The correct answer is Kaposi’s sarcoma (choice “c”), known since 1995 to be caused by HHV 8, presenting with the histopathologic features described above. See below for more discussion of this decidedly unusual diagnosis.
Given the patient’s history, metastatic colon cancer (choice “a”) was a distinct possibility but was ruled out by the biopsy. Angiosarcoma (choice “b”), another malignancy of vascular origin, seldom presents in “lesional” form; it is far more likely to present as broad-based plaques or patches of red, multiple papules interspersed with focal erosions, typically on the head, neck, or chest. It would, of course, be HHV 8–negative.
Hemangioma (choice “d”) is a benign papule or nodule composed of multiple dilated capillaries adhered in a lesional morphology. With a totally benign histological picture and cherry-red color, these are easy to distinguish from more worrisome items in the differential.
Kaposi’s sarcoma (KS) in HIV-positive or otherwise immunosuppressed patients is relatively common, but it is not so in immunocompetent patients. The latter is termed “classic” or sometimes “European” KS, since it is far more common in Europe (particularly the eastern and southern regions) and especially in males native to the Mediterranean areas or of Ashkenazi Jewish descent. Our patient fit none of these patterns and yet definitely had KS.
As of this writing, the patient is awaiting evaluation and treatment by oncology. Almost certainly, part of her work-up will be to rule out any form of immune suppression. And since KS can progress to visceral involvement, her staging work-up will involve appropriate imaging as well.
Treatment choices include intralesional injection of isolated lesions with vinblastine, excision of individual lesions, or systemic chemotherapy with drugs such as doxorubicin, vinblastine, and others as single agents or in combination.