A 90-year-old woman is referred to dermatology for evaluation of a lesion on her leg that she first noticed four months ago and that has grown quite rapidly. Also, several smaller but otherwise similar lesions have manifested elsewhere on the patient’s body. The lesions, though asymptomatic, concern the patient.

Medical history is significant for colon cancer that was resected four years previously without sequelae. During the course of that disease, the patient received a blood transfusion. Otherwise, she claims to be in “excellent” health and is taking no prescription medications regularly. The patient is of Scottish-Irish descent and has no family history of skin disease.

On examination, the patient looks younger than her stated age but is quite obese. The main lesion in question is a 3-cm firm, exophytic, uniformly purple nodule arising from the surface of the upper medial right leg, with no surrounding erythema or tenderness. No nodes can be palpated in the inguinal area. Three smaller versions of her leg lesion are seen on the dorsum of the right hand and on the opposite leg. All other areas, including the oral mucosa, are free of lesions. No masses, organomegaly, or tenderness is noted during the abdominal exam.

Blood work reveals normal results on a white blood cell count with differential. Excisional biopsy results show, among other things, pleomorphic spindle cells, a high mitotic rate, and multiple slit-like vascular channels. Further testing of the tissue rules out melanoma but shows uniformly positive staining with antibodies to human herpes-virus 8 (HHV 8).

ANSWER
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.

DISCUSSION/TREATMENT
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.