Make the Diagnosis–A 58 Year Old Male with Abdominal Pain

A 58-year-old male presents with abdominal pain and bloody diarrhea which had a gradual onset over the last 3 weeks. He has lost 8 pounds during this period of time. A cecal biopsy is performed, and a representative section is shown here. What is the most likely diagnosis?

Amoebiasis

Ascariasis

Candidiasis

Cryptosporidiosis

Giardiasis

The diagnosis in this case is amoebiasis. The most common cause of amebic enterocolitis is Entamoeba histolytica, an organism spread through ingestion of cysts in contaminated food or water. The trophozoite forms are round, and frequently show intracytoplasmic red cells.

Amoeba with intracytoplasmic red cells

Occasionally, the organisms invade other organs, such as the liver, lung, and heart. Most patients may be treated on an outpatient basis, unless there is severe colitis or extraintestinal disease.

The organisms frequently invade through the mucosa and into the submucosa, often with lateral extension.

“Flask-shaped” ulcer in amoebiasis

Occasionally, the organisms invade other organs, such as the liver, lung, and heart. Most patients may be treated on an outpatient basis, unless there is severe colitis or extraintestinal disease.

-Kristine Krafts, MD, is an Assistant Professor of Pathology at the University of Minnesota School of Medicine and School of Dentistry and the founder of the educational website Pathology Student.