Iliopsoas Abscess Possibly due to Klebsiella pneumoniae Infection after Chemoradiotherapy for Hypopharyngeal Cancer.

Iliopsoas abscess was once an uncommon condition but now occurs somewhat more frequently due to the increasing number of immunocompromised patients, such as those with diabetes. We encountered a case of iliopsoas abscess following chemoradiotherapy for hypopharyngeal cancer. A 60-year-old man was admitted for a sore throat and left neck swelling. Hypopharyngeal cancer was diagnosed, but the patient refused surgery. After two rounds of chemotherapy, febrile neutropenia developed and chest computed tomography (CT) revealed an iliopsoas abscess. The platelet count was low but recovered after administration of antibiotics and could not be explained by puncture of the abscess. CT-guided drainage eventually improved his symptoms. Even for disorders of the head and neck region, iliopsoas abscess should be suspected in immunocompromised patients who develop a fever. CT and magnetic resonance imaging should be performed at an early stage as it is important to determine whether surgical drainage is indicated.