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Emerging evidence is implicating stem cells in the pathogenesis of different cutaneous neoplasms. The immunohistochemical use of stem cell markers has facilitated stem cell identification. While few studies have examined the expression of cytokertatin (CK)15 and cytokeratin (CK)19 in basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), only rarely have nestin expression been examined in these two malignancies. Furthermore, stem cell marker expression, to the best of our knowledge, has not been examined in Merkel cell carcinoma (MCC). In this study, we examined the expression of stem cell markers CK15, CK19 and nestin in 51 overall cases (11 cases of MCC and 20 cases each of BCC and SCC) retrieved from the pathology files of Skin Pathology Laboratory, Boston University School of Medicine. Cytokeratin 15 immunoreactivity was observed in 30% of BCC cases and only a single (5%) SCC case, while all MCC cases were negative. While 60% of BCC cases and 30% of SCC cases stained positively with CK19, all MCC cases showed positive immunostaining in a dot-like pattern. While negative in BCC and MCC, nestin expression was interestingly seen in 45% of SCC cases. Our study described the expression profiles of stem cell markers CK15, CK19 and nestin in BCC, SCC and MCC. In addition to confirming results of the previous reports, our study also showed positive nestin expression in around half of SCC cases, which adds this malignancy to the cutaneous tumours that have been so far reported to exhibit nestin expression. [ABSTRACT FROM AUTHOR]

Describes a solitary cutaneous lesion as the first evidence of disseminated neoplastic disease. Cutaneous involvement in anaplastic large cell lymphoma that may be in form of primary cutaneous disease or secondary to involvement by systemic disease; Histology of the lesion; Implications on dermatology, venereology and leprology.

We examined the effects of daily topical application of 0.05% tretinoin cream on photodamaged Caucasian facial skin by electron microscopy. Specimens obtained pretreatment, after 6 and 12 months of tretinoin therapy (20 patients), and after 6 months of vehicle treatment (5 patients) were compared in a blinded fashion, with special attention to the dermoepidermal junction and papillary dermis. Baseline specimens disclosed various degrees of damage including reduplication of basal lamina, smudging and sparsity of collagen fibers, and nodular arrangement of degenerated microfibrils in the papillary dermis. No significant changes were observed at 6 months in the papillary dermis of either tretinoin- treated or vehicle-treated patients. After 12 months of tretinoin treatment, however, disorganized collagen fibers, which were conspicuous in 11 patients at baseline, were replaced by new well-organized collagen fibers in a wavy pattern in 6 patients. In addition, the amount of nodularly degenerated microfibrillar material decreased in 15 of 18 patients with this finding at baseline. In contrast, no significant change was noted in the number of anchoring fibrils per unit length of the lamina densa. These observations provide further evidence that topical treatment with 0.05% tretinoin produces papillary dermal reconstruction, for which more than 6 months of application were required. [ABSTRACT FROM AUTHOR]

Histologic studies have become increasingly important in recognizing morphologic differences in photoaged versus intrinsically aged skin. Earlier histologic studies have attempted to evaluate these changes by examining anatomical sites which are not comparable, such as face and buttocks. As part of a multicenter study, we have quantitatively examined a panel of 16 histologic features in baseline facial skin biopsies from 158 women with moderate to severe photodamage. When compared to the postauricular area (photo protected), biopsies of the crow's feet area (photo exposed) had a twofold increase in melanocytes and a statistically significant increase in melanocytes and a statistically significant increase in melanocytic atypia (p <.0001) and epidermal melanin (p <.0001). Other epidermal changes included reduced epidermal thickness (p <.01), more compact stratum corneum (p <.0001) and increased granular layer thickness (p <.0001) in the crow's feet skin. There was increased solar elastosis (p <.0001), dermal elastic tissue (p <.0001), melanophages (p <.0001), perivascular inflammation (p <.05) and perifollicular fibrosis (p <.01) but no change in the number of mast cells or dermal mucin in the photo exposed skin. Our data document quantitative differences in photoaged versus intrinsically aged facial skin and provides the groundwork for future studies to evaluate the efficacy of new treatments for photoaged skin. [ABSTRACT FROM AUTHOR]

