Session: MON 167-198-Hypothalamus-Pituitary Development & Biology
Poster Board MON-187
A 26 year old man was seen in Endocrine clinic for sweats and tremors. At 7 years of age he had left testicular growth and resection demonstrated a Leydig cell tumor. He was diagnosed with Carney complex (CNC) on the basis of the testicular lesion and the family history of CNC in his mother and sister, with cardiac atrial myxomas.
Physical Examination: Ht 6 ft. 2 inch, Wt 251 lbs , BP 129/68 mmHg , Pulse 78 per minute. He appeared to be a rugged, tall, muscular man. Pertinent physical findings included no acral or mandibular enlargement and normal visual fields.
IGF1 level was elevated 732ng/ml, glucose tolerance test showed inadequate GH (2.5 ng/ml) suppression. MRI showed a microadenoma and transsphenoidal surgery performed. IGF1 levels declined to a nadir 309 ng/ml, but rose over the next two years to 417ng/ml.
Our patient had two major criteria of CNC, testicular lesion and acromegaly and one supplemental criteria, family history. CNC is one of the few hereditary pituitary tumors. It is most commonly caused by mutation of Protein kinase A R1alpha regulatory subunit (PKAR1A) gene located on chromosome 17q 22-24 which functions as a tumor suppressor gene. Protein Kinase A (PKA) has four subunits and is a cAMP dependent enzyme. cAMP stimulates PKA by binding to two regulatory subunits, releasing the catalytic units for phosphorylation of proteins. Deficiency of R1 alpha regulatory subunit results in PKA over activity leading to cell proliferation. Most of the symptoms in CNC are related to unregulated cell proliferation. Pituitary tumors in both CNC and McCune Albright Syndrome (MAS) are preferentially associated with acromegaly. MAS is caused by GNAS gene mutations. It results in a G protein that causes adenylate cyclase enzyme to be activated leading to similarities with CNC.
Both CNC and MAS, may have acromegaly from either hyperplasia or pituitary adenomas. We suspect that our patient had both hyperplasia and a pituitary adenoma since resection of the adenoma has not corrected the GH excess. We are starting somatostatin analog to normalize excess GH secretion and IGF-1 and possibly prevent future development of pituitary tumors. Somatostatin analogs have been shown to be effective in the treatment of sporadic acromegaly as well as in MAS. We have been unable to identify reports of using somatostatin analogs for CNC.
Nothing to Disclose: NNT, ALB
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