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Misleading localization by 18F-fluorocholine PET/CT in familial hypocalciuric hypercalcemia type-3: a case report
- Source :
- BMC Endocrine Disorders, BMC Endocrine Disorders, Vol 21, Iss 1, Pp 1-8 (2021)
- Publication Year :
- 2021
- Publisher :
- Springer Science and Business Media LLC, 2021.
-
Abstract
- Background Familial hypocalciuric hypercalcemia (FHH) is a heterogeneous autosomal-dominant disorder of calcium hemostasis that may be difficult to distinguish clinically from mild primary hyperparathyroidism. Loss-of-function mutations mainly involving Arg15 residue of the adaptor-related protein complex 2, sigma subunit 1 (AP2S1) cause a rarer, more recently recognized form of FHH, FFH type-3. Recently, 18F-fluorocholine positron emission tomography/computed tomography (FCH-PET/CT) showed superior sensitivity to conventional imaging in localizing parathyroid adenomas. We report a new FFH type-3 patient who underwent unnecessary parathyroidectomy in association with misleading FCH-PET/CT imaging. Case presentation A 29-year old woman was initially evaluated for parathyroid hormone (PTH)-dependent hypercalcemia in 2013. Medical history was positive only for chronic constipation and malaise with no personal or family history of hypercalcemia, kidney stones, or neck surgery. Over seven years, serum calcium level was 2.51–2.89 mmol/L with concomitant PTH level of 58.7–94.8 mmol/L. Serum phosphate levels were in the low/low normal range. Serum creatinine and magnesium levels were normal. 25-hydroxy vitamin D level was 13 nmol/L. 24-hour urine calcium level was 1.92 mmol/day but increased to 6.99 mmol/day after treatment with cholecalciferol 1000 IU daily. Bone mineral density and renal ultrasound were normal. Parathyroid ultrasound showed two hypoechoic nodules inferior to the left and right thyroid lobes; however, 99mtechnitium-sestamibi scans (2013, 2016, 2018) were negative. FCH-PET/CT (2019) showed focal uptake co-localizing with the nodule inferior to the left thyroid lobe. The patient underwent left inferior parathyroidectomy and pathology was consistent with parathyroid hyperplasia. However, postoperatively, serum calcium and PTH levels remained elevated and FCH-PET/CT and ultrasound showed persistence of the uptake/nodule. Whole exome sequencing showed Arg15Cys mutation in the AP2S1 gene characteristic of FHH type-3. Conclusions In this new case of FHH type-3, FCH-PET/CT failed to localize to the hyperplastic parathyroid glands and localized instead to apparently a lymph node. This, together with increased urinary calcium after vitamin D supplementation, led to unnecessary parathyroidectomy. Given the increasingly lower cost of genetic testing and the cost of follow up and unnecessary surgery, it may prudent to include genetic testing for FHH early on in patients with mild PTH-dependent hypercalcemia.
- Subjects :
- Adult
Parathyroidectomy
medicine.medical_specialty
Adaptor Protein Complex sigma Subunits
Primary hyperparathyroidism
Endocrinology, Diabetes and Metabolism
medicine.medical_treatment
18F-fluorocholine positron emission tomography/ computed tomography
Adaptor Protein Complex 2
Urology
Parathyroid hormone
Case Report
Kidney
lcsh:Diseases of the endocrine glands. Clinical endocrinology
Choline
030218 nuclear medicine & medical imaging
Parathyroid Glands
03 medical and health sciences
0302 clinical medicine
Bone Density
Positron Emission Tomography Computed Tomography
medicine
Humans
PET-CT
lcsh:RC648-665
Familial hypocalciuric hypercalcemia
business.industry
Thyroid
General Medicine
Hyperparathyroidism, Primary
medicine.disease
Urinary calcium
Treatment Outcome
medicine.anatomical_structure
Parathyroid Hormone
030220 oncology & carcinogenesis
Hypercalcemia
Calcium
Female
Kidney stones
False positive localization
Radiopharmaceuticals
business
Familial hypocalciuric hypercalcemia type-3
Subjects
Details
- ISSN :
- 14726823
- Volume :
- 21
- Database :
- OpenAIRE
- Journal :
- BMC Endocrine Disorders
- Accession number :
- edsair.doi.dedup.....543eba58ed0a1bdcb9349b641ec71d9e