[A case of psoas abscess due to renal pelvic carcinoma complicated with non-ketotic hyperosmolar diabetic coma]

A 85-year-old man was admitted to our hospital because of semicomatous status. Laboratory data on admission showed elevation of blood sugar (823 mg/dl) and serum osmotic pressure (345 mOsm/l), but ketonuria was not detected. Non-ketotic hyperosmolar diabetic coma was diagnosed. The insulin infusion and physiological saline improved the blood sugar level and consciousness within a day. The abdominal ultrasound examination revealed an abscess in the left kidney and right psoas muscle. The same findings were seen by abdominal computed tomography but the possibility of malignant neoplasm of the left kidney could not be ruled out because of a swelling of the left adrenal gland. Pain associated with psoas abscess and low grade fever were observed. Because of his poor general condition, drainage of the abscess was not performed and conservative therapy using antibiotics was administered. Without any improvement of the abscess, he died due to general deterioration four months later. Autopsy findings showed carcinoma of the left renal pelvis and metastasis to the right psoas muscle, left adrenal gland, liver, bilateral lungs and lymph modes. Psoas abscess is a relatively uncommon disease, especially in elderly patients. The etiology of the disease is divided into primary and secondary causes. Most secondary psoas abscess cases are caused by intestinal diseases, and Crohn's disease has been related to the highest incidence. A few cases of psoas abscess caused by colorectal carcinoma have been reported. Ultrasound and computed tomography are useful in diagnosing this disease and drainage of an abscess is necessary for therapy and proving the cause. Cancer metastasis should considered in differential diagnoses, when psoas abscess is seen in elderly patients.