Clinical Challenge: Purplish Bumps on the Forearm

Kaposi sarcoma (KS) is a rare tumor of lymphatic and vascular endothelial cell origin that is linked with infection of human herpesvirus 8 (HHV-8, also known as KS-associated herpesvirus or KSHV), which has been shown to have both sexual and...

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Kaposi sarcoma (KS) is a rare tumor of lymphatic and vascular endothelial cell origin that is linked with infection of human herpesvirus 8 (HHV-8, also known as KS-associated herpesvirus or KSHV), which has been shown to have both sexual and nonsexual modes of transmission.

KS is classified in four forms: classic KS (typically affecting older Caucasian males with Mediterranean or Jewish backgrounds), endemic African KS (affecting­ children and adults in Central Africa), iatrogenic KS (immunocompromised patients), and finally, the present diagnosis, HIV-associated KS or AIDS-KS (affecting those with HIV infection, particularly homosexuals).

Today, KS is the second most common tumor in homosexual HIV-infected patients. It has also become the most common neoplasm of HIV-stricken sub-saharan Africa, where HHV-8 is endemic.

AIDS-KS is an aggressive form of KS, and can disseminate to the lungs, gastrointestinal (GI) tract, lymph nodes and spleen. Early lesions of AIDS-KS appear as small, oval violaceous macules and papules favoring the face, trunk and oral mucosa in contrast to other variants of KS. Without treatment these lesions can quickly evolve into large debilitating plaques and nodules.

Diagnosis

Early stage (or ‘patch stage’) cutaneous KS tumors can look like purpura, angiomas, dermatofibromas, pyogenic granuloma, arteriovenous malformations, and angiosarcoma. Skin biopsy may be necessary to make the diagnosis, along with staining for HHV-8 protein in the tumor cells.

Lesions can be pink, purple or brown and vary in size. The plaque stage involves larger lesions with edema and lymph node involvement. Eventually, lesions can evolve into ulcerating tumors in the nodular stage.

Early on, in more than a third of AIDS-KS cases, there are extracutaneous manifestations of the disease that can arise in the oral cavity and GI tract (presenting as abdominal pain, weight loss, diarrhea, vomiting or bleeding).

The most life-threatening form of KS is pulmonary KS (presenting as shortness of breath or cough) that may be revealed by abnormal findings on chest x-ray.

In HIV patients, KS is considered an AIDS defining illness.

Treatment and Prognosis

Rate of tumor growth, severity of symptoms and concurrent disease related to AIDS are factors considered in treating AIDS-KS.

For patients with progressive KS involving extracutaneous systemic manifestations, highly active antiretroviral therapy (HAART) is essential for suppressing viral replication. KS lesions begin to shrink and may disappear altogether in response.

A dangerous complication of this treatment may be immune reconstitution and inflammatory syndrome (IRIS). Local therapy such as intralesional vinblastine, cryotherapy, excisional surgery, aliretinoid gel, and radiotherapy may be feasible options for control of skin lesions in addition to HAART.

For patients not responding to HAART or who have very severe symptoms, systemic chemotherapy such as liposomal anthracyclines may be necessary.

Neil D’Souza is a medical student at Baylor College of Medicine.

Adam Rees, MD, a graduate of the David Geffen School of Medicine at UCLA, practices dermatology in Los Angeles.

References

1. Wood C, Harrington W. Cell research 15.11 (2005): 947-952.
2. Goldsmith L et al. Fitzpatrick’s Dermatology in General Medicine, Eighth Edition. The McGraw-Hill Companies, Inc., 2012. Access Medicine. Web. 10 May 2014.
3. Lena J et al. PLoS one 6.4 (2011): e18397.
4. Martellotta F et al. Current HIV research 7.6 (2009): 634-638.