Track: Case Reports

Abstract:

We present a diagnostically challenging case of cutaneous reactive angiomatosis with overlapping features of reactive angioendotheliomatosis (RAE), intravascular histiocytosis (IVH), and intralymphatic histiocytosis (ILH) arising in previously irradiated skin of a patient with metastatic melanoma. This case highlights key histopathologic and immunophenotypic findings relevant to distinguishing reactive vascular lesions from angiosarcoma or metastatic melanoma. A 57-year-old woman with metastatic melanoma developed violaceous papules and macules localized to prior radiation fields approximately ten months after completion of therapy. A punch biopsy was performed and evaluated with H&E and an immunohistochemical panel including ERG, D2-40, CD68, and melanocytic markers. Histopathology revealed a poorly circumscribed proliferation of thin-walled dermal vessels lined by bland, plump endothelial cells, with focal intravascular histiocytoid cells. ERG highlighted endothelial cells; D2-40 confirmed lymphatic vessel involvement; CD68 marked intravascular histiocytes. Melanocytic markers were negative. These findings supported a benign reactive vascular proliferation with overlapping features of RAE, IVH, and ILH. The lesions remained stable with topical corticosteroids despite systemic disease progression. This case reinforces the importance of recognizing post-radiation reactive vascular proliferations, particularly in patients with a history of melanoma, where recurrence or angiosarcoma is a concern. Integration of clinical context, histomorphology, and immunohistochemistry is essential. Our findings support a unifying spectrum of cutaneous reactive angiomatoses with variable lymphatic and histiocytic involvement.

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Kinan Maurice Hayani