흉막에서 발생한 악성 고립성 섬유성 종양의 세침흡인 세포학적 소견

초록

Solitary fibrous tumor (SFT) is a morphologically distinctive, uncommon neoplasm that most frequently arise in the pleura. The malignant form is rare and only 12% of SFT behave in a malignat fashin. The features cellular pleomorphism, increased cellularity, infiltrative growth pattern, and increased mitotic figures were significant features suggestive of malignancy. There are some reports of cytologic finding of SFT. However, there is no previous report about cytologic features of malignant SFT in the English literature. We report the cytologic features observed in fine needle aspiration biopsy obtained from malignant SFT, which shows cellular pleomorphism, increased cellularity and increased mitotic figures. A 70-year-old woman presented with dyspnea for 2 weeks. The chest CT scan revealed a round 13cm sized well defined mass in the right upper lobe of the lung with a broad pleural base. The cytologic features revealed highly cellular smears, with abundant, loosely dispersed or tightly packed spindle tumor cells. A few monolayered clusters of mesothelial cells were intermixed. Some tumor cell clusters had a three dimensional appearance. The tumor cells had short spindle cigar shped hyperchromatic nuclei with mild cellular pleomorphism. Mitoses are occaionally seen. The nucleoli are inconspicuous and the cytolplasm is scanty. After resection of the tumor, the tumor size is 13x11x4cm. Grossly it is well curcumscribed. The external surface is pink gray and smooth. The cut surface shows yellow gray, lobulated, firm and myxoid appearance with multifocal cystic change. Microscpically, the tumor were composed of spindle cells embedded in a collagen matrix. The tumor cells are multifocally high-cellular and showed mild pleomorphism and atypia. The number of mitoses is moderately increased. Although the tumor is well marginated, the tumor was diagnosed as malignant SFT because of hypercellularity, pleomorphism of tumor cells and increased mitotic activity.