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NTRK-rearranged spindle cell neoplasm: Initial observation of imaging appearance and clinicopathologic correlation
Matthew Spano1, Cecilia Davis-Hayes1, Meera Hameed1
1Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, United States of America.
Objective:
To explore pre-treatment imaging findings of neurotrophic tyrosine receptor kinase (NTRK)-rearranged spindle cell neoplasm, an emerging group of molecularly defined soft tissue tumors and summarize the clinical course, including TRK inhibitor therapy response.
Materials And Methods:
This retrospective study included 8 women and 4 men with NTRK-rearranged spindle cell neoplasm (median age, 35.5 years, range, 0-66). Available pre-treatment MRI, CT, PET, and US imaging were reviewed. Tumor histology and the patients' clinical course were reviewed.
Results:
Primary tumors were located within the soft tissue, lungs, kidney, and breast with soft tissue being the most prevalent site (n = 6). Pre-treatment MRI (n = 4) revealed linear hypointense signal foci and contrast enhancement in all patients with hemorrhage in half of the tumors. A tail sign (n = 1) and fluid levels (n = 1) were less frequent. Ultrasound showed well-marginated hypoechoic masses with internal flow. Primary tumors were all non-calcified on CT (4/4). Metastases were FDG-avid (4/4). Among the 8 patients who developed metastasis, 7 developed pulmonary metastases. All four patients who received NTRK inhibitor therapy showed an initial decrease in tumor size or FDG uptake.
Conclusion:
NTRK-rearranged neoplasms may occur as enhancing masses with linear hypointense signal foci on MRI and FDG avid metastases on PET. Pulmonary metastases were frequent in our study. Initial treatment response is observed in most patients.
Insights
Neurotrophic tyrosine receptor kinase (NTRK)-rearranged spindle cell neoplasms present as enhancing masses on MRI and are FDG-avid on PET scans. These tumors often metastasize to the lungs and show initial response to TRK inhibitor therapy.
Area of Science:
- Oncology
- Radiology
- Molecular Pathology
Background:
- Neurotrophic tyrosine receptor kinase (NTRK)-rearranged spindle cell neoplasms are an emerging class of molecularly defined tumors.
- Understanding their imaging characteristics and clinical behavior is crucial for diagnosis and management.
Purpose of the Study:
- To investigate the pre-treatment imaging features of NTRK-rearranged spindle cell neoplasms.
- To summarize the clinical course and response to TRK inhibitor therapy.
Main Methods:
- Retrospective analysis of 12 patients (8 women, 4 men) with NTRK-rearranged spindle cell neoplasm.
- Review of pre-treatment MRI, CT, PET, and ultrasound imaging.
- Analysis of tumor histology and patient clinical course, including treatment response.
Main Results:
- Primary tumors most commonly occurred in soft tissue (n=6).
- MRI revealed linear hypointense foci and enhancement; hemorrhage was noted in half.
- Metastases were FDG-avid on PET (4/4), with pulmonary metastases being frequent (7/8).
- All four patients receiving NTRK inhibitor therapy showed initial tumor shrinkage or reduced FDG uptake.
Conclusions:
- NTRK-rearranged neoplasms can manifest as enhancing masses with specific MRI findings and FDG-avid metastases.
- Pulmonary metastases are a common presentation.
- Initial response to TRK inhibitor therapy is frequently observed.
