Cushing's disease due to mixed pituitary adenoma-gangliocytoma of the posterior pituitary gland presenting with Aspergillus sp. sinus infection

Gangliocytic lesions of the pituitary gland producing Cushing's disease are extremely rare entities that may exist with or without a pituitary adenoma. The latter have been designated mixed pituitary adenoma-gangliocytomas, the majority of which produce growth hormone, not adreno-corticotropin (ACTH), and are localized to the anterior gland. We now report an immunocompetent woman with hypercortisolism who presented with an intranasal aspergilloma eroding the bony sellar floor. The fungal ball was contiguous with, and extended into, a large neurohypophyseal-centered mass. Transsphenoidal resection revealed a gangliocytic lesion of the posterior gland with small clusters of intimately admixed ACTH-immunoreactive adenoma cells as the cause of her Cushing's disease. Rare transitional sizes and shapes of cells coupled with immunohistochemical findings supported interpretation as advanced neuronal metaplasia within an ACTH adenoma. This mixed ACTH adenoma-gangliocytoma is the first example to present clinically with an opportunistic infection.