Diagnosis Lymphedemalike Kaposi’s sarcoma
Kaposi’s sarcoma (KS) is caused by human herpesvirus 8 (HHV-8). For more than 100 years, this condition with an infectious etiology was known as a neoplasm most common in elderly and middle-aged Jewish men or men from the area surrounding the Mediterranean. For reasons not understood, in some hosts, HHV-8 causes vascular proliferation and occasionally lymphatic proliferation and pathologic alteration.
All four main types of KS are more common in men than women. Classic KS develops without any overt state of immunocompromise, except the waning immunity of old age. Only the skin is affected, usually on the lower legs and feet. I have seen classic KS in Hispanics.
Endemic, or African, KS occurs in sub-Saharan Africa, where it represents up to 10% of all tumors and develops more quickly than classic KS. Unlike classic KS, endemic KS affects women and children of all ages. In Africa, in children aged 2-3 years, the disease is often associated with generalized involvement of lymph nodes and resembles lymphoma.
AIDS-related KS, the most commonly occurring type in the Western world, is an AIDS-defining illness. The incidence of AIDS-related KS increases as the CD4 count drops below 200/µL and abates as the CD4 count rises above 200. It can manifest in the lungs, skin, and GI tract; the bleeding it causes can be fatal.
Transplant-related KS occurs in transplant recipients who are taking immunosuppressive medications and can improve if the drugs are reduced or stopped. Transplant-related KS rarely causes death, but left unattended, it, too, can result in fatal bleeding.
Cutaneous KS usually manifests as red-purple papules and plaques capable of evolving into tumors or nodules. Lymphedema is less common. The exact pathogenesis is unknown.
Lower-limb lymphedema due to HIV-associated KS demonstrates variable fibrosis, hemosiderin deposits, lymphocytes, plasma cells, interstitial granular material, and pools of lymph. Slitlike vascular spaces and hemosiderin mark KS. Hengge proposed that HHV-8-induced lymphatic-vessel obstruction with resultant lymphadenopathy, as well as the hyperkeratotic variant of KS, is the result of high interstitial protein content, retention of fluid in connective tissue with associated chronic inflammation, and synthesis of pleiotropic growth factors.
A new immunostain for HHV-8 is 100% sensitive for KS. Spindle cells are thought to be the proliferative component of KS, while endothelial cells are thought to undergo a reactive hyperplasia. Some authors have suggested that the spindle-cell elements show endothelial differentiation. Chronic stimulation of endothelial cells (possibly by viral infection) can produce differentiation to spindle-shaped cells.
For AIDS-associated KS, the best treatment is raising the CD count. If this is not possible because of HIV resistance to antiretroviral therapies, other treatments exist. Alitretinoin is a retinoid used to treat KS of the skin. Internal KS is often treated with chemotherapy (frequently using liposomal doxorubicin), radiation therapy, and biological therapy (often using interferon). Surgery is rarely used to treat internal KS.
Our patient remains in treatment. His KS continues to abate even though his HIV is now resistant to all antiretroviral therapies, including raltegravir, the first integrase strand transfer inhibitor, and maraviroc (Selzentry), the first CC chemokine receptor 5 blocker. Hypopigmentation in his plaque, a side effect of cryotherapy, is repigmenting.
Dr. Scheinfeld is assistant clinical professor of dermatology at Columbia University in New York City, where he has a private practice.
■ Hengge UR, Ruzicka T, Tyring SK, et al. Update on Kaposi’s sarcoma and other HHV8 associated diseases. Part 1: epidemiology, environmental predispositions, clinical manifestations, and therapy. Lancet Infect Dis. 2002;2:281-292.
■ Hengge UR, Ruzicka T, Tyring SK, et al. Update on Kaposi’s sarcoma and other HHV8 associated diseases. Part 2: pathogenesis, Castleman’s disease, and pleural effusion lymphoma. Lancet Infect Dis. 2002;2:344-352.