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The article focuses on the diagnosis of a painful, nonhealing, violaceous plaque on the right breast of a 42-year-old woman. The differential diagnosis includes diffuse dermal angiomatosis, dermatofibroma, dermatofibrosarcoma protuberans, angiosarcoma, and Kaposi sarcoma. The authors discuss the clinical and histopathological characteristics of each condition, emphasizing the features that help differentiate them, and provide images to aid in the recognition of the dermatopathological entities.

Dear Editor, A 41-year-old woman with a history of asthma was admitted with acute onset of a diffuse painful nonpruritic rash with cephalocaudal progression. Complete resolution of the facial lesions following high-dose corticosteroid therapy (d) gl Despite IV acyclovir, the patient continued to clinically deteriorate. Fibrin deposition and neutrophils were noted within the vessel walls consistent with leukocytoclastic vasculitis (b, Hematoxylin-eosin stain ×40) gl Upon review of the literature and a previously reported case of false-positive HSV DFA in a patient with severe eosinophilia, it was decided to stop IV acyclovir and start high-dose corticosteroids for a working diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA). [Extracted from the article]

Approximately 25% of the inflammatory infiltrate showed CD23 SP + sp immunostaining, consistent with the patient's underlying diagnosis of CLL. HZ granulomatous dermatitis in this case should be differentiated from acute HZ infection. Although acute HZ may show a lymphoplasmacytic infiltrate, multinucleated giant cells are more characteristic of a late granulomatous reaction, which favors a diagnosis of HZ granulomatous dermatitis.[1] However, it should be noted that acute HZ shares some histologic features with HZ granulomatous dermatitis and that granulomatous changes can appear in acute HZ presentations within 6 weeks of onset.[1]. [Extracted from the article]

Histologic differentiation of melanoma in situ (MIS) from solar keratosis on chronically sun‐damaged skin is challenging. The first‐line immunostain is usually MART‐1/Melan‐A, which can exaggerate the epidermal melanocytes, causing a diagnostic pitfall for MIS. By comparing MART‐1 and SOX10 immunostaining, we scored the percentage of epidermal melanocytes per 2‐mm diameter fields in pigmented actinic keratosis (n = 16), lichenoid keratosis (n = 7), junctional melanocytic nevus (n = 6), keratosis with atypical melanocytic proliferation (n = 17) and MIS (n = 10). These cases represented an older population (68 years median age) and the head and neck (50%) was the most common anatomic site. MART‐1 score was significantly higher than SOX10 (P value <.05) in solar keratoses, but showed no difference in detecting melanocytic proliferations, demonstrating their equal detection rate of melanocytes. The sensitivity of both MART‐1 and SOX10 was 100%, while their specificities were 17% and 96%, respectively. These results show that SOX10 is more specific than MART‐1 in distinguishing epidermal melanocytes on sun‐damaged skin by avoiding overdiagnosis of melanoma. [ABSTRACT FROM AUTHOR]

Several types of cutaneous reactions have been reported to arise at the site of herpes zoster ( HZ) infection weeks to years after the acute disease. Among these, granulomatous reactions are the most frequently reported. In this study, we describe the spectrum of histopathologic findings of HZ granulomatous reactions observed in 26 patients with cutaneous lesions confined to the area of previous HZ eruption and compare them with biopsy specimens taken from 25 patients with acute HZ. All patients with persistent reactions from whom history was available presented within 12 weeks of the onset of the acute eruption. The most frequent findings were interstitial granulomatous dermatitis with lymphocytes, histiocytes and multinucleated giant cells displaying elastophagocytosis and a perineural, perivascular and perieccrine mononuclear inflammatory infiltrate rich in lymphocytes and plasma cells. Less common features included intra-arrector and peri-arrector pili granulomas, follicular dilatation and hyperkeratosis, and vasculitis. Specimens from patients with acute HZ were found to have small numbers of perineural plasma cells and most had subtle granulomatous inflammation, in patterns similar to the group with late granulomatous reactions. Our findings suggest that granulomatous reactions to varicella zoster virus represent a persistent evolving inflammatory reaction after acute infection. [ABSTRACT FROM AUTHOR]

Although initial review of system and workup were negative, the patient developed Gottron's papules and shawl sign with subjective muscle weakness and shortness of breath 6 months later. Dear Editor, Dermatomyositis (DM) is an idiopathic inflammatory myopathy with distinctive cutaneous manifestations. Unlike the previously reported amyopathic dermatomyositis case,5 our cases suggested that deck-chair sign could be seen in both classic and amyopathic dermatomyositis, although it seems to first develop during a clinically amyopathic state. [Extracted from the article]

