Pleurihormonal Pituitary Adenomas Presenting as Acromegaly

Abstract

Abstract Background: Pleurihormonal pituitary adenomas represent 10-15% of all functioning pituitary adenomas1. One of the rarest combinations is ACTH-GH co-secretion with concomitant acromegaly and Cushing’s disease. Clinical Case: 30-year-old female with type 2 diabetes (A1c 11.4%) developed rapidly progressive peripheral neuropathy. Labs revealed a transaminitis. Hepatic ultrasound revealed fatty infiltration of the liver consistent with steatosis. Patient endorsed life-long “chicken legs”, buffalo hump, and easy bruising. She continued to have worsening paresthesias and stated her teeth were “more translucent”. At an endocrinology visit peripheral muscle wasting, atraumatic bruising at the ankles and toes,and striae on the abdomen, shoulders, breasts, and armpits were noted. She had also noted teeth separation and thinning over time and worsening diffuse joint aches. Lab results showed elevated cortisol value of 8.4 mcg/dl after 1 mg dexamethasone suppression test. 24-hour urine cortisol was elevated (87 ug/24 hrs, nl < 45 ug/24 hrs), confirming the diagnosis of Cushing’s syndrome. ACTH was inappropriately normal (56 pg/mL, nl 7.2 – 63 pg/mL), suggesting ACTH dependency. IGF-1 was elevated twice (328 ng/dL and 391 ng/dL, nl <303 ng/dL), and a GH suppression test was abnormal (GH 1.14 ng/mL at 90 minutes) confirming the diagnosis of acromegaly. Brain MRI revealed a cystic pituitary microadenoma (0.5 x 0.5 x 0.6 cm), and the patient underwent surgical resection via transnasal transsphenoidal pituitary surgery with total tumor removal. Immunostaining was positive for only synaptophysin and ACTH. Postoperative diagnosis of Cushing’s disease was made, with formal diagnosis of acromegaly pending improvement in follow-up IGF-1 levels. Literature reviews have revealed very few cases of pleurihormonal pituitary adenomas presenting with concomitant Cushing’s Syndrome and acromegaly. Roca et. al examined 17 studies which described 20 patients with this condition; only 4 presented with symptoms of both acromegaly and Cushing’s disease. In many cases previously reported, the clinical presentation of Cushing’s syndrome was subtle, often with subclinical Cushing’s syndrome, while patients had florid symptoms of acromegaly.1. Conclusion: This Cushing’s predominant case of a GH-ACTH co-secreting tumor is an incredibly rare presentation for this pleurihormonal pituitary adenoma, which is already a rare diagnosis. References: 1.Roca E, Mattogno PP, Porcelli T, Poliani L, Belotti F, Schreiber A, Maffezzoni F, Fontanella MM, Doglietto F. Plurihormonal ACTH-GH Pituitary Adenoma: Case Report and Systematic Literature Review. World Neurosurg. 2018 Jun;114:e158-e164. PMID: 29501516.