Pleural liposarcoma mimicking carcinoma in pleural effusion cytology: a case report

Primary pleural liposarcoma is extremely rare, and its most common subtype is the myxoid subtype. To the best of our knowledge, the number of cases reported up to now is <20. It is primarily a disease ofindividuals 50 years of age and it is more common in men. It has no specific symptoms except for cough and chest pain.

A 56-year-old female presented complaining of chest pain and dyspnea for 4 months. An increase in homogeneous density on the left hemithorax, from the apex to basal area, with blurring of the borders of the heart and the diaphragm, was revealed by lung radiography. Thoracic computed tomography revealed a diffuse pleural effusion causing compressive atelectasis at the base of the left hemithorax. Cytologic examination of the pleural fluid demonstrated tumoral cells forming papillary structures with complex branching and fine fibrovascular core. The tumor cells were relatively uniform and had vacuolar cytoplasm with hyperchromatic nuclei. Upon finding CA-125 positive in the immunocytochemical examination, the case was reported as "consistent with malignancy, possibility of ovarian origin, cannot be excluded". As the gynecologic examination was normal, exploratory thoracotomy was performed to take a biopsy. The case was diagnosed as liposarcoma (myxoid type) by histopathologic examination.

Cytologic diagnosis of pleural liposarcoma is difficult due to its rarity and resemblance to malignant mesothelioma. Cytologic properties of liposarcoma in pleural fluid should be well known and considered in the differential diagnosis.