title: Acromegaly as a cause of 1,25-dihydroxyvitamin D-dependent hypercalcemia: case reports and review of the literature.
abstract: Growth hormone excess has been associated with hypercalciuria and nephrolithiasis. Hypercalcemia in acromegaly is rare and usually due to coexistent primary hyperparathyroidism. To report two cases of 1,25-dihydroxyvitamin D (1,25 (OH)(2) D)-dependent hypercalcemia in cromegaly. A 50 year-old female with 2 years history of hypercalcemia presented with features of acromegaly. Serum calcium (Ca) was 10.9 mg/dl (8.6-10.2), parathyroid hormone (PTH) 20 pg/ml (10-65), PTH-related peptide undetectable, and 1,25 (OH)(2) D 119 pg/ml (15-75). Insulin-like growth factor 1 (IGF1) was 911 ng/ml (49-292) and growth hormone (GH) 14.5 ng/ml (0.03-10). MRI showed a 1.7 cm pituitary tumor. Transsphenoidal adenectomy (TSA) resulted in normalization of IGF1, GH, Ca, and 1,25 (OH)(2) D (50 pg/ml) and complete tumor resection. A 52-year-old female was diagnosed with visual field deficits on routine exam. MRI showed a 3 cm invasive pituitary macroadenoma. IGF1 was 416 ng/ml (87-238) and GH 75.8 (0-6.0) ng/ml. Incidentally, she was found with high Ca of 10.8 mg/dl (8.9-10.3) associated with PTH 19 pg/ml and 1,25 (OH)(2) D66 pg/ml. Postoperatively, IGF1 and GH remained abnormal (440 and 12.8 ng/ml, respectively), while MRI showed parasellar tumor residue. Ca remained high (10.1-11.1 mg/dl), along with elevated 1,25 (OH)(2) D level (81.3 pg/ml). In both cases, other causes of hypercalcemia were ruled out. We present 2 cases of 1,25 (OH)(2) D-dependent hypercalcemia associated with growth hormone excess. Complete resection of tumor produced biochemical remission of acromegaly and normalization of calcium and 1,25 (OH)(2) D levels, while incomplete resection was associated with persistent 1,25 (OH)(2) D-dependent hypercalcemia. Acromegaly should be considered a cause of 1,25 (OH)(2) D-dependent hypercalcemia.
authors.affiliation: Division of Endocrinology, Diabetes and Lipids. Department of Medicine, Emory University School of Medicine, 1365 B Clifton Rd NE, Atlanta, GA 30329, USA.
authors.forename: Reshma
authors.initials: R
authors.lastname: Shah
authors.forename: Angelo
authors.initials: A
authors.lastname: Licata
authors.forename: Nelson M
authors.initials: NM
authors.lastname: Oyesiku
authors.forename: Adriana G
authors.initials: AG
authors.lastname: Ioachimescu
mesh_terms: D000172:Acromegaly / Q000150:complications*; D005260:Female; D019382:Human Growth Hormone / Q000378:metabolism; D006801:Humans; D006934:Hypercalcemia / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D019382:Human Growth Hormone; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; D007334:Insulin-Like Growth Factor I