Abdominal actinomycosis misconceived as intestinal lymphoma: Report of a case

Abstract

Introduction: Abdominal actinomycosis is a rare clinical entity and it is difficult to make the correct preoperative diagnosis because of its nonspecific clinical symptoms and varied radiological findings. The diagnosis is usually made after the patient undergoes an operation and tissue is available for pathological evaluation. When the diagnosis is made, the patient should be treated with the appropriate long-term antibiotics.

Presentation of case: A 69-year-old male patient was transferred to our hospital complaining of a palpable mass, painful abdominal discomfort, weight loss, and night sweating. After colonoscopy and radiologic studies, our presumptive diagnosis was intestinal lymphoma combined with ileocecal intussusception. He was found to have abdominal actinomycosis after surgery and successfully treated with ampicillin for six months.

Discussion: Pre-operative radiological imaging in abdominal actinomycosis is unlikely to allow a definitive diagnosis, but CT scanning is the single most useful imaging modality. Although we performed preoperative radiological studies, including CT, none led to a diagnosis of abdominal actinomycosis, we mistakenly considered the case as intestinal lymphoma combined with ileocecal intussusception.

Conclusion: Physicians should include abdominal actinomycosis in the differential diagnosis when an abdominal mass presents an irregular, infiltrative growth pattern, even though ileocecal intussusception is an extremely rare presentation in abdominal actinomycosis.

Keywords: Actinomycosis; Intussusception; Lymphoma.

Fig. 1

a. Ultrasonograms show intact mucosa and thickened submucosal layer with short segment intussusception (arrow) of the terminal ileum. b. Contrast enhanced CT scans represent homogeneous mural attenuation with mild pericolic infiltration. Note the short intussusception of terminal ileum. c. Colon contrast study: Short intussuscepted segment (arrow) of the terminal ileum was visualized in the cecum. Terminal ileum shows relatively intact mucosa (arrow head) and thickened fold. d. Colonoscopy shows a prominent protrusion of ileocecal valve.

Fig. 2

a. Gross finding of resected specimen. b. The section of the cecal wall shows a single, eosinophilic granule within abscess cavity (hematoxylin & eosin stain; ×40). c. The section of abscess cavity shows an amphophilic sulfur granule ensheathed by eosinophilic, serrate material (hematoxylin & eosin stain; ×100).