(P 148) MOVING TOWARDS THE OPTIMIZATION OF DIAGNOSIS FOR PATIENTS WITH SARCOMA: A 10-YEAR REVIEW OF EXTERNALLY CONSULTED SARCOMA CASES IN A GENERAL ANATOMICAL PATHOLOGY SERVICE

Objective: Soft tissue sarcomas (STS) are rare, diagnostically challenging, malignant tumors with diverse histomorphologic, immunohistochemical and molecular features. In our practice, STS are reported in a general anatomical pathology practice with no formal subspecialized training in reporting these complex specimens. Our study was performed to look at the rate of external consultation (EC), along with other parameters including discordance rate, associated diagnostic delay with EC and extent of secondary work-up performed by the consultant for correct diagnosis.

Methods: The reports from 880 soft tissue sarcomas cases in the province of Saskatchewan between January 1, 2010, to December 31, 2020, were analyzed descriptively.

Results: Of the 880 cases reviewed in our database, 51.9% (n=457) cases were sent to 35 different North American institutions for expert opinion. The initial diagnosis and expert opinion were in full agreement for 182 cases (39.8%), while 194 cases (42.5%) had partial agreement and 66 cases (14.4%) had zero agreement. Of the cases that had zero agreement, 20 cases (4.4%) were initially diagnosed as malignant, with a benign opinion given by the expert; and 10 cases (2.2%) were initially diagnosed as benign, which were malignant upon expert review.

Conclusion: Soft tissue sarcomas are complex tumors that frequently require expert opinion and integration of ancillary techniques with histomorphologic features for definitive classification. A multidisciplinary, subspecialized approach to STS and availability of necessary ancillary tests would improve diagnostic accuracy. In centers where the case load would not support the full-time expertise of an STS multidisciplinary team, criteria should be developed to effectively utilize EC practices.