Well-Differentiated Inflammatory Liposarcoma: An Uncommon and Easily Overlooked Variant of a Common Sarcoma

Abstract

The presence of abundant inflammation is uncommon in well-differentiated liposarcomas (WDLPS). We describe ten cases of WDLPS in which an extensive lymphoplasmacytic infiltrate was present to such a degree that the differential diagnoses included inflammatory pseudotumor and Castleman's disease, and in which the lipogenic component could easily be overlooked. The median age (62 years) and tumor location (six retroperitoneal, three head/neck, one paratesticular) was comparable to usual WDLPS, as was the fact that six of ten cases recurred locally, but none metastasized during the period of follow-up (range 13 to 228 months, median 72 months). Key histologic features included (1) nodular lymphoplasmacytic aggregates; (2) intervening paucicellular stroma containing fibroblastic elements, frequently with plasma cell-rich zones and scattered atypical, often multinucleate cells; (3) merging of atypical adipocytic and inflammatory elements; and (4) adjacent clearly defined zones of lipoma-like or, more rarely, sclerosing-type liposarcoma. In recurrences, two cases "reverted" to purely lipoma-like liposarcoma, and two cases dedifferentiated. Immunoperoxidase studies demonstrated that B cells predominated in the lymphoid aggregates, and that the abundant plasma cells were polytypic in nature. We support the use of the term well-differentiated inflammatory liposarcoma for tumors of this type, which should be distinguished from high-grade liposarcoma containing inflammatory cells, and in order to identify a subgroup of WDLPS at high risk for misdiagnosis.

Giant Inflammatory Variant of Well-Differentiated Liposarcoma of Retroperitoneum: A Rare Case Report

“…Merging of atypical adipocytic and inflammatory elements, 4. Adjacent clearly defined zones of lipoma-like, or more rarely, sclerosing-type liposarcoma, all of which were seen in our case [8].…”

Liposarcoma: A Clinicopathological Study of 73 Cases Diagnosed at King Faisal Specialist Hospital and Research Centre

“…Welldifferentiated liposarcoma almost never metastasizes unless dedifferentiation occurs. 2,4,7,8 In our study, only two out of 16 cases (12.5%) with well-differentiated liposarcoma recurred after six and seven years of initial diagnosis, respectively. The survival for pleomorphic and round cell types is 20%, with a higher rate of local recurrence (80%) than well-differentiated liposarcoma (50%).…”

“…Their behavior is strongly influenced by location, with retroperitoneal lesion having the worst prognosis. 1,8,9 As a long-term complication of the disease, these lesions may progress histologically (dedifferentiate), increasing their metastatic potential. Dedifferentiated liposarcomas can arise de novo, and occur most commonly in the retroneritoneum.…”

Liposarcoma of the spermatic cord

“…При этом варианте хронический воспалительный инфильтрат иногда настолько выражен, что липогенная природа опу-холи может быть скрыта, поэтому для гистологического исследования необходимо брать большое количество фрагментов. В таких случаях дифференциальный диагноз проводится с липогранулематозным воспалением и нели-пидогенными опухолями, такими как воспалительная мио-фибробластическая опухоль, болезнь Кастлемана, лим-фома Ходжкина и неходжкинские лимфомы [21][22][23].…”