Liposarcomas in Young Patients

Abstract

Liposarcomas typically occur in middle aged to older adults. Altogether, approximately 50 bona fide liposarcomas have been reported in children and adolescents, most of which have represented myxoid liposarcomas, with a good prognosis. We undertook a retrospective study of 82 liposarcomas occurring in patients below 22 years of age. Clinicopathologic and follow-up information was obtained. Fluorescence in situ hybridization for FUS, EWSR1, CHOP (DDIT3), and MDM2 was performed in 30 cases. The tumors occurred in 28 males and 54 females (5 to 22 y of age) and involved many locations. Fifty-six cases were typical myxoid liposarcomas, including 2 with round cell areas. The tumors were grade 1 (56 cases) and grade 3 (2 cases). Thirty-seven of 38 patients with follow-up are alive without disease and 1 is alive with disease (median 59 mo follow-up duration, range: 8 to 108 mo). Six cases showed myxoid liposarcoma with spindled growth ("spindle cell myxoid liposarcoma"); these arose in 5 females and 1 male (median age 14 y) and involved the thigh in 40% of cases. All were grade 1. Follow-up (4 of 6 patients) showed local recurrences in 2 cases and metastases in 1 case. Twelve tumors consisted of conventional myxoid liposarcoma and pleomorphic liposarcoma ("pleomorphic myxoid liposarcoma"); these arose in 4 males and 8 females (10 to 22 y of age) and often involved the mediastinum. Tumor grades were 2 (4 cases) and 3 (8 cases). Follow-up (10 patients) showed 7 dead of disease, 1 alive with disease, and 2 disease free. Four atypical lipomatous tumors were seen including 2 with low-grade dedifferentiation. Two local recurrences were seen; all patients are disease free. Two conventional pleomorphic liposarcomas were seen; 1 patient with follow-up is disease free. FUS-CHOP and EWSR1-CHOP rearrangements were identified by fluorescence in situ hybridization in 15/23 and 2/23 conventional myxoid liposarcomas, respectively, and in no other tumors. Amplification for MDM2 was absent in all cases. We conclude that conventional myxoid liposarcoma is by far the most common subtype of liposarcoma in young patients, with an excellent prognosis. Two apparently novel subtypes of liposarcoma, termed pleomorphic myxoid liposarcoma and spindle cell myxoid liposarcoma comprise considerable percentages of liposarcomas in this age group and should be distinguished from conventional myxoid liposarcoma and conventional pleomorphic liposarcoma. Pleomorphic myxoid liposarcoma and spindle cell myxoid liposarcoma most likely represent high-grade and low-grade variants of myxoid liposarcoma, respectively. Additional study of such cases will be necessary for definitive classification.

Involvement of the PI3K/Akt pathway in myxoid/round cell liposarcoma

“…These specimens comprised 43 biopsies and 127 resection specimens. An additional 18 tumors with unusual morphology (marked spindling, pleomorphism)(20), or where the diagnosis could not be definitively made on histologic review were excluded from the study, as were 10 cases with no viable tumor. Clinical information including demographic, tumor and therapeutic information was retrieved from patient medical records and from the UTMDACC soft tissue tumor database, and tabulated for correlative analysis.…”

Prostatic Adenocarcinoma Metastatic to Pleomorphic Liposarcoma, a “Collision Phenomenon”: Report of a Case with Review of Pelvic Collision Tumors

“…It is also of interest that this CHOP FUS -positive poorly differentiated myxoid liposarcoma did not contain the round cell component associated with myxoid liposarcoma, but this has been described to occur in some myxoid liposarcomas [36]. …”

Myxoid liposarcoma in a 91-year-old patient

“…Myxoid liposarcoma tends to occur on extremities, with two thirds of cases originating in the thigh [2]. This disease affects a younger demographic than most cancers with peak incidence between ages 30–50 [1], and is the most common subtype of liposarcoma in the pediatric age group [3]. …”