Histopathologic review of 400 biopsies and resection specimens of trunk and extremity-based soft tissue tumors

To review various pathologic parameters in diagnosed cases of trunk and extremity-based soft tissue tumors (STTs), in order to identify concordance rate between initial biopsy and resection specimen and discrepancies between initial and review diagnosis, by a specialist pathologist.

Over a 2-year-period, 400 retrospectively diagnosed STTs (553 specimens) including referral and "in-house" cases were studied. The reviewing specialist pathologist was blinded to the initial diagnoses. Discordances including discrepancies and deficiencies were defined as major and minor. Major discrepancies included those that could lead to significant treatment changes. True discrepancies were those related to sampling issues between the biopsies and resection specimens. Deficiencies relating to tumor subtyping, sarcoma grading, documentation of tumor size, and marginal status (in resections) were subdivided as major and minor.

Most cases (328, 82%) were sarcomas (most common, synovial sarcoma; most common Stage, III), followed by benign tumors (36, 9%) (most common, schwannoma) and intermediate malignancies (32, 8%) (most common, fibromatosis). Within STTs, liposarcomas, neural tumors, and undifferentiated pleomorphic sarcomas were relatively more frequently associated with discrepancies. Percentage of cases with major discordances between the referral reports (100 cases) and review diagnosis was 60%. Percentage of cases with major discordances between the specialist and other oncopathologists was 11%. True discrepancies were observed in 20 (5%) cases. The association of type of specimen with the rate of discordance was not significant (P = 0.114).

Diagnoses of STTs are fraught with errors mostly from general pathologists, followed by nonspecialist oncopathologists. These findings reinforce the need for reporting of STTs, especially sarcomas, by specialist pathologists.