Colonic Malakoplakia With an Adenomatous Appearance on Magnification Endoscopy: A Case Report

Area of Science:

• Gastroenterology
• Pathology
• Medical Imaging

Background:

• Malakoplakia is a rare chronic granulomatous disease impacting macrophage function.
• Colonic malakoplakia presents with diverse endoscopic findings, complicating differentiation from colorectal neoplasms.
• Impaired macrophage phagocytosis is a key characteristic of malakoplakia.

Purpose of the Study:

• To report a case of colonic malakoplakia with adenomatous features.
• To evaluate the utility of magnifying narrow-band imaging (NBI) in diagnosing colonic malakoplakia.
• To discuss the diagnostic challenges in differentiating colonic malakoplakia from colorectal neoplasms.

Main Methods:

• A patient with immunoglobulin A nephropathy on hemodialysis and corticosteroids underwent colonoscopy.
• Two polyps in the ascending colon were examined using magnifying narrow-band imaging (NBI).
• Lesions were resected via cold snare polypectomy and analyzed histopathologically.

Main Results:

• Magnifying NBI revealed varied surface patterns and vascular structures, with some areas resembling adenomatous changes.
• Endoscopic differentiation from malignancy was inconclusive.
• Histopathology confirmed malakoplakia, identifying Michaelis-Gutmann bodies within histiocytes.

Conclusions:

• Colonic malakoplakia can exhibit features mimicking adenomatous changes, posing diagnostic difficulties during endoscopy.
• Magnifying NBI provides detailed visualization but may not yield a definitive diagnosis.
• Histopathological examination remains crucial for the definitive diagnosis of colonic malakoplakia.