8385 Coexistence of Parathyroid Adenoma & Papillary Thyroid Cancer: A Rare Case Report
Authors: Dash Kalpana , Verma Shivendra , Ayyagari Usha , Roy Mou , Rathore Smriti 
Published: October 2024

Abstract
Disclosure: K. Dash: None. S. Verma: None. U. Ayyagari: None. M. Roy: None. S. Rathore: None.
Prevalence of primary hyperparathyroidism (pHPT) ranges from 0.1- 0.4% in general population. Nodular thyroid disease is an increasingly common incidental diagnosis due to widespread use of ultrasound. Papillary thyroid cancer (PTC) is the most common cancer of thyroid gland. Here we report a 53 year old post-menopausal woman presented with weight loss, generalised body aches, arthralgia, myalgia, and proximal muscle weakness. She was hypertensive and clinically euthyroid. Physical examination revealed generalized tenderness all over the body but no thyroid or parathyroid nodules on palpation. Biochemical evaluation showed hypercalcemia 12.1mg/dl (8.4-10.2mg/dl), PTH&gt;2000pg/ml (14-72pg/ml), ALP-1855 U/L (40–125 U/L), decreased phosphorous of 2.4mg/dl (25-4.6 mg/dl), and vitamin-D of 46 nmol/L ( 75-250 nmol/L). USG neck revealed a heterogeneous lesion at the lower pole of right lobe of thyroid gland & two small hypoechoic nodules seen in the right lobe of thyroid gland. FNAC from nodules was inconclusive. USG abdomen revealed nephrocalcinosis. DEXA scan showed severe osteoporosis. Tc99mSestamibi SPECT-CT showed uptake at lower pole of right lobe of thyroid. On exploration, two nodules were palpated in the right lobe of the thyroid and simultaneous right hemi-thyroidectomy was performed. Histopathologic report confirmed parathyroid adenoma (figure 1) as well as presence of carcinoma in the two nodules: one was a papillary thyroid cancer (Classic variant) and the other a follicular variant of papillary thyroid carcinoma (figure 2). Margins were negative for malignancy. She was treated with levothyroxine to maintain TSH &lt;0.1U/L and followed up with annual ultrasound screening. At 2 year follow up, patient was symptom free with improved T score on DEXA scan and no nodule over residual thyroid gland. Discussion: Co-existence of pHPT and PTC ranges from 2.3-4.3%. The use of ultrasound neck as a routine imaging modality for localisation of parathyroid adenoma allows detection of thyroid nodules. Benign and/or malignant thyroid nodules are commonly seen in patients with pHPT and this can range from 2-15%. Women have higher risk for co-existence. The relationship between the two diseases is thought to be incidental. Some authors have suggested possible role of shared genes, embryological factors, transcription factors, vitamin-D deficiency and hyperparathyroidism that could lead to activation of angiogenic factors and carcinogenesis. Fig. 1. Parathyroid adenoma. (a)Tc99m sestamibi scan showing right inferior parathyroid adenoma (b) Parathyroid adenoma (400x high power) comprising predominantly of Chief cells with mild pleomorphism. Fig. 2. Histopathology of PTC. (a)Papillary Carcinoma thyroid. 10xPhotomicrograph showing areas of calcification. (b) Papillary Carcinoma thyroid. Photomicrograph showing thyroid with papillary pattern with areas of infiltration.
Presentation: 6/1/2024