Fine-needle aspiration cytology of disseminated Kaposi sarcoma of the bone in an AIDS patient.

BACKGROUND: Kaposi sarcoma (KS) is a vascular neoplasm associated with human herpesvirus 8 (HHV-8). Skin and mucous membranes are the most common sites, but other organs may be involved. Skeletal KS is rare and occurs either by direct spread of mucocutaneous lesions or through dissemination. Patients present with bone pain and lytic lesions for which they may undergo fine-needle aspiration (FNA). While there are about 70 published case reports of skeletal KS, there is limited literature specifically describing its cytomorphology. Our literature search yielded only a single prior reported case of FNA biopsy of skeletal KS in a Nigerian AIDS patient. CASE: We present a case of disseminated KS of the axial skeleton in a 45-year-old African-American man with AIDS which was diagnosed on FNA cytologic examination. The patient presented with multiple lytic lesions in the axial skeleton. The aspirate, core-needle biopsy and touch imprint cytology of a bone lesion demonstrated clusters of spindle and epithelioid cells in radial and streaming arrangement with indistinct intercytoplasmic borders, elongated nuclei, fine chromatin and inconspicuous nucleoli. Immunohistochemical studies revealed positivity for HHV-8 and vascular markers. The cytomorphologic and ancillary features of the case are presented and discussed.