[AIDS-related pulmonary Kaposi's sarcoma: role of high-resolution computerized tomography]

HIV-related Kaposi sarcoma (KS) is characterized by lesion multifocality, stronger progression and recurrent involvement of some internal organs. Pulmonary lesions are found in 18-47% of cases and not necessarily associated with skin involvement. Lung infections are potentially life-threatening and their early and prompt demonstration is a crucial step for both treatment planning and the prognosis of this severe disease. As a rapid recognition of a pulmonary condition leads to a complete or partial regression in at least 50% of cases, we investigated the role and the diagnostic yield of HRCT in depicting HIV-related KS.

The findings of thirty-nine patients with HIV-related pulmonary KS were retrospectively reviewed. We excluded the patients with associated diseases and incomplete radiologic findings and included 12 patients who had a chest radiograph and a HRCT scanning at least. HRCT showed parenchymal and subpleural micronodules (< 10 mm) and macronodules (> 10 mm), with the halo sign in some cases; perivascular and peribronchial infiltrates, linear or irregular opacities, pleural effusions and enlarged lymph nodes were also seen. Chemotherapy response was also evaluated.

All 12 patients had advanced AIDS. The chest films showed abnormal patterns, such as peribronchial and perivascular infiltrates which were most often in midlower pulmonary lobes (88.9%) and often symmetric. Nodules were depicted in 50% of cases and were often associated with peribronchial and perivascular infiltrates; they were always bilateral and characterized by the presence of macronodules in most cases. Eleven of 12 HRCT examinations were considered sufficiently accurate for evaluation, while a pleural effusion prevented lung assessment in one case. Peribronchial and perivascular infiltrates were the most frequent abnormal findings (83.3%), with bilateral involvement in 80% and mostly in the midlower lobes (90%). Parenchymal and subpleural nodules were depicted in 58.3% of cases and always had irregular borders; the halo sign was seen around the nodules in 2 cases and macronodules were found in 2 cases. Pleural effusions were seen in 3 cases and enlarged lymph nodes in 4. Lung KS diagnosis was always confirmed at pathology. The response to chemotherapy (ABV protocol) was evaluated in 5 patients: transient and definitive regressions were observed in 1 and 2 cases, respectively, and disease progression was seen in 2 cases.

HRCT allows the accurate assessment of pulmonary KS in its different stages detailing the disease and its spread, which makes biopsy easier. It also permits to avoid more invasive diagnostic procedures and it is useful in the follow-up after chemotherapy.