PEComas are mesenchymal neoplasms composed of perivascular epithelioid cells (PEC) and include a spectrum of tumors. PEComas and malignant melanoma share common morphological, immunohistochemical, and ultrastructural features, such as epithelioid cell morphology and melanocytic immunophenotype. Melanocytic markers commonly expressed in PEC tumors include HMB-45, Melan-A/MART-1, tyrosinase, microphthalmia transcription factor (MITF), and occasionally, S100. Given this morphological and immunophenotypical overlap, the differential diagnosis between a PEComa and malignant melanoma can represent a challenge. Additional diagnostic difficulty is the differentiation of melanoma and PEComa from clear cell sarcoma that is indistinguishable from melanoma based on the immunohistochemical profile. Recent studies have shown that MUM-1, a known lymphocyte marker shows positive immunostaining in nevi and melanomas, its expression in PEComas and clear cell sarcoma, however, has not been previously addressed. In this study, the authors analyzed MUM-1 expression using immunohistochemistry in PEComas (n = 8), the PEComa family members, angiomyolipomas (n = 13), and clear cell sarcomas (n = 11) and compared the staining pattern with malignant melanomas (n = 25), both primary (n = 14) and metastatic (n = 11). It was found that 92.3% of primary melanomas and 81.3% of metastatic melanomas were MUM-1 positive. In contrast, MUM-1 was only weakly positive in only 25% of PEComas and negative in all angiomyolipomas. MUM-1 expression was noted in 72.7% of clear cell sarcomas. The study demonstrated differential MUM-1 expression between PEComas and other true melanocytic tumors and suggested that the addition of MUM-1 to the usual panel of melanocyte markers could be a helpful adjunctive study to aid in the differential diagnosis between these entities. [ABSTRACT FROM PUBLISHER]

The prognosis of patients with stage IV cutaneous T-cell lymphoma (CTCL) is grim and therapeutic options are limited. Treatment of advanced-stage CTCL is aimed at suppressing the dominant T-cell clone, which is typically present in the skin, peripheral blood, and lymph nodes. We detected the expansion of 1 T-cell clone expressing the T-cell receptor V314 in the peripheral blood of a patient with stage IVA CTCL. Before initiation of combination therapy with pho-topheresis and low-dose interferon 3, the dominant T-cell clone represented 84% of the total T-cell population. After successful therapy, this clone showed a dramatic decrease to 6% of the T-cell population after 6 months of treatment. This reduction in the percentage of the malignant T-cell population in response to therapy was paralleled by clinical skin improvement from initial generalized erythroderma to undetectable skin disease. This case demonstrates that response to combination treatment with photopheresis and low-dose interferon 3 in patients with advanced CTCL may be accurately and quantitatively followed up by monitoring the percentage of the malignant T-cell clone (when identifiable) within the total circulating T-cell population by flow cytometry. [ABSTRACT FROM AUTHOR]

Nodular cystic fat necrosis is a rare, benign form of encapsulated fat necrosis with distinct histology, characterized by cystic fat necrosis with lipomembranous changes and, in later stages, calcification. We report the case of a 7-year-old child with juvenile dermatomyositis who presented with three asymptomatic, firm, mobile nodules on the arms and neck. Histology was consistent with nodular cystic fat necrosis with prominent calcification. This is an unusual presentation of this entity because it has never been previously reported in association with juvenile dermatomyositis. [ABSTRACT FROM AUTHOR]

The article focuses on the study of F. van Maldegem and colleagues on the difference of primary cutaneous marginal zone B-cell lymphoma (PCMZL) to other extranodal MZL. It states that the report suggests that PCMZL lacks CXCR3 and demonstrates class-switched immunoglobulin and occasional dual isotypes. It cites the differences between PCMZL and mucosa-associated lymphoid tissue (MALT) lymphomas and concludes that PCMZL is part of the broad group of extranodal MZL.

The article discusses the role of T-cells in primary cutaneous CD4+ small/medium-sized pleomorphic T-cell lymphomas (PCSMTCL). It cites that PCSMTCL commonly presents as a solitary plaque or tumor on the head, neck, or extremities. It references the article of Rodriguez Pinilla and collegues showing that the atypical CD4+ T-cells in PCSMTCL express follicular helper T-cells markers. These markers include programmed cell death-1 (PD-1), CXCL13, and BCl-6 that are associated with B-cells.