Localized fibrous tumor of the pleura: immunohistochemical and flow-cytometric DNA study.

ABSTRACT

This report describes three cases of localized fibrous tumor of the pleura (LFTP) with clinical and pathological differences. Case 1 presented 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 were 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 mesenchymal origin. Flow cytometry quantitation of DNA disclosed a diploid pattern in all three cases with a small "near diploid" cell population additionally in Case 1; the S-phase fraction was low in all cases. These findings, that could be considered favourable prognostic signs, and the complete tumoral resection performed in the three tumors, could explain the absence of recurrences after 32, 27 and 19 months, respectively.