Pan-TRK positive uterine sarcoma in immunohistochemistry without neurotrophic tyrosine receptor kinase gene fusions: A case report

Figure 1  Colposcopic images of the cervical mass from the patient.

Figure 2 Imaging at diagnosis. A: Pelvic and chest computed tomography; B: Pelvic magnetic resonance imaging; C: Positron emission tomography-computed tomography. A 5 cm mass with necrosis in the uterine cervix is observed (arrows, yellow), along with multiple peritoneal seeding in the right paracolic gutter (arrows, orange) and a large amount of ascites. T2WI: T2 weighted image; T1WI: T1 weighted image; DWI: Diffusion weighted image; ADC: Apparent diffusion coefficient.

Figure 3 Liquid-based cytology detected ovoid to round cells with hyperchromatic nuclei. Immunohistochemistry exhibited diffuse strong positivity for pan-TRK. A and B: Low power view of uterine cervix (A) (Papanicoalu stain, × 40) A cluster of atypical cells with clumped chromatin is observed, and some cells with low cohesion are scattered individually (B) (Papanicoalu stain, × 100); C and D: The tumor cells were ovoid to round cells with hyperchromatic nuclei formed loosely cohesive clusters without keratinization (C) (Papanicoalu stain, × 400). Pan-TRK staining showed diffuse strong positivity in cytologic specimen (D) (× 400).

Figure 4 Pan-TRK staining was positive. A and B: Infiltrating tumor cells in a sheet pattern were observed in cervical biopsy (A) [hematoxylin-eosin (HE) stain, × 40]. Round or oval cells have a vesicular nucleus and distinct nucleoli. Mitotic activities were commonly observed and there were also some necrotic areas (arrow) (B) (HE stain, × 400); C: As in the cytology specimen, pan-TRK staining was positive (× 200).

Figure 5 Post-chemotherapy imaging. A follow-up pelvic computed tomography showed substantial improvement with only minimal residual peritoneal seeding remaining (arrow).

Figure 6 Algorithm for diagnosing NTRK gene fusion in cervical sarcoma. NGS: Next-generation sequencing; IHC: Immunohistochemistry.