Malakoplakia of the colon associated with colonic adenocarcinoma diagnosed in colonic biopsies.

Malakoplakia, typically involving the urinary tract, is an uncommon form of chronic inflammation caused by chronic infections and characterized by accumulation of macrophages. It has also been found in many other sites such as the gastrointestinal tract, pancreas, liver, lymph nodes, skin, respiratory tract, adrenal gland, vagina and brain. We present a case of a 64-year-old man referred to our hospital with cachexia and radiologic evidence of metastatic tumor of the liver. Colonoscopy revealed a large malignant - appearing polypoid mass of the ascending colon and multiple distinct polyps throughout the rest of the colon. Biopsies of the ascending colon mass confirmed the diagnosis of adenocarcinoma. Histological examination of two of the other polyps revealed malakoplakia which was characterized by aggregates of granular histiocytes with Michaelis - Gutmann bodies and histochemically confirmed with periodic acid-Schiff and von Kossa stains. This is a rare case diagnosed on endoscopic samples. The majority of reported cases were found in surgical specimens. In addition, the endoscopic appearance of multiple polyps is unusual in malakoplakia.