Cushing's disease after surgical resection and radiation therapy for nonfunctioning pituitary adenoma.

OBJECTIVE: To describe a patient with an aggressive nonfunctioning pituitary adenoma in whom Cushing's disease developed after two resections of tumor and radiation therapy.

METHODS: We present a case report, with serial laboratory and immunohistochemical data, and summarize information about similar patients described in the medical literature.

RESULTS: A 48-year-old woman had irregular menstrual periods, decreased peripheral vision, headaches, and weight gain. Laboratory and radiologic investigation revealed a large nonfunctioning pituitary adenoma. Transsphenoidal subtotal resection of the tumor improved her vision. Results of immunohistochemical studies were positive for b-follicle-stimulating hormone and b-luteinizing hormone. She had radiation therapy 1 year postoperatively for rapidly enlarging residual tumor. Bifrontal craniotomy was done 3 months later because of worsening vision. The pituitary adenoma from the second surgical procedure stained negatively for all pituitary hormones. Postoperatively, she received tapering doses of prednisone for 4 months. Two months after the last dose of prednisone, she had signs and symptoms of hypercortisolism. Inferior petrosal sinus venous sampling studies for plasma corticotropin confirmed the presence of Cushing's disease. She did not tolerate medical therapy. Bilateral adrenalectomy led to remission of hypercortisolism.

CONCLUSION: Nonfunctioning pituitary tumors often come to clinical attention when they are large and cause symptoms associated with hypopituitarism or invasion of parasellar structures. In contrast, functioning pituitary tumors may have few compressive symptoms if they manifest with complaints attributable to excessive pituitary hormones.