Fellow Guthrie/Robert Packer Hospital Sayre, Pennsylvania, United States
Introduction : The hypothalamic-hypophyseal-pituitary (HHP) axis is a crucial regulatory hub within the endocrine system, managing hormonal signals for maintaining homeostasis in the body. From the paraventricular, arcuate, & supraoptic nucleus to the anterior & posterior pituitary, lesions affecting any part of this path can cause a variety of endocrine disorders. Hypopituitarism when it occurs, can involve hormone deficiencies of both the anterior & posterior pituitary depending on the location affected within the HHP.
Case(s) Description : Here, we present a 40-year-old male with well controlled DM1 & stage I melanoma who had wide excision surgery earlier in the year with clear margins. He complained ofprogressive polyuria and polydipsia along with significant fatigue and low libidoover the last6 months despite well-controlled DM1. Biochemical work-up was significant with very low free & total testosterone, low FSH & LH, mildly elevated prolactin, increased serum osmolality, and dilute urine. ACTH, morning cortisol, DHEA-S, TFTs were all normal. A 12-hour water deprivation test confirmed central DI with low copeptin. He was started on desmopressin with improvement in polydipsia/polyuria and also started on topical testosterone.MRI brain w/wo contrast showed disseminated nodular pial enhancement involving the brainstem, cerebellum, hypothalamus, pituitary stalk, & inferior aspect of the brain possibly suggestive of neuro-sarcoidosis, leptomeningeal carcinomatosis, neurocutaneous melanosis, or fungal/TB infection. Lumbar puncture showed normal glucose; normal CSF ACE level; increased lymphocytes, high protein & IgG (no oligoclonal bands), high albumin. Cultures and gram stain were negative. Interestingly, review of a lymph node biopsy done during resection of his melanoma showed sarcoid like granulomas. CT chest abdomen/pelvis with IV contrast revealed mediastinal & bilateral hilar lymphadenopathy along with numerous bilateral subcentimeter pulmonary nodules of varying size. Subsequent bronchoscopy with biopsy of pulmonary noduleswas negative for any malignancy. Awhole body PET scan demonstrated mildly calcified and FDG avid lymphoid tissue involving the nasopharynx, cervical, mediastinal, perihilar, mesenteric, and pelvic sidewall.Currently,the differential diagnosis includes melanoma stage IV with CNS involvement or neuro-sarcoidosis. CNS biopsy is scheduled to be done in a few weeks.
Discussion : Presentation of hypopituitarism in younger patients could be subtle and requires a high degree of suspicion. In addition,a multi-specialty approach is necessary when complex structural pathology and variable endocrine abnormalities are being managed as in this case which involved collaboration of his PCP, endocrinology, hospitalist, pulmonology, oncology, interventional radiology, and neurology.
.jpg "Vivek Kothari, MD (he/him/his) photo")