HIGH-RESOLUTION COMPUTED-TOMOGRAPHY AND PULMONARY CAPILLARY VOLUME INPATIENTS WITH PROBABLE PULMONARY KAPOSIS-SARCOMA

Objective : pulmonary Kaposi's sarcoma (KS) remains difficult to diagn ose because of the poor specificity of clinical and radiological signs and the low yield of biopsies. Computed tomography (CT) has been used to describe characteristic aspects of pulmonary KS, and high-resoluti on CT (HRCT) may be able to depict more precise features. An increase in pulmonary capillary volume has been reported in patients with cutan eous KS. Design and patients : in a prospective study, we determined t he specificity of HRCT for pulmonary KS and divided 51 HIV patients in to four groups, as follows : 10 asymptomatic patients without KS (cont rol group 1), 14 patients with cutaneous KS (control group 2), 15 pati ents with mucocutaneous KS (control group 3) and 12 patients with prob able pulmonary KS (group 4) documented by HRCT and/or bronchoscopy. Ma jor patterns of probable pulmonary KS i.e spiculated nodules and perib ronchovascular thickenings were precisely described. Pulmonary functio n tests (PFT) were done in every case. Results : total lung capacity ( TLC), transfer lung capacity (DLco) and its components: pulmonary capi llary volume Vc and membrane factor DM were not different in the 4 gro ups. Forced expiratory volume for one second over vital capacity (FEV1 /VC) was significantly lower in control group 2 and in group 4 than in control groups 1 and 3. DLco was normal in patients with pulmonary KS (group 4); no significant change in DM (mean = 71.5 +/- 17.5% of pred icted values) or Vc (mean = 83.6 +/- 14.1% of predicted values) was ob served. Conclusions : these results show that Vc alone is unsuitable f or the early diagnosis of pulmonary KS, but that HRCT combined with br onchoscopy can yield findings strongly suggestive of pulmonary KS and obviate the need for more invasive investigations.