A giant solitary fibrous tumor of the pleura: diagnostic implications in an unusual case with literature review.

A solitary fibrous tumor of the pleura (SFTP) is an uncommon tumor, in contrast to a relatively common mesothelioma in pleura. Its average size varies from 6 to 8 cm. We report herein a case of a giant SFTP in a 53-year-old man who presented with cough since five years along with chest pain on the left side and progressive dyspnea since two months. Radiological findings revealed a large pleural mass measuring 25 cm in its largest dimension, filling the pleural cavity with effusion. Biopsy showed a spindle cell tumor with areas of dense sclerosis. Subsequent excision unraveled a large multinodular, grey-white tumor, histologically, composed of spindle cells in a 'patternless' arrangement in dense collagenous stroma with areas of hyalinization. Focal areas showed hypercellularity with atypia and mitoses, but less than 4/10 High-Power Field, unassociated with necrosis. On immunohistochemistry, tumor cells showed diffuse positivity with vimentin, CD34 and BCL2 along with cytoplasmic positivity for MIC2 (CD99), whereas cytokeratin, EMA, calretinin and HBME-1 were negative. Diagnosis of an SFTP was substantiated over a close differential of a desmoplastic mesothelioma. In view of atypical features, a close follow-up of the case was recommended.