Metaplastic synovial cyst, a recently described entity, is histologically characterized by a cystic cavity lined by metaplastic synovial tissue that is often hyperplastic and protrudes into its lumen as villous structures. Clinically, these lesions resemble suture granuloma and develop at the site of previous surgical trauma. We have studied 4 cases of this unusual entity and have investigated the immunohistochemical profile in an effort to determine the nature and derivation of their lining tissue. One of our cases is unique since the lesion was associated with a basal cell carcinoma. A history of previous surgery was noted in one, and history of trauma in 2 of the 4 cases. Our immunohistochemical observations confirmed a mesenchymal derivation for the "synovial like villous structures" but non-availability of a specific "synovial" marker does not permit us to conclude with certainty the synovial nature of the metaplastic tissue. Cutaneous metaplastic synovial cysts are unique lesions which deserve attention and should be included in the differential diagnosis of cutaneous cysts. [ABSTRACT FROM AUTHOR]

Extravasation of doxorubicin in skin and tissue causes necroses and ulceration. These ulcers form slowly and heal with great difficulty. The cause of ulcernation is not known. Histologic changes in two patients suggest that an exaggeration of interface dermatitis like epidermal changes may be enhanced or complicated by ischemic changes caused by thrombosis of the venous tributaries at the site of the intravenous infusions. Squamous syringometaplasia seen in both cases can be confused with squamous cell carcinoma. Dermal changes mimic those seen in radiation injury. [ABSTRACT FROM AUTHOR]

Apocrine hidrocystomas are often pigmented clinically. The cause of this pigmentation is not known. A case of pigmented apocrine hidrocystoma is presented with evidence of melanin as the underlying mechanism of the pigmentation. Review of an additional 150 cases suggests that this is rare. The Tyndall effect, analogous to that seen in blue dome cysts of fibrocystic disease of the breast may be the likely explanation of the pigmentation seen clinically in most cases of apocrine hidrocystomas. [ABSTRACT FROM AUTHOR]

We report pigmented lesions in 2 white male patients, which were clinically diagnosed as superficial spreading malignant melanoma and histologically showed combined features of superficial spreading malignant melanoma in suit and pigmented basal cell carcinoma. The significance of this association is not known but is most likely very rare. [ABSTRACT FROM AUTHOR]

Light and electron - microscopic studies were performed on the amelanotic and adjacent normal-appearing skin in patients with vitiligo. The amelanotic skin revealed complete loss of pigment and absence of melanocytes. In addition to severe egenerative changes of melanocytes. Varying degree of damage was also seen in the keratinocytes of normal-appearing skin adjacent to amelanotic skin. [ABSTRACT FROM AUTHOR]

A 36-year-old Caucasian man presented with chronic, slightly erythematous, scaly plaques of 6 year duration. Some improvement was noticed after treatment with topical steroids. Differential clinical diagnoses included psoriasis and eczema. A biopsy revealed psoriasiform changes with "fatty vacuoles" replacing the papillary dermis. The histogenesis of these findings is unknown. Even though small foci of fatty vacuolization have been observed in association with heavy inflammatory infiltrates in skin, this is the first reported case of massive fatty infiltrates in a non-neoplastic disorder of the skin associated with only sparse inflammatory infiltrate. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to article about keratin 16 expression in epidermal melanocytes by Ramos and colleagues in the 2009 issue.

Background: Cellular neurothekeoma is a relatively rare, benign cutaneous neoplasm, which usually presents as a solitary papule or nodule involving the head and neck area of young adults. Multiple neurothekeomas have not, to date, been known to occur. Methods: We report a 30-year-old, otherwise healthy, male who presented with multiple neurothekeomas (15) in the head and neck area over a period of 12 years. Results: While the unifying feature of all biopsied (10 of 15) lesions was the presence of epithelioid cells - the lesions differed in their cellularity and the degree of sclerosis of the stromal component. Antigenic profiling of the lesional cells revealed expression of vimentin, NKI/C3, PGP 9.5, factor XIIIa and CD68 but not S100, HMB45, MelanA, EMA, MSA, desmin, CD57 or NGF-R. Conclusions: This case report is the first to document the occurrence of multiple cellular neurothekeomas. An unusual histologic feature of some of the biopsied lesions was the presence of a markedly sclerotic stroma. [ABSTRACT FROM AUTHOR]

