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Background: Recently, a 23-gene signature was developed to produce a melanoma diagnostic score capable of differentiating malignant and benign melanocytic lesions. The primary objective of this study was to independently assess the ability of the gene signature to differentiate melanoma from benign nevi in clinically relevant lesions.Methods: A set of 1400 melanocytic lesions was selected from samples prospectively submitted for gene expression testing at a clinical laboratory. Each sample was tested and subjected to an independent histopathologic evaluation by 3 experienced dermatopathologists. A primary diagnosis (benign or malignant) was assigned to each sample, and diagnostic concordance among the 3 dermatopathologists was required for inclusion in analyses. The sensitivity and specificity of the score in differentiating benign and malignant melanocytic lesions were calculated to assess the association between the score and the pathologic diagnosis.Results: The gene expression signature differentiated benign nevi from malignant melanoma with a sensitivity of 91.5% and a specificity of 92.5%.Conclusions: These results reflect the performance of the gene signature in a diverse array of samples encountered in routine clinical practice. Cancer 2017;123:617-628. © 2016 American Cancer Society. [ABSTRACT FROM AUTHOR]

A perineurioma is a benign peripheral nerve sheath neoplasm thought to be derived from cells of the perineurium, the cellular sheathing of peripheral nerve fascicles. The histological, immunohistochemical (positive for epithelial membrane antigen, collagen type IV, laminin and vimentin but not S-100 protein) and ultrastructural features of a perineurioma form the basis for diagnosis. Two types of perineuriomas are recognized, intraneural and soft tissue (extraneural) forms. Sclerosing perineurioma is considered a variant of the soft tissue perineurioma. In all but one of the reported cases, this subtype presented as a solitary clinical lesion with a predilection for the fingers and palms of young adults. In 2002, Huang and Sung described a 16-year-old boy with one sclerosing perineurioma on each hand. The unusual case presented herein is a 21-year-old woman manifesting more than 30 cutaneous sclerosing perineuriomas on the hands and arms. This case is the most extensive presentation of sclerosing perineuriomas documented to date and extends the clinical presentation spectrum of these lesions. [ABSTRACT FROM AUTHOR]

Myxofibrosarcoma, also known as myxoid malignant fibrous histiocytoma, is increasingly recognized as a distinct malignant neoplasm of fibroblastic origin with variable clinical and histopathologic features. Myxofibrosarcomas are among the most common malignant mesenchymal neoplasms of older adults, and approximately two thirds develop within the dermis or subcutis. Herein, we describe the clinicopathologic features of four cases of myxofibrosarcoma involving the skin. Three of these cases were initially misdiagnosed as benign cutaneous neoplasms, two as myxoid neurofibroma. These cases illustrate the clinicopathologic spectrum encompassed by myxofibrosarcoma in the skin and highlight the diagnostic difficulties it may present. [ABSTRACT FROM AUTHOR]

To examine the effects of chronic ultraviolet light on human epidermal cells, we grafted white human skin onto recombinase activating gene-1 knockout mice. We found previously that the maximal concentration of ultraviolet 8 radiation (290-320 nm) tolerated by human skin xenografts was 500 J per m² when given three times weekly. One hundred and fifty-eight grafted mice were randomized and observed for a median of 10 mo in four groups: (i) no treatment: (ii) one treatment with the chemical carcinogen dimethy--(a)benzanthracene; (iii) ultraviolet B three times weekly; and (iv) a combination of dimethyl-(a)benzanthracene and ultraviolet B. Approximately half of the skin specimens treated with ultraviolet B developed superficial milia and epidermal cysts. Grafts contained up to seven milia lesions between 4 and 8 mo after initiation of treatment, whereas the number of larger epidermal cysts was rarely more than two. Milia and cysts developed in the skin regardless of pigmentation or tanning. Actinic keratoses arose in 9% of grafts treated with ultraviolet B alone and in 19% of grafts treated with the combination of dimethyl- (a)benzanthracene and ultraviolet B. Invasive squamous cell carcinomas developed in 10% of grafts after combined dimethyl-(a)benzanthracene and ultraviolet B treatment and lesions were restricted to skin grafts that did not tan. These findings demonstrate that (i) development of ultraviolet-induced lesions can be experimentally accelerated in human skin, (ii) xenografted recombinase activating gene-1 deficient mice are superior to severe combined immunodeficiency disease mice for chronic ultraviolet B studies, and (iii) benign cystic tumors and squamous cell carcinomas are caused by ultraviolet B. [ABSTRACT FROM AUTHOR]

BACKGROUND. Review of the literature reveals that malignant spiradenomas are rare and may be fatal, and typically manifest as rapid enlargement in long-standing spiradenomas. OBJECTIVE. The present tumor was removed 2 months after it was first noted by the patient. A case of what we believe is the earliest stage of malignant transformation within spiradenoma is reported. METHODS. Case report and literature review. RESULTS. The region with malignant transformation was characterized by nuclear pleomorphism, loss of two cell types, and increased mitotic activity with atypical mitoses. Small infiltrating duct-like structures were seen. The large aggregates and sheets of malignant cells described in long-standing tumors were not seen. CONCLUSION. We ascribe the early detection of this tumor to increased public awareness of the importance in seeking early treatment of skin lesions. Histologic examination of tins stage may eventually outnumber the now more commonly described latter stages. [ABSTRACT FROM AUTHOR]