Primary NTRK-rearranged spindle cell sarcoma of the colon with ETV6-NTRK3 fusion.
Yuan-Yin Zheng, Ying-Yu Mao, Mao-Hua Lin et al.
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Case in brief
A man in his late 30s presented with abdominal pain, leading to a CT scan that revealed a large transmural tumor in the colon. The multidisciplinary team opted for immediate surgery without preoperative colonoscopy. Histopathology and next-generation sequencing confirmed a spindle cell neoplasm with an ETV6-NTRK3 fusion. Following a complete resection, the patient declined adjuvant chemotherapy and remained recurrence-free at 8 months.
What made this case unusual
The case highlights an unexpected strong CD31 positivity in the tumor, which is not typically associated with spindle cell sarcomas and requires further validation.
Diagnostic / clinical pearl
Molecular confirmation of NTRK fusions is crucial for accurate diagnosis and potential eligibility for targeted therapies in spindle cell sarcomas.
Why it matters
This case contributes to the understanding of gastrointestinal NTRK-rearranged sarcomas, emphasizing the need for awareness of atypical immunohistochemical findings.