title: Ectopic thymic parathyroid adenoma and vitamin D deficiency rickets: a 5-year-follow-up case report and review of literature.
abstract: Sixteen patients with primary hyperparathyroidism presenting as rickets have so far been reported in the English literature. However, no report of an ectopic thymic parathyroid adenoma presenting as rickets has been published. We report a 14-year-old Caucasian American, wheelchair-ridden male who presented with signs and symptoms suggestive of vitamin D deficiency rickets subsequently confirmed by laboratory and radiological findings. Following the intramuscular administration of 125,000 U ergocalciferol (vitamin D2), he developed hypercalcemia with persistently elevated parathyroid hormone (PTH) levels suggestive of primary hyperparathyroidism. Sestamibi scan demonstrated significant uptake in the superior chest, without uptake at the normal parathyroid glands location. Surgical exploration revealed normal parathyroid glands and a thymic mass, which was removed and confirmed by pathology to be a parathyroid adenoma. With subsequent oral ergocalciferol solution and calcium carbonate therapies, the patient's symptoms resolved, blood chemistries normalized, and radiological evidence of rickets significantly improved. To our knowledge, this is the first case of an ectopic thymic parathyroid adenoma in a patient presenting with rickets. Our patient demonstrates that hyperparathyroidism-induced hypercalcemia may be masked by severe vitamin D deficiency. Prolonged treatment with ergocalciferol after removal of the parathyroid adenoma was necessary to normalize iPTH and replenish vitamin D store.
authors.affiliation: The Center for Endocrinology, Diabetes and Metabolism, Department of Pediatrics, Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California, 4650 Sunset Boulevard MS #61, Los Angeles, CA 90027, USA. dpisit@chla.usc.edu
authors.forename: Pisit
authors.initials: P
authors.lastname: Pitukcheewanont
authors.forename: Nawaporn
authors.initials: N
authors.lastname: Numbenjapon
authors.forename: Gertrude
authors.initials: G
authors.lastname: Costin
mesh_terms: D000293:Adolescent; D002118:Calcium / Q000097:blood / Q000627:therapeutic use; D004872:Ergocalciferols / Q000097:blood / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010282:Parathyroid Neoplasms / Q000097:blood / Q000473:pathology* / Q000601:surgery; D011859:Radiography; D012279:Rickets / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy; D013997:Time Factors; D014808:Vitamin D Deficiency / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy
chemical_list: D004872:Ergocalciferols; D002118:Calcium