18F-FDG PET/CT diagnosis of gastric-type endocervical adenocarcinoma: A case report.

Gastric-type endocervical adenocarcinoma (G-EAC) is an uncommon human-papillomavirus-independent cervical malignancy that frequently presents with non-specific symptoms and carries a high risk of peritoneal dissemination. A 52-year-old postmenopausal woman presented with 10 days of spontaneous, irregular, vaginal bleeding of moderate volume. She denied abdominal pain, tenesmus, or constitutional symptoms. Tumor markers showed elevation of CA-125 (212.37 U/mL) and CA-199 (1793.93 U/mL). The patient underwent MRI examination, which showed isointense signal intensity on T1-weighted imaging (T1WI) and slightly higher signal intensity on T2-weighted imaging (T2WI) in the cervix, with a size of approximately 49 mm × 45 mm × 48 mm. The boundary with the adjacent uterine cavity was unclear, suggesting a cervical tumor lesion. The patient underwent further PET/CT examination, which revealed a soft-tissue cervical mass with mild to moderate 18F-FDG uptake with an SUVmax of 5.4, diffuse and nodular thickening of the greater omentum, peritoneum, and mesentery showing mild uptake with an SUVmax of 2.2, accompanied by abdominal and pelvic fluid accumulation. The patient underwent histopathological examination of cervical mass tissue, and the pathological diagnosis was primary gastric adenocarcinoma of the cervix. 18F-FDG PET/CT can comprehensively evaluate the whole body, detect distant lesions, and provide an accurate diagnostic basis. Therefore, it holds significant diagnostic value for G-EAC, which is relatively rare and easily overlooked in clinical practice. It can help nuclear medicine physicians avoid misdiagnosis or missed diagnosis.