Dark Topics on Giant Retroperitoneal Liposarcoma: A Systematic Review of 157 Cases

BACKGROUND/OBJECTIVES: Giant Retroperitoneal Liposarcomas (giant RPLs) represent a rare malignant disease of adulthood that does not yet have a univocal definition in the scientific literature. The symptoms may be late, depending on the position and the size reached. The weight may exceed 20 kg, and the diameter 25 cm. The main treatment is the surgical approach. This systematic review aims to collect data from the present literature and to answer some questions on the nature of this pathology. METHODS: We performed a search on the PubMed, Cochrane, and Scopus databases using specific search strings. Non-English written articles and abstracts were excluded. RESULTS: Dimensional, histological, and pathological data of giant RPLs were extracted and recorded in an electronic database, and charts were used to synthesize the results. We selected 126 manuscripts, all case reports and case series, and obtained data for 157 giant RPLs. The major axis varied from 15 to 80 cm, and the weight ranged between 2.5 and 98 kg. Sex distribution was homogenous. Age was reported 146 times, and almost 1/3 of the study population was under 50 years old. The most frequent hystotype reported was well-differentiated liposarcomas, while the rarest was pleomorphic liposarcomas. In 139 cases, the symptoms were reported and generally included a mass effect on surrounding organs. The exclusive surgical operation was the most frequent treatment option, and it included both the resection of the tumor and other organs involved. Chemo- and radiotherapy were also performed, in a few cases. In 36 reports, distant metastasis was suspected, but only 6 were effectively positive. CONCLUSIONS: Giant RPLs are a clinical entity that shares some common features with normal-size liposarcomas but are different in dimensions, age distribution, histologic prevalence, rate of incidental diagnosis, organ sparing, and R0 resection. More studies are needed to completely characterize these tumors.