Malakoplakia Mimicking Metastatic Colon Cancer

Document Type

Conference Proceeding

Publication Date

10-1-2024

Publication Title

Am J Gastroenterol

Abstract

Introduction: Malakoplakia is a rare, chronic granulomatous inflammatory disease that results from impaired histiocyte clearance of bacteria in immune compromised individuals. We present a case of a postlung transplant patient that was suspected to have diffuse colonic metastatic disease based on computed tomography (computed tomography)that was later deemed to be diffuse malakoplakia related to systemic infection. Case Description/Methods: A 62-year-old woman with history of lung transplant on tacrolimus presented with abdominal distension and diarrhea. Vital signs were stable on arrival. Laboratory results including a complete blood count, liver and chemistry panels were noncontributory. Blood cultures repetitively grew Achromobacter xylosoxidans despite escalation of antibiotic therapy. Abdominal and pelvic computed tomography demonstrated gastric distension, and a colonic filling defect at the hepatic flexure with extensive adenopathy evading the duodenal serosa. At this time there were concerns of metastatic colon cancer with concomitant systemic infection. Interventional radiology performed lymph node biopsy revealing malakoplakia and negative for malignancy. Multidisciplinary discussion between infectious disease and gastroenterology was performed with concerns for the colonic filling defect as the origin of patient's persistent bacteremia. Colonoscopy was performed showing diffuse nodularity with ulcerations encompassing the right colon without a targetable lesion for source control. Biopsies were obtained redemonstrating malakoplakia. The patient's hospital course was complicated by COVID-19 pneumonia and ultimately expiring due to respiratory failure. Discussion: Malakoplakia is a poorly understood and rare chronic granulomatous inflammatory disease that results from bactericidal defect of histiocytes. This manifests in an accumulation of phagolysosomes most commonly in immune compromised individuals. Symptoms are non-specific ranging from asymptomatic to altered bowel habits, abdominal pain, rectal bleeding, and intestinal obstruction. Endoscopic appearance can range from flat lesions to multiple ulcerated polypoid nodules. Thus, as in this case, the diagnosis can often be delayed and result in unnecessary interventions until a true diagnosis is achieved. Once diagnosed antibiotic therapy is tailored to the culprit organism resulting an accumulation within histiocytes and killing the bacteria. This case serves to educate the reader of this rare disease presentation to limit extensive work up and expedite treatment (see Figure 1).

Volume

119

Issue

10

First Page

S1934

Last Page

S1934

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