2677 A Rare Case of Primary Signet Ring Cell Bladder Adenocarcinoma With Metastases to the Stomach

Abstract

INTRODUCTION: Primary signet ring cell adenocarcinoma (SRCA) of the urinary bladder is a rare malignancy, accounting for about 0.24% of all bladder malignancies. Additionally, metastases to the stomach regardless of primary malignancy is also rare, with rates estimated to be between 0.2-0.7%. Here we are reporting a case of primary SRCA of the bladder with eventual metastases to the stomach. CASE DESCRIPTION/METHODS: A 65-year-old male with rheumatoid arthritis on chronic immunosuppression and history of T4N0M0 primary SRCA of the bladder status-post radical cystectomy was admitted with persistent nausea, vomiting and reduced oral intake leading to acute kidney injury. Symptoms were refractory to conservative measures so CT Abdomen was obtained which revealed distal esophageal wall thickening. Due to concern for infectious esophagitis given his chronic immune suppression, esophagogastroduodenoscopy (EGD) was performed. EGD revealed multiple nodules (5-10 mm) with central umbilication scattered within the gastric fundus and body. The lesions were biopsied and stains were consistent with signet ring cell adenocarcinoma positive for CX7, CX20, CDX-2; Beta-catenin was not performed. Bladder specimen from prior cystectomy was also positive for CX7, CX20, CDX-2, and predominately membranous staining for Beta-catenin. PET scan obtained after EGD was significant only for retroperitoneal lymphadenopathy thought to represent metastases. Previous workup at the time of initial bladder adenocarcinoma diagnosis including colonoscopy and imaging were all negative for additional foci of malignancy confirming primary bladder adenocarcinoma. Hence, it was concluded that the gastric lesions represented metastasis to the stomach from primary SRCA of urinary bladder. Due to underlying comorbidities and poor baseline functionality, patient elected to proceed with hospice care. DISCUSSION: Primary urinary bladder SRCA is a rare type of malignancy that typically presents at an advanced stage. Standard therapy of local urinary bladder SRCA is radical cystectomy. Despite advances in identifying immunohistochemical markers which aid in determination of primary bladder vs. colorectal origin, rates of metastases after surgical intervention are uncertain which limits the discussion regarding the role of adjuvant therapy. Our case highlights the need for further investigation to evaluate the risk-benefit ratio of adjuvant chemotherapy after radical cystectomy in primary bladder SRCA in minimizing development of future distant metastases.