Intraepidermal nerve fibers were studied by electron microscopy in chronically photodamaged preauricular skin and in paired sun-protected postauricular sites of 20 Caucasian women aged 56-70 years. As previously reported, basal keratinocytes in the sun-exposed skin showed various degrees of degenerative changes including intracellular vacuolar structures and widened intercellular spaces. Neurites were frequently closely apposed to basal keratinocytes in preauricular sun-exposed skin, but were observed less than 10% as often in sun-protected postauricular skin. When degree of epidermal photo-damage was quantified by means of the number of degenerated keratinocytes pet 100 keratinocytes in the basal layer, the number of intraepidermal nerve fibers was significantly correlated by linear regression analysis to the severity of epidermal photodamage (t=0.913) independent of anatomical sites. These results demonstrate for the fist time a correlation between degree of epidermal innervation and chronic photodamage and suggest the possibility of neural involvement in the pathophysiology and/or repair of photodamaged skin. [ABSTRACT FROM AUTHOR]

Melanoma is a malignant tumor with a varied histologic appearance. Melanoma composed of spindle cells may include desmoplastic and neurotropic melanoma can be difficult. Although S100 protein stains a majority of these melanomas, the staining may be weak or focal. HMB-45, a more specific marker of melanoma, is frequently negative in desmoplastic and neurotropic melanoma. In order to aid the identification of desmoplastic and neurotropic melanoma, we stained 13 spindle cell melanomas (5 neurotropic melanomas, 5 desmoplastic melanomas, 3 spindle cell melanomas without either desmoplasia of neurotropism) with p75 NGF-R and compared the staining results with S100 and HMB-45, p75 NGF-R is the low affinity nerve growth factor receptor reported to be on the surface of neural-crest-derived cells. Conventional melanoma as well as neurotized nevi, neurofibroma, spindle squamous carcinoma, atypical fibroxanthoma, dermatofibroma and scars were also stained with p75 NGF-R. p75 NGF-R stained all of the desmoplastic and neurotropic melanomas tested. In each of these cases, negative HMB-45 staining of the spindle cells was seen. In many cases the number and intensity of the spindle cells staining with p75 NGF-R was greater than with S100. Neurofibroma, neurotized nevi and focal cells in round cell melanoma also were stained with p75 NGF-R. All the squamous cell carcinomas, atypical fibroxanthomas, dermatofibromas and scars were negative for p75 NGF-R. Based on our results, p75 NGF-R may be useful as an additional confirmatory antibody in a melanoma panel, especially in differentiating desmoplastic and neurotropic melanomas from non-neural-crest-derived spindle cell lesions. We feel it also can be helpful in better identifying margins of excision of these melanomas. p75 NGF-R, like S100 protein, will not differentiate desmoplastic and neurotropic melanomas from other neural-crest-derived lesions. [ABSTRACT FROM AUTHOR]

We report a case of the rare porokeratosis variant porokeratosis ptychotropica (PP). A circumferential perianal plaque and the characteristic histology of multiple cornoid lamellae with underlying dermal amyloid deposition were seen. Amyloid deposition was seen in the biopsied intertriginous area of the plaque only, which, in concordance with other cutaneous amyloid deposition disorders, may suggest a role for friction in the pathogenesis of this histological finding. We review the literature on PP and summarize the poor response seen to treatments. [ABSTRACT FROM AUTHOR]

Background: Cutaneous neuroendocrine neoplasms are typically malignant. Benign cutaneous neuroendocrine tumors are uncommon. Methods: We report the case of a 32-year-old female who presented with a granular mass in the right external auditory canal. Results: Microscopic examination of a shave biopsy revealed a poorly circumscribed neoplasm with glandular differentiation. While cytologic atypia and mitotic activity were not evident, pagetoid spread was observed. Immunohistochemistry was indicative of neuroendocrine origin. Conclusions: This case report of neuroendocrine adenoma indicates that this entity should be entertained in the repertoire of conditions affecting the external ear. [ABSTRACT FROM AUTHOR]

The article presents the case study of the 23 year patient suffering from evaluation of an eruption involving his lower abdomen, thighs and penis. This is a case of extensive neutrophilic infiltration clinically typical fixed drug eruptions (FDEs). The disease represents a rare histopathological variant termed neutrophilic fixed drug eruptions.

