We report the use of a genetic test for therapeutic decision making in a case of primary hyperparathyroidism associated with Cushing's disease (CD). A 20-year-old woman was evaluated for gradual weight gain, asthenia, muscle pain, and hypertension. Biochemical and radiologic tests confirmed CD and she underwent transsphenoidal surgery. Immunohistochemistry of the microadenoma was positive for adrenocorticotropic hormone (ACTH). On follow-up, hypercalcemia with high parathyroid hormone (PTH) levels was detected, associated with nephrolithiasis and low bone mineral density in the spine and hip. Parathyroid scintigraphy showed tracer uptake in the inferior region of the left thyroid lobe, and cervical ultrasound showed a heterogeneous nodule in the same area, suggestive of a parathyroid adenoma (PA). Genetic testing detected mutation in the MEN 1 gene and total parathyroidectomy with the implantation of a fragment of one gland in the forearm was performed. Pathology showed a PA and 3 normal parathyroid glands, without hyperplasia, despite the diagnosis of MEN 1. This case illustrates the role of genetic testing in defining the therapeutic approach for sporadic MEN 1.
