-Case Reports-

Chronic Expanding Hematoma Extending over Multiple Gluteal Muscles Associated with Piriformis Syndrome

Yasuyuki Kitagawa¹, Munehiro Yokoyama², Kensuke Tamai¹ and Shinro Takai³

¹Department of Orthopaedic Surgery, Nippon Medical School Tama Nagayama Hospital
²Department of Pathology, Tokyo Metropolitan Police Hospital
³Department of Orthopaedic Surgery, Nippon Medical School

We report on a patient with an unusual, slowly enlarging hematoma of the left buttock. A 62-year-old man presented with a 6-year history of an enlarging mass of the left buttock. He had first noted the mass 6 years earlier and had had sciatica of the left lower limb for the last 2 months. He denied any history of antecedent trauma. The lesion extended over 3 gluteal muscles (the gluteus medius, gluteus minimus, and piriformis). On microscopic examination, the lesion showed typical signs of chronic expanding hematoma. The sciatica was relieved after surgical removal of the lesion. The lesion had not recurred at the last follow-up 4 years after the operation. The present case suggested that chronic expanding hematoma can extend into multiple muscles due, perhaps, to long-term growth and the anatomical and functional conditions of the affected muscles. Our case also suggests that chronic expanding hematoma can be a cause of piriformis syndrome.

J Nippon Med Sch 2012; 79: 478-483

Keywords
hematoma, gluteal, piriformis syndrome

Correspondence to
Yasuyuki Kitagawa, MD, Department of Orthopaedic Surgery, Nippon Medical School Tama Nagayama Hospital, 1-7-1 Nagayama, Tama, Tokyo 206-8512, Japan
kitayasu@nms.ac.jp

Received, January 24, 2012
Accepted, March 21, 2012