Endocrine Abstracts

Parathyroid carcinoma (PTC) is a rare condition that lacks pathognomonic features, making diagnosis and therefore management challenging. In the very few cases of intra-thyroidal PTC reported, failure to achieve a pre-operative diagnosis has often led to unnecessary bilateral neck exploration and re-operation. We describe for the first time a case of intra-thyroidal PTC suspected pre-operatively. A 37-year-old Bangladeshi man presented with a 3-week history of mood changes, muscle and bone pain, fatigue and thirst. He had a biochemical picture consistent with primary hyperparathyroidism with raised serum calcium (3.23 mmol/L), low phosphate (0.39 mmol/L), raised parathyroid hormone (31.3 pmol/L), low vitamin D3 (31 nmol/L) and raised urinary calcium (14.7 mmol/day). His thyroid function was normal. His hypercalcaemia was refractory to medical management. Interestingly, an ultrasound scan revealed a suspicious solid nodule within the right lobe of the thyroid with malignant features including irregular borders, hypoechogenicity and micro-calcifications. Fine needle aspiration revealed groups of follicular cells and a pseudopapillary architecture with bare nuclei. The suspicious nodule showed prominent tracer uptake and subsequent delayed washout on a sestamibi parathyroid scan and reduced activity on a thyroid isotope scan. PTC was suspected pre-operatively. An elective right hemi-thyroidectomy, isthmectomy and ipsilateral parathyroidectomy were performed. Intra-operatively the mass was adherent to the strap muscles as well as the trachea. Frozen sections revealed an intrathyroidal parathyroid. Formal histological analysis confirmed parathyroid carcinoma infiltrating into the thyroid gland. The case raised concerns of a malignancy located within the thyroid gland. However, initially there was uncertainty whether this was solely a PTC or a thyroid carcinoma with concomitant unidentified parathyroid pathology. Intrathyroidal PTC, although exceptionally rare, was suspected because of the significantly high serum calcium co-existing with suspicious ultrasound features in conjunction with corresponding localisation on radioisotope scans. The accurate diagnosis led to a minimally invasive and potentially curative procedure without any complications.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.