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Question 24#

A 34-year-old homosexual man with a history of HIV presents to the clinic complaining of wheezing and multiple violaceous plaques and nodules on his trunk and extremities. Physical examination of the oral mucosa reveals similar findings on his palate, gingiva, and tongue. Chest x-ray is also significant for pulmonary infiltrates.

What is the most likely pathogenesis of this process? 

a. Proliferation of neoplastic T cells
b. Infection with human herpesvirus 6
c. Infection with Mycobacterium avium due to decreasing CD4 count
d. Angioproliferative disease caused by infection with human herpesvirus 8
e. Disseminated herpes simplex infection

Correct Answer is D

Comment:

This patient has Kaposi sarcoma (KS). In HIV-infected individuals, KS is associated with human herpesvirus 8 (HHV-8). KS lesions are derived from the proliferation of endothelial cells in blood/lymphatic microvasculature. They present as violaceous patches, plaques, and/or nodules on the skin, mucosa, and/or viscera. The pulmonary infiltrates observed on the chest x-ray of this patient are the result of visceral KS affecting the lungs. KS has become uncommon in the era of highly active antiretroviral therapy (HAART). Proliferation of neoplastic T cells is seen in cutaneous T-cell lymphomas such as mycosis fungoides. Human herpesvirus 6 (HHV-6) is the cause of exanthema subitum (roseola) in children. It consists of 2- to 3-mm pink macules and papules on the trunk following a fever. Mycobacterium avium causes fever and weight loss in HIV patients with a CD4 count less than 50/µL. Immunodeficient patients or patients with HIV who are infected with HSV can present with the disseminated form of the disease. However, these lesions consist of a vesicular rash that is different from the violaceous plaques observed in KS.