Abstract
BACKGROUND: The primary lymphomas of mucosa associated lymphoid tissue (MALT) of the gallbladder (GB) is an extremely rare of non-Hodgkin lymphoma. Many patients exhibit symptoms like gallstone disease, and in some cases, the lymphoma may be detected through imaging even without apparent symptoms. Only 19 cases of primary MALT lymphoma in the GB have been previously reported. Differential diagnosis from typical GB carcinoma based solely on imaging findings can be challenging, and definitive diagnosis often requires surgical intervention. CASE SUMMARY: We present a patient in an 82-year-old man who was initially diagnosed with prostate cancer but incidentally detected GB wall thickening from magnetic resonance imaging conducted for prostatic surgery and subsequent radical cholecystectomy revealed primary MALT lymphoma of the GB. The patient was followed up by a medical oncologist, and after discussion, the decision was made to continue observation with close monitoring without systemic chemotherapy given the asymptomatic presentation. The patient has been free of recurrence for 16 months after the surgery. Although precise diagnosis before the surgery was difficult in this case, preoperative examinations revealed a submucosal tumor-like lesion. CONCLUSION: MALT lymphoma of GB remains little known in many previous studies. It is really difficult to preoperatively diagnose. The combination of clinical presentation, postoperative histology and immunohistochemistry contribute to diagnosis and carry out appropriate management.