Case Report: An Encapsulated Mass of the Gluteal Region Found During Cadaveric Dissection

Abstract

We describe a large, encapsulated mass containing friable tissue – likely a partially healed hematoma or abscess – in the right gluteal region of a 93-year-old female cadaver, which potentially caused impaired function of the ipsilateral tensor fasciae latae. We first observed this mass between the right gluteus medius and gluteus minimus muscles during dissection lab for the Physical Therapy DPT students. This structure was roughly circular (~11 cm in maximum width) and completely encapsulated by dense connective tissue. Since the inferior aspect appeared to pass through the sciatic foramen, we hypothesized that this was caused by a sciatic hernia. However, this was rejected based on the later dissection of the abdominal and pelvic cavities. None of the structures that can potentially cause a sciatic hernia – colon, ovaries, uterine tube, ureter – were protruding through the sciatic foramen. Additionally, dissection of the gluteal region revealed that the dense connective tissue covering the mass was not passing through the sciatic foramen, rather it was adhered to the ilium near the greater sciatic notch. Dissection of the structure itself showed that its margins were limited to the borders of the gluteus medius and it was composed of two layers of dense connective tissue with clear fluid between them. The outer layer of connective tissue had the appearance of thickened intermuscular fascia. Within the second layer, completely encapsulated, was friable tissue. This suite of characteristics is consistent with a partially healed intermuscular hematoma or abscess, but the pathologic diagnoses of this mass cannot be confirmed without histologic evaluation. Intermuscular hematomas and abscesses in the gluteal region can be caused by traumatic damage to the superior gluteal artery, trigger point injections, and hip arthroplasty. A plausible side effect of this mass lesion is compromised function of the superior gluteal nerve and artery. The tensor fasciae latae on the right side was 9.6% shorter and 13.4% lower in mass than on the left side. There was symmetry and no evidence of degeneration to the gluteus medius and gluteus minimus muscles, so it is possible that there was only a disruption to the innervation or blood supply to the ipsilateral tensor fasciae latae.