Added Value of Molecular Biological Analysis in Diagnosis and Clinical Management of Liposarcoma: A 30-Year Single-Institution Experience

Treatment decisions and prognosis assessment for liposarcoma is based on a classification that depends on morphological and genetic features. Revisions by experienced referral pathologists are often advocated. The process of histopathological classification in referring hospitals and subsequently in a referral center in relation to molecular biological information is evaluated. A total of 331 consecutive liposarcoma patients were evaluated for the added value of histological review at time of referral. Subsequently, cases were reclassified with implementation of present-day molecular information. For all patients, complete data on staging, treatment, and follow-up were available. Upon histological revision, 15/54 (28%) diagnoses were reclassified in the first decade, 14/65 (22%) in the second, and 14/53 (26%) in the last decade. Molecular biological analysis enabled well-differentiated liposarcoma with or without dedifferentiated component to be better recognized as such and distinguished from myxoid liposarcoma and pleomorphic liposarcoma. Inclusion of cytogenetic information resulted in reclassification after revision in 4/18 (22%) cases in the first decade, 10/38 (26%) cases in the second decade, and 19/75 (25%) cases in the last decade. This study indicates that liposarcomas are heterogeneous tumors. Expert assessment and implementation of molecular biological analysis are valuable for adequate classification as a basis for treatment decisions.