Abstract

Retiform hemangioendothelioma (RH) is one of a group of borderline vascular neoplasms, intermediate in malignancy between hemangiomas and angiosarcomas. A rare entity, it was first described in 1994 as a form of low grade angiosarcoma. It is now named for its resemblance to the ductular pattern in the rete testis. RH occurs most commonly on the extremities of young adults as a nonspecific firm, slow-growing, solitary nodule or plaque. Management is with complete local excision. Local recurrence is common but metastasis is rare. We describe a case of a 65-year-old woman who attended a dermatologist because of a firm nodule on the left upper back. The clinical differential diagnosis included a cyst, inflammatory acne, scar and dermatofibroma. A punch biopsy was performed. On microscopy an infiltrative arborizing proliferation of elongated vessels, lined by hobnail-like cells with hyperchromatic nuclei, was observed. The stroma was fibrotic and scattered aggregates of lymphocytes were present. On immunohistochemistry, the endothelial cells expressed CD31, ERG, and D2-40. They lacked CD34, HHV-8, cytokeratin AE1/AE3, S100, Mart-1, alpha actin, desmin, synaptophysin, and chromogranin. A diagnosis of RH was rendered, and complete local excision of the lesion was performed. Unusual aspects of this case include the truncal location of the lesion and the ‘older than average’ age of the patient. We report it to contribute to the existing demographic and clinical spectrum of a rare entity. Moreover, by highlighting the histopathology and immunophenotype of RH we hope to hone diagnostic accuracy and promote optimal management.

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