Brown tumor causing pathologic fracture of the ipsilateral femur and pelvis in a pregnant woman: a case report.

We present the case of a 30-year-old pregnant woman who was found to have an aggressive-appearing osteolytic lesion of the left distal femur in the setting of hypercalcemia. Biopsy confirmed a brown tumor secondary to hyperparathyroidism. She underwent a successful parathyroidectomy followed by a Cesarean section. Postpartum, she sustained pathologic fractures of the ipsilateral femur and pelvis due to a fall, requiring operative fixation. She progressed to uncomplicated healing following surgical management. Although brown tumors can appear aggressive on imaging, they typically resolve following treatment of the underlying hyperparathyroidism. Pathologic fractures should be managed according to standard orthopedic principles. Clinicians should include brown tumors in the differential diagnosis when evaluating osteolytic lesions, particularly in the presence of hypercalcemia.