Endocrine Abstracts

Background: Primary hyperparathyroidism (PHPT) and concomitant medullary thyroid disease is well described in literature as part of multiple endocrine neoplasia. However, coexistence of PHPT and papillary thyroid cancer (PTC) has only been scarcely documented in sporadic case reports and some surgical series.

We present two unusual cases of PHPT associated with synchronous multifocal PTC.

Cases: A 62-year-old woman with sporadic PHPT was noted to have a parathyroid adenoma by 99Tc-Sestamibi. She underwent parathyroidectomy with removal of three parathyroid glands at neck exploration, two of which were hyperplastic. Incidentally, she was found to have metastatic follicular variant of papillary thyroid carcinoma on histology in a cervical lymph node. Further imaging showed no other metastases. She then proceeded with completion thyroidectomy with lymph node clearance followed by radioactive iodine treatment.

A 68-year-old man was referred with incidental hypercalcaemia and biochemical PHPT. 99Tc-Sestamibi scan revealed a solitary parathyroid adenoma as well as incidental left-sided cervical adenopathy. Neck ultrasound also identified a 3.6×2.1 cm enlarged left cervical lymph node and noted a contralateral 2×1.7 cm irregular thyroid nodule. Fine needle aspiration (FNA) of the thyroid lesion was insignificant. This prompted FNA of the neck node which showed metastatic papillary thyroid carcinoma. He underwent a total thyroidectomy and cervical dissection with excision of the right parathyroid adenoma. Histology confirmed PTC with capsular infiltration.

Discussion: The mechanisms underlying the association between PHPT and PTC are not established. Recent studies favour the combined use of CT–SPECT and cervical ultrasound in the first instance, coupled with FNA of suspicious lesions. These cases underline the need for a high index of suspicion for synchronous hyperparathyroidism and non-medullary thyroid cancer. Co-existence of both disease processes may complicate patient management via unrecognised thyroid cancer and the necessity for re-operative neck surgery.