A Rare Case Of Primary Gallbladder Maltoma Masquerading As Cholecystitis

INTRODUCTION: Mucosa-associated lymphoid tissue (MALTOMA), a marginal zone lymphoma, is a low-grade B cell non-Hodgkin’s lymphoma. It is the third most common non-Hodgkin’s lymphoma and commonly involves the stomach, lung, thyroid, and salivary glands. It’s occurrence in the gallbladder as a primary site is very rare. We present a unique case of a symptomatic patient who was diagnosed to have a possible cholecystitis with wall thickening on CT scan that was proven to be MALTOMA following endoscopicultrasound (EUS)-guided biopsy. CASE DESCRIPTION/METHODS: 78-year-old female with a PMH of hypothyroidism and GERD, presented with abdominal pain of 2 weeksduration. The patient underwent CT scan, which showed cholecystitis with gallbladder wall thickening (Figure 1), and elevated liver enzymes. EUS was performed for evaluation of elevated LFTs and showed diffuse gallbladder wall thickening measuring 8 mm (Figure 2). EUS-guided biopsy of the gall bladder wall showed low grade marginal zone B-cell lymphoma. Patient subsequently underwent cholecystectomy withsurgical pathology confirming the diagnosis of MALTOMA (Figure 3), with negative margins; and a negative post-operative PET scan on surveillance. DISCUSSION: Malignant lymphoma constitutes about 0.1–0.2% of gall bladder malignancies and about 40% ofmalignant lymphomas. The possible mechanism of MALTOMA in the gall bladder was thought to be due to lymphocytic infiltration secondary to chronic inflammation from infection or cholelithiasis and thesynthesis of fusion protein AP12 MALT1 from antigenic stimulation. As reported in our case, MALTOMA is commonly reported in females and often presents with abdominal pain, nausea, and vomiting. The radiological findings of MALTOMA have varied between cases in the literature, either as wall thickening ,a mass, a polypoid lesion, or a submucosal tumor. In the present case, focal wall thickening andinflammation was seen, which is more suggestive of cholecystitis. Given such scenarios, it is importantto keep MALTOMA on the differential. Surgery is the most common treatment in localized gall bladder lymphoma and carries an excellent prognosis. The recurrence rate after treatment for MALTOMA was reported as 37%, so it very important to perform frequent surveillance.Figure 1.: CT scan showed cholecystitis with gall bladder wall thickening (shown by arrow).Figure 2.: 2A: Gall bladder wall thickening measuring 8 mm (shown by arrow), 2B: Fine needle aspiration of the gall bladder (shown by arrow).Figure 3.: Lymphocytic proliferation in the gall bladder mucosa.