Abstract #1413579: Rathke Cleft Cyst Unveiling Incidental Prolactin Producing Adenoma

Abstract

Rathke cleft cysts (RCCs) are benign sellar and or/suprasellar lesions that arise from remnants of Rathke's pouch. Pituitary hormonal dysfunction associated with RCCs most often present as hormonal deficiencies due to compression. However pituitary hyper-secretion may coexist with RCC challenging diagnosis and management. A 37-year-old female presented with worsening headache, bilateral blurry vision and pressure-like eye pain for two weeks. She denied any galactorrhea or irregular periods. Her medications included as-needed butalbital-acetaminophen-caffeine and alprazolam. CT Head without IV contrast revealed a pituitary lesion measuring 1.9 cm extending near the inferior margin of the optic chiasm. Subsequent MRI Pituitary with and without IV contrast revealed an enhancing sellar/suprasellar solid lesion measuring 1.6 x 2.7 x 1.9 cm with small hypoenhancing components associated with expansion of the sella, rightward infundibulum deviation, mass effect on the optic chiasm and left cavernous sinus invasion. Pituitary secretion workup revealed an elevated serum prolactin level of 50.4 ng/mL (range 4.8 - 23.3 ng/mL). Repeat prolactin level was 75.7 mg/ml. Dilution studies 1:10 and 1:100 revealed prolactin levels of 78.3 ng/mL and 75.9 ng/mL respectively; absence of hook effect. Her elevated prolactin was attributed to stalk effect given the large size of her sellar mass and relatively minimally elevated prolactin level. Serum Alpha Subunit, ILGF-1, TSH, FT4, LF, FSH, AM cortisol and ACTH level were all normal. She underwent endoscopic transsphenoidal pituitary mass resection with pathology results revealing prolactin producing adenoma and RCC. Immunostains were strongly positive for chromogranin A and prolactin while negative for FSH, ACTH, TSH, beta hCG, GH. Prolactin levels 11 days post-resection remained elevated at 50.7 ng/mL. She continued to have regular periods without galactorrhea. Additionally, she expressed desire to attain pregnancy. This case illustrates the presence of a secreting pituitary prolactinoma in the setting of an RCC. Whether these two entities share a common pathophysiology or simply co-exist is unknown. In one study of 33 surgically treated RCC at presentation, 60% had gonadotroph deficiency, 36% had ACTH deficiency, 36% had TSH deficiency, 18% had ADH deficiency and 31% had hyperprolactinemia (1). It is possible that the majority of this patient 's sellar mass was comprised of RCC as a much higher prolactin level would have been expect for the size of her mass. Interesting, her sellar mass exhibited enhancement which is uncharacteristic for RCC, classical described as cystic lesions without calcification or enhancement. Given that her post-resection prolactin level remained elevated and she desires pregnancy, she may require dopamine agonist therapy.