Pleomorphic liposarcoma: A clinicopathologic analysis of 19 cases

Pleomorphic liposarcoma is a variant of liposarcoma defined morphologically by the presence of pleomorphic lipoblasts. Because of its rarity, there ar e limited studies with long-term follow-up information. Nineteen pleomorphi c liposarcomas were studied. Unequivocal pleomorphic lipoblasts were requir ed for inclusion. In each-case, the following features were noted: tumor si te; tumor size; tumor depth; predominant histologic pattern (epithelioid or malignant fibrous histiocytoma [MFH]-like); extent of necrosis (absent, le ss than 15%, or at least 15%); mitotic counts; treatment and clinical follo w-up. Patients were 11 females and 8 males, aged 33-87 years (mean, 64.5 y; median, 70 y). Tumors involved the extremities (13 patients: intramuscular in 10, subcutaneous in 2, depth unknown in 1), retroperitoneum (4 patients ), mediastinum (1 patient), and paratesticular region (1 patient). Size ran ged from 4.5-31 cm (mean, 11.9 cm; median, 12.0 cm). Predominant pattern wa s epithelioid in 7 and MFH-Iike in 12. Necrosis was present in 15 (79%) and was extensive (36 15%) in 14 patients. Mitotic counts ranged from 0.2-3.4/ 10 high-power fields (mean, 1.4; median, 1.4) by the average-count method a nd from 1-6/10 high power fields by the highest count method (mean, 2.9; me dian, 3.0). All patients were treated surgically; 10 patients received adju vant chemotherapy and/or radiation therapy. On follow-up of 18 patients (ra nge, 2-129 mo; mean, 35.4 mo; median, 23 mo) nine (50%) were dead of diseas e (range, 2-48 mo; mean, 20.1 mo; median, 12 mo), one died of other causes 2 months after diagnosis, two were alive with disease, five were disease fr ee, and one was alive at 129 months (tumor status unknown). Five had recurr ences (range, 3-28 mo; mean, 14.4 mo; median, 8 mo), and four of five (80%) with recurrences were dead of disease. Metastases developed in eight patie nts (range, 4-48 mo; mean, 19.5 mo; median, 11.5 mo), most commonly to the lungs. In conclusion, pleomorphic liposarcoma is a rare tumor of adulthood that occurs most commonly in the deep, soft tissues of the extremities. It behaves as a high-grade sarcoma that frequently metastasizes, most commonly to the lungs. Although this tumor has a wide range of histologic appearanc es, no clinical or pathologic feature is predictive of a more aggressive cl inical course.