting with variable symptoms and different prognosis for each individual case. The diagnosis is based on histopathology and immunohistochemistry reports and the optimal treatment is the surgical resection of the tumor., (Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Amelanotic malignant melanoma (AMM) is rare in the oral region. The present study examined the clinical features of this tumor in an attempt to establish diagnostic criteria. The expression of three melanocytic differentiation markers, HMB-45, S-100 and Melan-A, was also measured in primary oral AMMs in order to determine whether the markers could be used to diagnose primary oral AMMs and to find out which marker was the most sensitive. It may be particularly difficult to correctly diagnose AMM that lacks a radial growth phase without immunohistochemical assistance. In the present study, mixtures of polygonal and spindle cells at different ratios were observed in the tumors with and without a radial growth phase. Immunohistochemistry was used to examine the HMB-45, S-100 and Melan-A expression in the formalin-fixed paraffin-embedded specimens of primary oral AMMs. Comparison of staining intensities (SIs) and labeling indices (LIs) of the markers was also performed. The immunostaining results revealed that the SI of Melan-A was significantly higher than that of S-100 (P=0.0011). HMB-45, S-100 and Melan-A also exhibited high positive rates and LIs in AMMs and, therefore, may be good markers for the immunohistochemical diagnosis of primary oral AMMs. Furthermore, Melan-A may be a more sensitive marker than S-100 and HMB-45, as it has a higher SI.

We are reporting a case of superficial spreading melanoma (SSM) on left palm of a 37-year-old pregnant housewife. She had a small acquired melanocytic nevus on her left palm since childhood, which changed its consistency and color in the last 4 months. Dermoscopy of the lesion indicated malignant changes. The lesion was managed surgically using split-thickness skin graft. The histopathology report was suggestive of SSM with positive HMB-45 cells. SSM is very rare on the acral site, and it is very difficult to differentiate it from acral lentiginous melanoma. The rarity of the site (acral nonchronic sun damage) with evolution during pregnancy and importance of management approach are reasons for publishing this case.

Primary or metastatic melanocytic tumors in the sellar region are rare and can pose a diagnostic challenge. Here we describe a case of a 74-year-old man who underwent radiological investigations for a transient episode of blurred vision. Based on the clinical and endocrinological findings and MRI results, the patient was assumed to have a clinically non-functioning pituitary macroadenoma, which was followed-up over a 2-year period. He did not have any endocrine symptoms or progressive visual deterioration, and no history of past malignancy, including melanoma. Endocrinological investigation was unremarkable; blood hormone levels were within the normal ranges except for low serum total testosterone and bioavailable testosterone levels without symptoms of hypogonadism. The longitudinal MRI follow-up demonstrated a gradual increase in the size of the tumor over the course of 11 months. For this reason, the patient underwent surgery. Pathologic examination including histology, immunohistochemistry and electron microscopy achieved the correct diagnosis of melanocytic tumor of the sellar region morphologic examination is essential in the diagnosis of melanocytic tumors. Hmb-45 is an important diagnostic biomarker in melanocytic lesions. The use and exploration of miRNA, Ki67 and osteopontin are important in understanding the genesis, progression, and prognosis in treatment of patients with melanocytic tumors., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

We report a case of angiomatoid melanoma on the right thigh of a 59-year-old man. The histologic growth pattern of the tumor mimicked vascular proliferation, and the cells lining the pseudovascular spaces were positive for protein S-100, HMB-45, and MITF-1. The differential diagnosis is with angiosarcoma and pseudovascular adenoid squamous cell carcinoma. The case we present is the fifth reported to date., (Copyright © 2014 Elsevier España, S.L.U. y AEDV. All rights reserved.)