Journal of Cutaneous Pathology最新文献

Background: Preferentially expressed antigen in melanoma (PRAME) has been extensively studied in cutaneous melanocytic tumors and has proven valuable as a diagnostic adjunct in routine dermatopathology practice. However, its expression in cutaneous vascular neoplasms, particularly angiosarcomas (AS), remains largely unexplored.

Methods: To further explore PRAME expression in cutaneous AS, 18 cases of post-irradiation and 13 cases of primary cutaneous AS were evaluated for PRAME. For comparison, sections from 11 deep soft tissue/visceral AS, 10 Kaposi sarcomas, 8 microvenular hemangiomas, 7 infantile hemangiomas, 8 atypical vascular lesions, 6 epithelioid hemangioendotheliomas, 6 pyogenic granulomas, 6 papillary endothelial hyperplasias, 6 epithelioid hemangiomas, 3 capillovenous malformations, 3 hobnail hemangiomas, 2 spindle cell hemangiomas, 2 pseudomyogenic hemangioendotheliomas, and 2 composite hemangioendotheliomas were also retrieved.

Results: Overall, 22 of 31 (70.9%; 12 post-irradiation and 10 primary) cutaneous AS were positive for PRAME. In contrast, only 1 of 11 (9.1%) deep soft tissue/visceral AS showed diffuse and strong PRAME nuclear staining. All other tumor types were negative for PRAME, except for 5 of 7 (71.4%) infantile hemangiomas, which demonstrated rare (<5%; four cases) and 1+ (5-25%; one case) nuclear staining.

Conclusions: In this study, we have demonstrated frequent nuclear PRAME expression in cutaneous AS. PRAME immunohistochemistry may serve as a valuable additional marker in selected clinical settings.

Diseases in which cutaneous plasma cell infiltrates predominate are rare and usually of unknown etiology, including those that transition from benign to malignant, such as cutaneous plasmacytosis, multicentric Castleman disease, and extramedullary plasmacytoma. These diseases may present as purplish, reddish-brown cutaneous plaques or nodules. Here, we report an exceptional case of lichen planus (LP) in which the patient had classic histopathological features, but the infiltrating inflammatory cells were plasma cells with restricted light chain expression. The patient presented with severe rashes, including purplish-red plaques and nodules, erythema, and erosions in the palmoplantar area, verrucous hyperplasia of the oral mucosa, and anonychia of the toes. These findings suggest a possible role of plasma cells with restricted light chain expression in the LP. Clinicians should closely follow patients for changes in their rash, perform repeat biopsies if necessary, and regularly conduct multisystemic evaluations.

Rarely, Rosai-Dorfman disease (RDD) manifests exclusively in the skin, typically as nodules on the trunk and extremities. Recognition of characteristic histopathologic features enables diagnosis of RDD. A 55-year-old female presented with a 7-year history of cutaneous nodules involving the trunk and extremities. A prior skin biopsy specimen at a different institution had demonstrated a dense dermal lymphohistiocytic infiltrate with histiocytes containing GMS+ forms, favored to represent cryptococcal organisms, with a differential diagnosis including other infections with parasitized histiocytes. Despite antibiotic therapy, lesions persisted. After a presentation to our institution, a biopsy specimen showed a diffuse infiltrate, including histiocytes with voluminous pale cytoplasm with focal emperipolesis of inflammatory cells and S100 immunohistochemical positivity. Clinical and radiologic examinations did not identify significant extracutaneous involvement. A genetic study performed on the biopsy specimen identified a K57Q mutation of MAP2K1. The presence of this mutation correlated with prior reports of MAP2K1 mutation in classic RDD, thereby supporting our histopathologic diagnosis of RDD over an infectious process and further illuminating options for targeted therapies. At 3-year follow-up, the patient has been managed with a course of systemic corticosteroids and excision of bothersome lesions. Consideration of systemic therapy is ongoing.

Background: The subcellular distribution of CD30 on mast cells and the presence of eosinophils in cutaneous mastocytosis require further investigation, especially as the cell surface expression of CD30 is critical for the therapeutic response of systemic mastocytosis to brentuximab vedotin.

Objective: Investigation of 147 biopsy specimens from 143 patients with cutaneous mastocytosis for mast cell density and distribution, frequency of CD30 expression, CD30 staining patterns, and presence and distribution of eosinophils. Correlation with clinical patterns.

Methods: Retrospective multicenter immunohistochemical study of CD30 expression, eosinophils and basic clinical data in cutaneous mastocytosis.

