PRAME-negativity in sclerosing nevi with pseudomelanomatous features supports classification as an indolent lesion.

Background: Some dysplastic nevi, termed sclerosing nevi with pseudomelanomatous features, may have florid fibroplasia associated with features that cause melanoma to be a prominent consideration in the differential diagnosis. PRAME (PReferentially expressed Antigen in MElanoma) immunohistochemistry (IHC) has been shown to be a useful marker in the distinction of melanoma and nevus. PRAME expression in such sclerosing nevi with pseudomelanomatous features has not been evaluated to our knowledge.

Cognitive bias in pathology, as exemplified in dermatopathology.

Cognitive bias refers to human thinking patterns, as well as pitfalls, that are reproducible. Importantly, cognitive bias is not intentionally discriminatory and is necessary to properly interpret the world around us, including microscopic slides. Thus, it is a useful exercise to examine cognitive bias in pathology, as exemplified in dermatopathology.

Acute Epstein-Barr virus infection resembling cutaneous T-cell lymphoma.

Primary, acute Epstein-Barr virus (EBV) infection is associated with a variety of cutaneous eruptions, including the viral exanthem of infectious mononucleosis and erythema multiforme. Latent, chronic EBV infection can rarely result in development of lymphoproliferative disorders with cutaneous manifestations; however, these disorders do not arise from primary infection. In this report, we present a case of primary, acute EBV infection presenting with histopathologic features closely mimicking aggressive cytotoxic cutaneous T-cell lymphoma.

Cutaneous Involvement in Plasma Cell Myeloma.

Objectives: Plasma cell myeloma (PCM) involving skin is rare and occurs in 1% to 4% of patients with PCM. We evaluated the clinicopathologic features, cytogenetic findings and clinical follow-up in a series of PCM cases with cutaneous involvement.

Methods: Cases of PCM with cutaneous involvement were retrospectively reviewed with clinical data.

More than keratitis, ichthyosis, and deafness: Multisystem effects of lethal GJB2 mutations.

Background: Infant death in keratitis-ichthyosis-deafness (KID) syndrome is recognized; its association with specific genotypes and pathophysiology is inadequately understood.

Objective: We sought to discover characteristics that account for poor outcomes in lethal KID syndrome.

Methods: We collected 4 new cases and 9 previously reported, genotyped cases of lethal KID syndrome.

Bullous disorders associated with anti-PD-1 and anti-PD-L1 therapy: A retrospective analysis evaluating the clinical and histopathologic features, frequency, and impact on cancer therapy.

Background: Bullous disorders associated with anti-programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) therapy are increasingly reported and may pose distinct therapeutic challenges. Their frequency and impact on cancer therapy are not well established.

Objective: To evaluate the clinical and histopathologic findings, frequency, and impact on cancer therapy of bullous eruptions due to anti-PD-1/PD-L1 therapy.

Squamous proliferations on the legs of women: Qualitative examination of histopathology, TP53 sequencing, and implications for diagnosis in a series of 30 cases.

Background: Women with multiple squamous cell carcinomas (SCCs) of the legs have a striking clinical phenotype. Numerous tumors can develop in a short period of time.

Objective: Because histopathologic findings can vary in women with multiple SCC lesions, from keratoacanthoma-like to well-differentiated SCC, we hypothesized that TP53 variants might shed light on the appropriate classification.

Congenital nevi versus metastatic melanoma in a newborn to a mother with malignant melanoma - diagnosis supported by sex chromosome analysis and Imaging Mass Spectrometry.

A 37-year-old pregnant woman presented with a 2-cm irregular reddish nodule on her left upper arm during pregnancy. A biopsy from the lesion showed a 2.2-mm thick malignant melanoma with intravascular invasion, 25 mitosis/mm(2) and no ulceration.

Cytokeratin 20 expression in basaloid follicular hamartoma and infundibulocystic basal cell carcinoma.

Background: Tumors with similar or identical histopathologic features have been termed basaloid follicular hamartoma (BFH) or infundibulocystic basal cell carcinoma (BCC). BCC typically lacks immunoreactivity with cytokeratin 20 (CK20) and pleckstrin homology-like domain, family A, member 1 protein (PHLDA1).

