Clinicopathologic Study of 39 Mismatch Repair-deficient Sarcomas Demonstrates Recurrent Histologic Patterns and Supports Universal Screening of Pleomorphic Rhabdomyosarcoma, Uterine Leiomyosarcoma, and Undifferentiated Sarcomas.

Recurrent histologic patterns in dMMR sarcomas and recommendation for universal MMR screening in 3 specific subtypes

This American Journal of Surgical Pathology study characterizes 39 MMR-deficient (dMMR) sarcomas including 21 MSH2, 9 MLH1, 4 PMS2, 4 MSH6, and 1 EPCAM. Eight were index neoplasms in 15 patients with documented Lynch syndrome. Recurrent histologic patterns are identified, and universal MMR-IHC screening is recommended for three subtypes: pleomorphic rhabdomyosarcoma, uterine leiomyosarcoma, and undifferentiated sarcomas.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

Sarcomas are a rare but real Lynch syndrome presentation, often missed because MMR-IHC is not systematic outside digestive and gynecological tumors. This study provides the argument to extend screening to three specific subtypes — a directly applicable practical recommendation for pathologists.

Clinical impact: 2/3 · Evidence strength: 2/3 · Novelty: 1/2 · Sample size: 0/1 · Publication status: 1/1 → Total: 6/10