Primary signet ring cell carcinoma of the appendix: An interesting case

A 66-year-old female patient came to our hospital due to abdominal distension and discomfort, which was relieved when standing up and lying down, without vaginal bleeding or fluid flow. There was no special personal history, past history, or family history. An enhanced computed tomography (CT) scan of the whole abdomen revealed a strip of soft tissue density shadow in the ileocecal region connected to the cecum. An enhancement scan showed slight ring enhancement in the arterial phase and slightly increased enhancement in the portal phase (Fig. 1, arrowheads), and multiple nodules with similar intensification were seen. Cystic solid mass shadows were observed in the bilateral adnexal areas, in which multiple strip dividers were visible, and the cyst wall and dividers were slightly strengthened (Fig. 2, arrowheads). It was considered an appendicitis malignant tumor with abdominal and bilateral adnexal metastasis. In the hepatobiliary surgery department of our hospital, colonoscopy biopsy samples revealed a few signet ring-like cells (Fig. 3, asterisk), and the immunohistochemical results were as follows: CK(+), CK7(-), CK20(-), Villin(+), CDX2(-), and CEA(+). The final diagnosis was signet-ring cell carcinoma of the appendix. Because of the large range of metastasis sites and high degree of malignancy of the tumor in the patient, she refused surgical treatment and proceeded with adjuvant chemotherapy after communication with the doctor. At a follow-up of 5 months after the start of chemotherapy, the patient underwent two enhanced CT scans. No significant changes were observed in the lesions of the appendix; however, the lesions of the bilateral ovaries were significantly enlarged, and intraperitoneal nodules and mass shadows increased and enlarged.