A Spectrum of Entities That May Mimic Abdominopelvic Abscesses Requiring Image-guided Drainage

A variety of entities may mimic drainable abscesses. This can lead to misdiagnosis of these entities, unnecessary percutaneous placement of a pigtail drainage catheter, other complications, and delay in appropriate treatment of the patient. Types of entities that may mimic drainable abscesses include neoplasms (lymphoma, gallbladder cancer, gastrointestinal stromal tumor, ovarian cancer, mesenteric fibromatosis, ruptured mature cystic teratoma, recurrent malignancy in a surgical bed), ischemia/infarction (liquefactive infarction of the spleen, infarcted splenule), diverticula (calyceal, Meckel, and giant colonic diverticula), and congenital variants (obstructed duplicated collecting system). Postoperative changes, including expected anatomy after urinary diversion or Roux-en-Y gastric bypass and small bowel resection, may also pose a diagnostic challenge. Nonpyogenic infections (Mycobacterium tuberculosis, Mycobacterium avium complex, echinococcal cysts) and inflammatory conditions such as xanthogranulomatous pyelonephritis and gossypiboma could also be misinterpreted as drainable fluid collections. Appropriate recognition of these entities is essential for optimal patient care. This article exposes radiologists to a variety of entities for which percutaneous drainage may be requested, but is not indicated, and highlights important imaging findings associated with these entities to facilitate greater diagnostic accuracy and treatment in their practice. ^©RSNA, 2018.