Endocrine Abstracts

Introduction: Multiple pituitary adenomas (PA) have a prevalence of 0.2-2.6% of all resected PAs. However, most of them are simultaneously diagnosed and in the setting of acromegaly. In a 2019 surgical series with 22 cases of multiple PAs, only one case was asynchronous and all of them had a positive immunohistochemical staining.

Case report: A 32-year-old woman (1996) was referred to na Endocrinology appointment with amenorrhea and weight gain for the last 6 months and recent diagnosed hypertension. Central obesity, moon facies, hirsutism and violaceous abdominal striae were present at physical examination. The initial evaluation revealed serum cortisol 28 mg/dl (6.24-18), ACTH 151 pg/ml (9-50) and urinary free cortisol (UFC) 3 times the upper limit of normal. No suppression was found after 2 and 8mg dexamethasone tests and the CRH test was negative. Pituitary MRI showed a left inferolateral microadenoma (8 mm) and the inferior petrosal sinus sampling confirmed the ACTH gradient. After transsphenoidal surgery, histology confirmed the diagnosis of Cushing’s disease. UFC levels normalized and the patient needed hydrocortisone for a year. The 6-month post operation MRI showed no evidence of residual lesions. Tem years later (2006), a follow up MRI described a median PA with 8x9x10mm, protruding to the suprasellar cistern. The patient reported symptoms of new weight gain and easy bruising. UFC levels were persistently elevated with no suppression in the 2 mg dexamethasone test, but serum ACTH was normal with a peak <50% in the CRH test. However, by this time, the patient was taking antiepileptic drugs. With the suspicion of recurrent Cushing’s disease, a second transsphenoidal surgery was performed. Histology revealed a null cell adenoma with negative immunostaining. Fifteen years later (2015), the residual lesion increased in size with 21×14×12 mm and invasion of the left cavernous sinus. With no evidence of hypercortisolism, she underwent fractionated stereotaxic radiotherapy. The most recent blood work showed normal pituitary function and the last MRI (2021) described a residual lesion with 9.7×3.5×4 mm.

Conclusion: Double PAs are a very rare entity that can pose a significant challenge. Detailed hormonal assessment and immunohistochemical staining are essential for correct diagnosis. This case illustrates a rare diagnosis of a corticotroph and a null cell adenoma. However, molecular analysis is currently in charge of providing a more accurate characterization of the last PA.