Navigating Diagnostic Challenges in Epithelioid Sarcoma: Multidisciplinary Strategies to Optimize Diagnosis
Panelists discuss how recognizing the diagnostic challenges of epithelioid sarcoma—including its histologic overlap with other conditions and the importance of INI1 loss as a key marker—can improve early detection and reduce misdiagnosis of this rare and aggressive tumor.
Summary for Physicians: Diagnostic Challenges and Pitfalls in ES
Diagnosing epithelioid sarcoma (ES) is often challenging due to its rarity, variable presentation, and histologic overlap with other conditions. Common diagnostic pitfalls include misinterpreting ES as benign lesions, such as granulomatous inflammation or reactive processes, especially in the early stages. The tumor’s epithelioid appearance may also lead to misclassification as carcinoma or other soft tissue sarcomas.
Timely diagnosis is complicated by the typically indolent growth of ES, especially in the distal (classic) subtype, which can delay clinical suspicion. The proximal (large cell) subtype can mimic other high-grade sarcomas or poorly differentiated carcinomas due to its more aggressive features and deep-seated location.
ES is frequently misdiagnosed—often initially mistaken for infections, benign cysts, or other sarcoma subtypes. A key diagnostic marker is loss of INI1 (SMARCB1), which should be assessed in cases with ambiguous histology. Awareness of these diagnostic nuances and incorporating molecular testing early in the workup can significantly improve diagnostic accuracy.
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