Amyloid Deposition Within a Large Pelvic Chronic Expanding Hematoma

Abstract

Abstract Introduction/Objective Chronic expanding hematoma (CEH) is a relatively rare complication of trauma that is usually mistaken for a soft tissue neoplasm. The identification of amyloid protein is of paramount clinical importance to exclude serious conditions causing systemic amyloidosis. Methods The case was retrieved from the pathology files at the University of Miami Hospital (UMH). Morphology and special stains were reviewed. The study was approved by the Institutional Review Board at UMH. Results A 44-year-old man with past history of a stab wound in the left buttock in the 1990s, was admitted with worsening abdominal pain, constipation, urinary obstruction and acute kidney injury. CT-scan showed a large mass involving the left gluteal area and pelvic cavity involving urinary bladder causing outlet obstruction and bilateral hydroureteronephrosis. Multiple radiology-guided biopsies were taken all identifying only fibrin, blood cells, and necrotic inflammatory cells. Excision of the gluteal mass and drainage of the pelvic component was performed confirming the diagnosis of CEH. Amyloid deposition with congo red stain birefringence under polarized light was identified. The patient’s symptoms and renal function improved and have been under follow-up for 1 month. Conclusion We have identified amyloid protein deposition whiting a CEH. This is an unusual finding with no previous description found in our search. The identification of amyloid whiting tumor-like lesions is relevant to exclude causes of systemic amyloidosis.