Abstract:

Cutaneous Kaposi sarcoma (KS) is a vascular neoplasm with a broad spectrumclinicopathology. An epithelioid morphology, a rare recent variant of KS, with many variants of KS that may mimic other vascular neoplasms poses a diagnostic challenge. We report on a 75-year-old Saudi man HIV- negative who had been diagnosed with classical KS on the right foot 8 years before the present episode. Histopathological findings of the new lesion included areas showing epithelioid cells with moderate pleomorphism, growing in solid sheets. The epithelioid cells show nuclear enlargement and hyperchromasia mimicking angiosarcoma. Immunohistochemistry shows a strong diffuse nuclear staining pattern for HHV-8 latent nuclear antigen-1 (LNA-1) in the epithelioid as well as the classical spindle cells. A diagnosis of epithelioid Kaposi sarcoma is made, which should be included within the known histological variants of KS. Prior to this case, the epithelioid variant of Kaposi sarcoma has been reported only three times in the literature. Since this variant shares similar clinical and histological features with angiosarcoma, integration of clinical findings and context, histopathologic features and immunohistochemical results is critical in obtaining the correct diagnosis and treatment.

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