The article presents a case study of a 33-year-old Brazilian woman presented for evaluation of an asymptomatic, hairless lesion on her scalp. It mentions computed tomography scan along with histopathology which demonstrated adipocytes extending into the upper reticular dermis. It also states diagnosis of Naevus psiloliparus which is associated with encephalocraniocutaneous lipomatosis, a sporadic neurocutaneous syndrome.

Background Distinguishing banal melanocytic aggregates contiguous with malignant melanoma can be a histological challenge but is essential because of the potential for a spurious Breslow measurement. Objectives Our aim was to ascertain whether the histological distinction between the two relates to differences in the prevalence of mutations in genes significant in melanomagenesis. Methods Mutations in BRAF codon 600, NRAS1 codons 12/13, NRAS2 codons 60/61 and KRAS codons 12/13 were ascertained in 18 cases of primary cutaneous malignant melanoma contiguous with banal melanocytic aggregates using laser capture microdissection. Results Overall, 12 of 18 cases (67%) exhibited a mutation in at least one gene. BRAF V600E appeared to be the most commonly mutated gene in both the melanocytic aggregate (seven of 18, 39%) and the melanoma (four of 18, 22%). Both populations demonstrated a similar BRAF genomic profile in 11 of 18 cases (61%) (two BRAF V600E, nine BRAF-WT), a similar KRAS genomic profile in 14 of 18 cases (78%) (one KRAS G12V, 13 KRAS-WT) and a similar NRAS2 genomic profile in 14 of 18 cases (all WT). Of interest, we noted a relatively high prevalence of KRAS mutations (five of 18, 28%). The frequency of KRAS mutations in the melanocytic aggregate (five of 18, 28%) was second to BRAF V600E, while in melanoma, the frequency was also second to BRAF V600E but equalled that of NRAS2 (1 of 18, 6%). No NRAS1 mutations were observed. BRAF and RAS mutations appeared to be mutually exclusive with only three of 18 cases (17%) demonstrating a mutation in both genes (melanocytic aggregate only). Conclusions Our findings hint towards the interpretation of banal melanocytic aggregates serving as precursor lesions. [ABSTRACT FROM AUTHOR]

We report a unique case of a congenital keratinocytic naevus associated with severe alopecia, onychodysplasia and palmoplantar involvement in a 13-year-old girl. The lesions, consisting of scaly, spinous and verrucous papules and plaques, mainly followed Blaschko’s lines and have remained unchanged since birth. The predominant histopathological picture was that of a column of parakeratosis overlying the eccrine ostia and hair follicles. This is the first case of a systematized keratinocytic naevus characterized by histopathology of eccrine and hair follicle porokeratosis and a widespread bilateral involvement. This may be a distinct entity to be included in the differential diagnosis of linear, hyperkeratotic dermatoses. We suggest its classification as systematized porokeratotic eccrine and hair follicle naevus. [ABSTRACT FROM AUTHOR]

We report a case of cutaneous adenocarcinoma on the pubic region of a 56-year-old male. The exophytic tumor showed solid, ductal, and glandular patterns with decapitation secretion and mucinous carcinoma-like nests. Despite the exophytic nature of the lesion, an invasive growth pattern into the deep dermis and subcutaneous fat was seen. An additional characteristic of this tumor was the presence of Paget's phenomenon. From these findings, we conclude that this tumor is an apocrine adenocarcinoma having an unusual clinical appearance and unique histopathological features which have some similarities to apocrine carcinoma of the breast and some to syringocystadenoma papiliferum and nipple adenomatosis. [ABSTRACT FROM AUTHOR]

The article discusses the case of a 59-year-old man presented with a history of multiple asymptomatic skin lesions that involve the dorsum of his two hands. Histopathological examination shows a rise in the number of dilated blood vessels in the upper and mid dermis along with dermal fibrosis and multiple interstitial angulated multinucleated cells in the mid-dermis. Diagnosis shows that the patient demonstrates Multinucleate cell angiohistiocytoma (MCAH).

A letter to the editor is presented which discusses the case of a 40-year-old female patient with macular amyloidosis.