LOCALIZED FIBROUS TUMOR OF THE PLEURA - IMMUNOHISTOCHEMICAL AND FLOW-CYTOMETRIC DNA STUDY

This report describes three cases of localized fibrous tumor of the pl eura (LFTP) with clinical and pathological differences. Case 1 present ed with symptoms; the tumor size was 6.5 cm and it was attached to the lung and chest wall; histologically it was composed of spindle cells with pleomorphism, mitoses, hemorrhage and necrosis. Cases 2 and 3 wer e casual findings and consisted of well-circumscribed tumors of 3 and 8.5 cm, respectively; histologically both showed hypocellularity. All cases exhibited positive stains for vimentin and negative for keratin. These results, added to histological features, suggested a mesenchyma l origin. Flow cytometry quantitation of DNA disclosed a diploid patte rn in all three cases with a small ''near diploid'' cell population ad ditionally in Case 1; the S-phase fraction was low in all cases. These findings, that could be considered favourable prognostic signs, and t he complete tumoral resection performed in the three tumors, could exp lain the absence of recurrences after 32, 27 and 19 months, respective ly.