Pulmonary Kaposi Sarcoma as an Unusual Etiology of Acute Hypoxemic Respiratory Failure in the Era of Highly Active Antiretroviral Therapy: A Case Report

Kaposi sarcoma (KS) is caused by human herpesvirus 8 (HHV-8). Epidemic KS is described in the human immunodeficiency virus (HIV) population with acquired immune deficiency syndrome (AIDS). It primarily affects the skin, but it may uncommonly disseminate to involve extracutaneous sites such as the gastrointestinal (GI) tract, liver, and lungs. In this case report, the authors report a 26-year-old homosexual male who was admitted with acute hypoxemic respiratory failure. He was diagnosed with an HIV infection about five months before index presentation, and he was commenced on highly active antiretroviral therapy (HAART). Physical examination was remarkable for diffuse cutaneous nodules over the lower extremities, back, and oropharynx. Chest imaging revealed diffuse bilateral infiltrates, mediastinal adenopathy, and a persistent bilateral pleural effusion. Extensive diagnostic workup was negative for underlying infectious etiology. Transbronchial biopsy demonstrated proliferated spindle cells that stained positive for HHV-8 in keeping with pulmonary KS. Skin biopsies also concurred with the diagnosis of cutaneous KS. Interestingly, the cluster of differentiation 4 (CD4) count was 647 cells/mm(3), and HIV viral load (VL) was 500 copies/ml. This case demonstrated an atypical natural history of pulmonary KS in an HIV patient as pulmonary and disseminated mucocutaneous KS occurred with a relatively higher CD4 count (≥500 cells/mm(3)). It also reminds pulmonologists and infectious disease specialists to consider pulmonary KS as a differential diagnosis of acute hypoxemic respiratory failure in HIV patients, even in the absence of other clinical and laboratory criteria that define the AIDS stage.