Endocrine Abstracts

Background: Parathyroid cancer (P?) in children is extremely rare, more often sporadic, but may be associated with a germline mutation. The only effective treatment is surgical approach due to the chemo-radio-resistance of PC.

Clinical case: A 6-years-old girl presented with weakness, gait disturbance, pain in the limbs, an X-shaped curvature of the legs. At the age of 12, the patient’s well-being worsened sharply. The laboratory examination revealed primary hyperparathyroidism (PHPT): PTH 208 pmol/l, phosphorus 0.8 mmol/l, calcium ionized 1.76 mmol/l, alkaline phosphatase 4779 U/l. Ultrasound (US) showed a nodule 29×17×17 mm near to the left lobe of the thyroid gland. At the age of 13, she underwent a selective parathyroidectomy with the achievement of remission. The histological structure was more consistent with a parathyroid adenoma (tumor structures in the lumen of some blood vessels were regarded as introduced during the preparation of the histological specimen). A germline heterozygous mutation c.70 G>T, p. Glu24Ter in exon 1 of the CDC73 was identified. At the age of 15 years, there was a relapse of PHPT: PTH 527 pg/ml, Ca++1.4 mmol/l, total calcium 3.05 mmol/l. US visualized an hypoechoic lesion 8×4×6 mm in the area of the removed PTG which accumulated ^99mTc-MIBI on scintigraphy with SPECT-CT. The tumor of the left upper PTG with adjacent tissue was removed. Pathology examination showed invasive growth of PC into skeletal muscles and loss of parafibromin expression. One year later the patient underwent left hemithyroidectomy with ipsilateral lymphadenectomy, partial excision of the muscles, tissue and fascia to another recurrence of PC. Because of the PHPT persistence, a total thyroidectomy with pretracheal lymphadenectomy and the removal of lymph nodes, soft tissue on the right was subsequently completed followed by supraclavicular lymphadenectomy on the right. US and ^99mTc-MIBI scintigraphy visualized an intramuscular neck lymph node (metastasis) 9×12×8 mm on the right accumulating the isotope. The ineffectiveness of the previous surgical treatment led to subsequent local radiotherapy (SOD 50 Gy) without remission achievement, however, in combination with cinacalcet 45 mg/day allowed to maintain mild hypercalcemia.

Conclusion: The bone deformities in childhood require calcium and PTH levels to be checked. If the diagnosis of PHPT is confirmed, a genetic study is necessary to exclude hereditary forms. A mutation in the CDC73 gene should be aware of an increased risk of PC.