Aim: A series of BFH and infundibulocystic BCC were investigated to determine the pattern of CK20 and PHLDA1 labeling in these lesions.

p40 is a more specific marker than p63 for cutaneous poorly differentiated squamous cell carcinoma.

Background: Poorly differentiated squamous cell carcinoma (SCC) of the skin may pose a diagnostic challenge for pathologists. p40 is a recently introduced antibody that recognizes specific p63 protein isoforms and has shown superior results labeling non-cutaneous SCC. We hypothesize that p40 may improve diagnostic accuracy of poorly differentiated SCC.

An incompletely penetrant novel mutation in COL7A1 causes epidermolysis bullosa pruriginosa and dominant dystrophic epidermolysis bullosa phenotypes in an extended kindred.

Epidermolysis bullosa pruriginosa (EBP) is a rare subtype of dystrophic epidermolysis bullosa (DEB) characterized by intense pruritus, nodular or lichenoid lesions, and violaceous linear scarring, most prominently on the extensor extremities. Remarkably, identical mutations in COL7A1, which encodes an anchoring fibril protein present at the dermal-epidermal junction, can cause both DEB and EBP with either autosomal dominant or recessive inheritance. We present one family with both dystrophic and pruriginosa phenotypes of epidermolysis bullosa.

The melanoma 'epidemic': lessons from prostate cancer.

The rise in malignant melanoma incidence has been termed "epidemic". Closer scrutiny of epidemiologic data suggests overdiagnosis as the true cause of the dramatic rise in melanoma incidence. In epidemiologic terms, "overdiagnosis" describes lesions that are histologically malignant but biologically benign.

Quantitative comparison of MiTF, Melan-A, HMB-45 and Mel-5 in solar lentigines and melanoma in situ.

Background: It is often challenging to reliably assess the number of lesional melanocytes in intraepidermal melanocytic proliferations involving sun-damaged skin. Therefore, dermatopathologists routinely use immunostains to help differentiate melanocytes from surrounding keratinocytes.

Methods: Forty-three cases of solar lentigo or melanoma in situ (of the lentigo maligna type) were retrospectively chosen (20 melanomas in situ and 23 solar lentigo).

The melanoma 'epidemic', a dermatopathologist's perspective.

Over the past several decades, the rise in melanoma incidence has been termed "epidemic." However, detailed analysis of mortality data suggests that the true incidence of melanoma has not increased dramatically. Dermatopathologists, who hold a key position in the diagnosis of melanoma, should have unique insight into this quandary.

"Clark/dysplastic" nevi with florid fibroplasia associated with pseudomelanomatous features.

Background: Melanocytic nevi may exhibit histologic features in common with cutaneous melanoma, creating diagnostic difficulties.

Objective: We sought to assess the clinical behavior of melanocytic nevi with pseudomelanomatous features in association with dermal fibrosis.

Methods: Forty-two melanocytic nevi with pronounced fibrosis and associated pseudomelanomatous changes were collected and studied clinically and histologically.

Promontory sign--present in patch and plaque stage of angiosarcoma!

Kaposi sarcoma is characterized by a proliferation of irregular jagged vascular channels, which partly surround preexisting blood vessels in some areas. This characteristic appearance of a small vessel protruding into an abnormal vascular space has been termed "promontory sign". Cutaneous angiosarcoma (AS) is a malignant vascular neoplasm comprised of a meshwork of anastomosing irregular dilated vessels between collagen bundles and around skin appendages, lined by atypical endothelial cells.

Melanocytic nevi with features of Spitz nevi and Clark's/dysplastic nevi ("Spark's" nevi).

Background: Nevi with cytologic characteristics of Spitz nevus and architectural features of Clark's/dysplastic nevus are not well recognized in the literature.

Methods: Twenty-seven nevi with characteristics of Spitz nevus and Clark's/dysplastic nevus are reviewed.

Results: The patients' mean age was 33 years, and 17/27(63%) patients were female.

Mohs micrographic surgery histopathology concordance.

Background: The low recurrence rate and tissue-sparing benefit associated with Mohs micrographic surgery (MMS) requires accurate interpretation of frozen sections by the MMS surgeon.

Objective: We sought to assess concordance between dermatopathologists and MMS surgeons when reporting cutaneous malignancy in the MMS setting.

Methods: This study is a retrospective analysis of 1156 slides submitted during 10 years as part of a pre-existing randomized, blinded, quality assurance protocol.