Pleomorphic Liposarcoma: A Clinicopathologic Analysis Of 19 Cases

• Published in: Modern pathology 2001-03, Vol.14 (3), p.179-184
• Main Authors: Downes, Katharine A, Goldblum, John R, Montgomery, Elizabeth A, Fisher, Cyril
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Chemotherapy; Combined Modality Therapy; Female; Follow-Up Studies; Hospitals; Humans; Laboratory Medicine; Liposarcoma; Liposarcoma - classification; Liposarcoma - pathology; Liposarcoma - therapy; Male; Malignant fibrous histiocytoma; Medicine; Medicine & Public Health; Middle Aged; Necrosis; original-article; Pathology; Patients; Pleomorphic liposarcoma; Pleomorphic sarcoma; Radiation; Sarcoma; Soft Tissue Neoplasms - classification; Soft Tissue Neoplasms - pathology; Soft Tissue Neoplasms - therapy; Treatment Outcome; Tumors
• ISSN: 0893-3952; 1530-0285
• DOI: 10.1038/modpathol.3880280

Pleomorphic liposarcoma is a variant of liposarcoma defined morphologically by the presence of pleomorphic lipoblasts. Because of its rarity, there are limited studies with long-term follow-up information. Nineteen pleomorphic liposarcomas were studied. Unequivocal pleomorphic lipoblasts were required for inclusion. In each case, the following features were noted: tumor site; tumor size; tumor depth; predominant histologic pattern (epithelioid or malignant fibrous histiocytoma [MFH]-like); extent of necrosis (absent, less than 15%, or at least 15%); mitotic counts; treatment and clinical follow-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 ranged from 4.5–31 cm (mean, 11.9 cm; median, 12.0 cm). Predominant pattern was epithelioid in 7 and MFH-like 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 and from 1–6/10 high power fields by the highest count method (mean, 2.9; median, 3.0). All patients were treated surgically; 10 patients received adjuvant chemotherapy and/or radiation therapy. On follow-up of 18 patients (range, 2–129 mo; mean, 35.4 mo; median, 23 mo) nine (50%) were dead of disease (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 free, and one was alive at 129 months (tumor status unknown). Five had recurrences (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 patients (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 appearances, no clinical or pathologic feature is predictive of a more aggressive clinical course.