NTRK-Fusion Sarcoma of the Uterine Cervix: Report of 2 Cases With Comparative Clinicopathologic Features.

NTRK1/2/3 rearrangements have been identified as oncogenic drivers in a variety of tumors including those in the uterine cervix, and rarely, the uterine corpus. We report 2 cases of cervical sarcoma with NTRK gene rearrangements. Case 1 was a 54-yr-old woman who presented with postmenopausal bleeding and a 5.4 cm friable mass in the cervix. Microscopic examination of the tumor revealed proliferation of epithelioid and spindle cells arranged in alternating hypercellular and hypocellular areas, with subtle fibrosarcoma-like features. Coagulative tumor cell necrosis and readily recognizable mitoses (up to 40 mitotic figures per 10 high-power fields) were identified. Case 2 was a 52-yr-old woman who presented with abnormal vaginal bleeding and a 1.3 cm cervical mass. The resected cervical tumor showed proliferation of spindled cells with fascicular and storiform growth pattern, infiltrating into the smooth muscle with entrapment of normal endocervical glands. The tumor cells displayed mild cytologic atypia and low mitotic activity (1 mitotic figure per 10 high-power fields). The mixed inflammatory infiltrate was seen throughout the lesion, mimicking morphology of inflammatory myofibroblastic tumor. Immunohistochemical staining for S100 and CD34 demonstrated variable expression in case 1 and uniformly diffuse positivity in case 2. The tumor cells in both cases were focally positive for CD10, Cyclin D1, ER, and PR, and negative for AE1/AE3, desmin, SOX10, HMB-45. RNA fusion analysis identified SPECC1L-NTRK3 gene rearrangements in case 1 and TPM3-NTRK1 in case 2; DNA-based mutational analysis also revealed CDKN2A/B homozygous deletion in case 1. Despite accumulating literatures on NTRK fusion mesenchymal tumors in gynecologic pathology, these tumors are still rare and lack well-established morphologic diagnostic criteria. Diagnostic and clinical recognition of these tumors is critical given the potential patient benefit from targeted therapy.