Co-occurrence of Functional Gonadotroph Adenoma and Lactotroph Adenoma: A Case Report and Literature Review

Abstract

Background/objective: Functional gonadotroph adenomas (FGAs) are adenomas producing active gonadotropins, follicle-stimulating hormone or luteinizing hormone. Double pituitary adenomas are 2 distinct adenomas occurring in an individual. This report aimed to present an extremely rare case of an FGA, itself an uncommon disorder, co-occurring with a lactotroph adenoma.

Case report: A 33-year-old woman presented with menorrhagia and was found to have ovarian enlargement, large uterine leiomyomas, and bitemporal hemianopsia. Initially, the levels of follicle-stimulating hormone, luteinizing hormone, estradiol, and prolactin were 73.3 mIU/mL (midcycle peak, 2.3-20.9 mIU/L), 3.74 mIU/L (midcycle peak, 8.7-76.3 mIU/L), 1071 pg/mL (midcycle peak 38-649 pg/mL), and 402 ng/mL (2-30 ng/mL), respectively. Pituitary magnetic resonance imaging demonstrated a single sellar mass (2.0 × 2.2 cm). Two months of cabergoline did not reverse visual field deficits; therefore, transsphenoidal resection was performed. Diagnosis of 2 separate adenomas, a gonadotroph and lactotroph adenoma, was confirmed on pathology.

Discussion: In this case, gonadotropins did not suppress in response to hyperprolactinemia. Although marked hyperprolactinemia has been associated with functional and clinically silent gonadotroph adenomas in prior cases, this is the first case to confirm an FGA co-occurring with a lactotroph adenoma.

Conclusion: In patients who present with elevated gonadotropin levels despite hyperprolactinemia, we suggest considering FGA. Further research is needed to clarify whether there is underdiagnosis of lactotroph adenomas co-occurring with gonadotroph adenomas.

Keywords: ACTH, adrenocorticotropic hormone; ASU, α-subunit; FGA, functional gonadotroph adenoma; FSH, follicle-stimulating hormone; IHC, immunohistochemistry; LH, luteinizing hormone; MRI, magnetic resonance imaging; PRL, prolactin; TSH, thyroid-stimulating hormone; double adenoma; functional gonadotroph adenoma; lactotroph adenoma; prolactinoma.

Fig. 1

Preoperative and postoperative pituitary magnetic resonance imaging (MRI). Preoperative postcontrast T1 sagittal (A) and T2 coronal (B) pituitary MRI demonstrating a 2.1 × 2.0 × 2.2-cm sellar mass with suprasellar extension compressing the optic chiasm without evidence of cavernous sinus invasion. Postoperative T1 coronal (C) and T1 sagittal (D) MRI showing no definitive mass residual or recurrence.

Fig. 2

Histopathology of the pituitary adenomas. Two separate adenomas were present on the surgical specimen that were separated by tongues of compressed pituitary gland (A, hematoxylin and eosin; B, Wilder reticulin). The larger tumor was composed of medium-sized cells with eosinophilic to clear cytoplasm and central nuclei with homogeneous chromatin pattern (C). The tumor cells expressed SF1 (E) and β-follicle-stimulating hormone (G). The tumor was also immunoreactive for β-luteinizing hormone and α-subunit of glycoproteins (not shown). The second adenoma was composed of smaller eosinophilic cells with central hyperchromatic nuclei (D). The tumor cells expressed PIT1 (F) and prolactin (H). (A, C, D) Hematoxylin and eosin. (B) Wilder reticulin (B). (C-F) Immunohistochemistry for SF1 (E), PTI1 (F), β-follicle-stimulating hormone (G), and prolactin (H). Original magnifications: ×10 (A, B, E, F) and ×40 (C, D, G, H).