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Ectopic Hormone Syndromes. Case 1. 65 y/o F presents with 20 lb weight loss over last 2 months, new onset hyperglycemia, HTN, and hypokalemia Pt is markedly hyperpigmented and cachectic. Chest X-ray. Ectopic Cushing’s Syndrome.
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Case 1 • 65 y/o F presents with 20 lb weight loss over last 2 months, new onset hyperglycemia, HTN, and hypokalemia • Pt is markedly hyperpigmented and cachectic
Ectopic Cushing’s Syndrome • Due to production of ACTH, or rarely CRH, from source other than pituitary/hypothalamus • 15% of all Cushing’s Syndrome • Tumors can be very aggressive and therefore pt’s present more like cancer than Cushing’s, or can be indolent tumors and present like Cushing’s • Tumors express POMC which is then processed to ACTH and MSH
Ectopic Cushing’s • Make diagnosis by documenting elevated cortisol levels: • 24 urine free cortisol • Low dose and high dose dex suppression • Inferior Petrosal Sinus Sampling • Can be hard to detect • Chest/Abd/Pelvis imaging • Octreotide scans
Treatment • If find tumor, surgically resect • If can’t find tumor or if tumor unresectable, can treat medically • Ketoconazole • Metyrapone • Ketamine • Aminoglutethamide • Mitotane
Case 2 • 68 y/o M presents w/ dehydration and mental status changes • Labs show Ca=16.5 mg/ dL
PTH Related Protein • A protein expressed in many cells whose main function is growth and differentiation • Occupies PTH receptor to carry out it’s functions • However, when make large amounts of it, acts like PTH to: • Increase osteoclast function • Increase conversion of 25 to 1,25 vitamin D leading to increased absorption of calcium through the gut • Increase renal resorption of calcium
Tumors that make PTH-rp • Renal Cell • Squamous cell • Bladder • Melanoma • Breast • Prostate
Treatment • Hydration • IV Bisphosphonates • Subq calcitonin • Treat underlying malignancy
Case 3 • A 25 y/o M presents with multiple stress fractures, bone pain, and muscle weakness • He had a tender mass at the right posterior 9th rib • Labs show Phosphate=0.8 mmol/dL • Normal calcium • Elevated alk phos
Oncogenic Osteomalacia • Also called Tumor Induced Osteomalacia • See renal phosphate wasting and vitamin D abnormalities • Get inappropriate phosphate renal wasting due to excess production of fibroblast growth factors (phosphotonins), most common is FGF 23 • FGFs inhibit phosphate reabsorption at the proximal tubule, and also inhibit 1 hydroxylation of 25 vit D
Oncogenic Osteomalacia • Tumors are usually benign and derived from bone or soft tissue • Can be very hard to find—look in mouth, sinuses, and extremities • Some reports that PET and octreotide scanning were able to localize the tumor • Treatment is resection of tumor, but if can’t find treat w/ phosphate replacement and calcitriol
Case 4 • 65 y/o M presents with hypoglycemia. No hx of DM and no access to DM meds. • CT scan looking for pancreatic mass finds a large retroperitoneal mass • Insulin levels are low
Non-islet Cell tumor • Usually bulky mesenchymal tumors • Fibrosarcomas • Rhabdomyosarcomas • Leiomyosarcomas • Mesotheliomas • hemangiopericytomas • Hepatomas, carcinoid tumors, and adrenocortical carcinomas account for 25% • See suppressed insulin, GH, and IGF binding proteins Make up 50%
Why hypoglycemia? • Tumors secrete increased amounts of IGF-II • There is altered binding increasing it’s bioavailability and effect • More IGF-II goes to insulin receptors in tissues leading to: • Increased clearance of glucose from circulation to muscle • Decreased hepatic gluconeogenesis • Suppression of lipolysis
Treatment • Treat underlying malignancy • GH, glucagon, glucocorticoids, or somatostatin have been effective in individual patients with unresectable tumors
Case 5 • An 81 y/o F presents w/ tachycardia, weight loss, tremors, and sweats. • TSH<0.01 • FT4=5.2 • Neck exam is unremarkable • Denies use of thyroid hormone
Imaging I131 scan of neck I131 scan of pelvis Pelvic CT
Struma Ovarii • An ovarian tumor containing thyroid tissue as the predominant cell type • Typically occur as part of a teratoma but may occasionally be encountered with serous or mucinous cystadenomas • Malignant transformation is rare • Most strumal tissue is not functionally active, and cases associated with thyrotoxicosis can be due to autoimmune stimulation of the normal thyroid gland
Struma Ovarii • Between 0.8-3% of teratomas contain functional thyroid tissue or thyroid tissue occupying most of the mass. They are thus classified as a struma ovarii. Approximately 15% of teratomas have a small, nonsignificant focus of thyroid tissue. • The fifth and sixth decades are the ages of peak frequency • Struma ovarii rarely occurs before puberty
Case 6 • A 25 y/o M presents with gynecomastia and symptoms of hyperthyroidism • Has slight goiter on exam • TSH<0.01, FT4-1.7
Germ Cell Tumor • Can secrete HCG which leads to excess production of testosterone and estrogen • Can also directly occupy TSH receptors causing hyperthyroidism similar to pregnancy • Important to measure HCG in all men w/ gynecomastia • Can also be secreted from hepatic, biliary, gastric, bladder, reanal, and pancreatic, but often not bioligically active