Results: CD30 expression was found in all samples (cut-off: ≥1%), whereby the staining was predominantly cytoplasmic in 99% of the samples. Additional membrane staining was detected in 62% of the samples. Surface expression of CD30 was more common in biopsy specimens with a high mast cell burden and in biopsy specimens with a higher CD30 expression rate. Eosinophils were admixed in 58% of the samples. Females and older patients showed a trend of a lower mast cell burden.

Limitations: Retrospective study on formalin-fixed and paraffin-embedded tissue without functional analysis.

Conclusion: Most cases of cutaneous mastocytosis show cell surface expression of CD30 expression and is, therefore, in principle, accessible for therapy with antibodies against CD30, provided the overall situation of the patient warrants.

Background: Primary cutaneous marginal zone lymphoma (PCMZL) and primary cutaneous CD4+ small/medium T-cell lymphoproliferative disease (CD4+ TLPD) are two distinct entities with excellent prognosis; however, they show profound clinical and histopathological similarities, leading to differential diagnostic uncertainty.

Aims: Our aim was to review and reanalyze cases of primary cutaneous lymphoproliferations diagnosed at Semmelweis University, featuring characteristics of PCMZL and CD4+ TLPD.

Materials and methods: Cutaneous lymphoma biopsy specimens between 2018 and 2022 were collected and re-evaluated. Medical history, clinical picture, imaging, and laboratory findings were collected. Immunohistochemical staining for CD20, CD3, BCL6, CD10, PD1, CD3, CD4, CD8, and PCR tests for IGH, IGK, TCRB, and TCRG were repeated in selected cases.

Results: Among 55 cases diagnosed as PCMZL (16) or CD4+ TLPD (39), 3 patients had been diagnosed with both LPDs at different time points of their disease course. Four additional patients were identified with single lesions featuring overlapping histopathological characteristics of both LPDs and both monoclonal IGH and TCR rearrangements. All patients are currently in complete remission with local treatment.

Conclusion: We propose that besides the overlapping histopathological, molecular, and clinical features, the subsequent appearance of PCMZL and CD4+ TLPD in a short timeframe in the same patients may suggest a common pathogenic background.

Background: Histopathologic criteria for diagnosis of cutaneous mastocytosis include 20 mast cells per high-power field or clusters of 15 mast cells. We aimed to determine the specificity of these criteria for cutaneous mastocytosis in comparison with inflammatory disorders of mast cell activation.

Methods: Twenty-six cases of spongiotic dermatitis or urticaria were identified from 2021 to 2022. Recuts were stained with mast cell tryptase and slides were reviewed for the presence of 20 mast cells per high-power field and for clusters of 15 mast cells. In addition, seven cases of mastocytosis were reviewed for the same criteria.

Results: Twelve of 26 cases (46.1%) of spongiotic dermatitis/urticaria had at least 20 mast cells per high-power field. Three of 26 cases (11.5%) of spongiotic dermatitis/urticaria had a cluster of 15 mast cells. Six of seven cases (85.7%) of mastocytosis had at least 20 mast cells per high-power field; four of seven cases (57.1%) of mastocytosis had a cluster of 15 mast cells.

Conclusions: In our study, the finding of 20 mast cells per high-power field was nonspecific as a single criterion for cutaneous mastocytosis. The finding of clusters of 15 mast cells was more specific but not sensitive.

The terms "onychofibroblast" (nail-specific fibroblast) and onychodermis (nail-specific dermis) were first introduced in 2006 and 2012, respectively, based on distinctive histologic and immunohistochemical features from the dermis of the surrounding skin and have been demonstrated in multiple studies. Recently, based on molecular research, the definition of onychodermis containing onychofibroblasts has been expanded to encompass the area located between the nail matrix and bed epithelium and periosteum. Single-cell RNA sequencing and in situ hybridization demonstrated that onychofibroblasts within the onychodermis express the genes including RSPO4, MSX1, WIF-1, and BMP5, which are implicated in nail formation and/or in disorders with nail phenotype. A mutation in RSPO4, a component of the Wnt signaling pathway, causes anonychia congenita. Nail matrix onychodermis and nail bed onychodermis share many similar characteristics which differ from the surrounding normal dermis of the skin. Comparative spatial transcriptomic and single-cell analyses of human nail units and hair follicles suggest that onychodermis is the counterpart of follicular dermal papilla, which plays a key role in hair follicle growth and morphogenesis. Onychomatricoma, as a nail-specific tumor, has been demonstrated to be a mesenchymal tumor that originates from onychofibroblasts and is associated with the upregulation of Wnt signaling. Collectively, the onychodermis and onychofibroblasts play crucial roles in nail development and these specialized nail mesenchymal elements are key components in the pathogenesis of onychomatricoma. The concept of onychodermis containing onychofibroblasts is very important for nail biology and pathology.