Abstract
BACKGROUND: Signet ring cell carcinoma originating from the appendix is extremely rare, and the lack of specific clinical symptoms and imaging features makes preoperative diagnosis particularly challenging. CASE SUMMARY: We report a case of a 49-year-old woman who presented with irregular vaginal bleeding lasting more than five months. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed an enlarged appendix with a thickened wall and progressive enhancement after contrast administration. The uterine myometrium and cervix were markedly thickened, with heterogeneous density and signal intensity, along with progressive enhancement. The uterine serosal surface remained intact. Preoperative MRI suggested diffuse uterine adenomyosis; however, postoperative histopathology confirmed Signet ring cell carcinoma originating from the appendix with implantation involving the entire uterus. CONCLUSION: Imaging showed appendiceal wall thickening and marked thickening of the uterine myometrium, with lesions demonstrating progressive enhancement after contrast administration. These findings should raise suspicion for the implantation of Signet ring cell carcinoma originating from the appendix and involving the uterus. Signet ring cell carcinoma originating from the appendix is relatively rare, and its imaging features are seldom reported, making preoperative diagnosis extremely challenging. This study retrospectively analyzes a case of Signet ring cell carcinoma originating from the appendix with implantation involving the entire uterus. The imaging characteristics of the appendix and the uterus were evaluated using CT and MRI to enhance awareness of this disease.