Cutaneous Kaposi sarcoma and its mimics

Abstract Kaposi sarcoma (KS) is a human herpes virus-8 (HHV8) – associated vasoformative lesion affecting the skin, mucosae, and viscera. Conventional cutaneous KS manifests with patch, plaque, or nodular lesions, with each subtype exhibiting distinctive histomorphology. Recent decades, however, have revealed a broader histological spectrum of KS in the skin. Recognition of the wide range of microscopic variants of KS and their individual mimics is essential for correct diagnosis. This is enhanced by careful clinico-pathological correlation and the utilisation of appropriate ancillary investigations. The demonstration of nuclear staining for HHV8 latency associated nuclear antigen by immunohistochemistry enables confirmation of a given KS variant. Conversely, negative immunoreactivity for HHV8 is a unifying feature among the numerous dermatoses and/or neoplasms that constitute the differential diagnosis of a given KS subtype.