Large Nonfunctioning Pituitary Adenoma Presenting with Visual Loss During Late Pregnancy—Challenges in Management

ABSTRACT

Nonfunctioning pituitary adenomas (NFPA) are very rare during pregnancy since fertility is usually impaired. A 31 year old hirsute woman was referred to the Endocrine Clinic for a large pituitary tumor, discovered at 35 weeks of gestation. She complained of increasing headache and abnormal vision, particularly in her left eye in the previous few weeks. An MRI scan showed a pituitary mass: 3.1 ×2.7 ×1.8 cm (LL/CC/AP) with suprasellar extension, and compression of the optic chiasm. Serum prolactin and the results of other endocrine investigations were normal, so she was diagnosed with NFPA. Both inducing labour or medication (bromocriptine) administration while proceeding to a safe term for pregnancy were considered. However, we chose to only follow her closely. There was no further deterioration and, at 38 weeks, a caesarian section was performed and a healthy boy was delivered. Two weeks after delivery, she underwent craniotomy (by right lateral subfrontal approach) with resection of the NFPA, followed by complete regression of the visual disturbances. The postoperative MRI demonstrated empty sella and no residual tumor, while the hormonal evaluation detected no significant pituitary insufficiency. Although cost-effective, combined histologic and immunophenotypic studies, especially extended IHC tests, can reduce the incidence of misdiagnosed large-cell lymphoma. As exemplified in this present case, obtaining appropriate and sufficient tissue from the tumor could possibly increase the chance of finding an accurate diagnosis.