Diagnosis of primary fibrosarcoma of the lung by fine-needle aspiration and core biopsy: A case report and review of the literature

Primary pulmonary sarcomas are uncommon neoplasms. Primary fibrosarcoma of the lung is extremely rare, and only 53 cases have been documented in the literature to date. To our knowledge, the diagnosis of primary lung fibrosarcoma by fine-needle aspiration cytology has never been reported. We report a case of pulmonary fibrosarcoma diagnosed by fine-needle aspiration cytology and core biopsy. The neoplasm consisted of interweaving fascicles of minimally atypical spindle cells with slender nuclei and scant cytoplasm. Positive immunohistochemistry for vimentin along with nonreactivity of tumor cells for keratin, S100 protein, desmin, α-smooth muscle actin, and CD34 supported the the diagnosis. The diagnosis was later confirmed by histologic and ultrastructural findings following lobectomy. A meticulous clinical search for a possible primary neoplasm elsewhere was unsuccessful, and lung was established as the primary site. Fine-needle aspiration cytology and core biopsy are reliable methods for establishing a diagnosis of fibrosarcoma.