1334 Malakoplakia Mimicking Pancreatic Cancer

Abstract

INTRODUCTION: Malakoplakia is an indolent immune disorder of the urinary tract with isolated reports of skin, brain, and GI involvement. It may present as a mass, and is sometimes associated with malignancy. We report a patient on immunosuppression for heart transplantation who presented with a pancreatico-duodenal mass and biliary obstruction from malakoplakia. CASE DESCRIPTION/METHODS: A 67- year old heart transplant patient presented with fevers, malaise, leukocytosis and right upper quadrant pain. MRCP demonstrated a heterogeneously enhancing 10 cm pancreatic head mass. EUS with FNA for cytology, AFB, fungal, and aerobic/anaerobic cultures were obtained. Histology showed malakoplakia without malignancy. E.coli grew from one culture and was treated with ceftriaxone and metronidazole. He developed jaundice with worsening biliary and pancreatic duct obstruction and enlargement of the mass on repeat MRCP. ERCP showed a large periampullary ulcerated mass and distal common bile duct stricture. Histology, cultures, flow cytometry, and viral testing of the mass and brushings from the CBD showed histology consistent with malakoplakia. Cultures were positive for MAI complex, Candida guilliermondii, and staphylococcus epidermidis. Treatment with ampicillin-sulbactam, fluconazole, azithromycin, doxycycline, ethambutol, ganciclovir, and moxifloxacin resulted in clinical improvement and decreased size of the mass. Fluconazole, doxycycline and bethanechol as adjunctive therapy will be continued until imaging resolution of malacoplakia. DISCUSSION: Malakoplakia is a rare inflammatory reaction characterized by infiltration of large foamy macrophages, triggered by infections in immunosuppressed patients. While mostly found in the urogenital tract, the GI tract is the second most common site where malakoplakia may occur, and if mass forming may mimic malignancy. Antibiotics with intracellular penetration are required to treat the organisms that have been phagocytized by macrophages. In malakoplakia, decreased intracellular cyclic-guanosine monophosphate (cGMP) ratios alter microtubule function and decrease β-glucuronidase release, resulting in impaired phagolysosomal digestion. Bethanechol increases cGMP levels and ascorbic acid promotes phagosome bactericidal activity, theoretically resulting in more effective bacterial killing. This report highlights malakoplakia as a potential masquerade for pancreatic cancer, an important differential consideration in immunosuppressed patients.