Growth hormone-producing pituitary adenoma regrowing as pituitary adenoma with neuronal choristoma 14 years after tumor removal.

Background: We report a case of an uncommon association of pituitary adenoma with neuronal choristoma that usually is diagnosed at initial surgery.

Case Description: A 50-year-old woman with acromegaly and bitemporal hemianopsia underwent removal of a pituitary adenoma via the transsphenoidal approach. Histologic examination of the first surgical specimen demonstrated only adenoma, which was eosinophilic and expressed growth hormone. Fourteen years later, bitemporal hemianopsia recurred, and magnetic resonance imaging revealed regrowth of the residual tumor.

Discussion: The patient underwent removal of the regrown tumor via the transsphenoidal approach. Histologic examination of the second surgical specimen revealed gangliocytoma and a small component of pituitary adenoma.

Conclusions: The present case report supports the theory that pituitary adenoma with neuronal choristoma might represent the result of neuronal differentiation from pituitary adenoma.