Endocrine Abstracts

Introduction: PTEN Hamartoma Tumor Syndrome (PHTS)is a rare genetic spectrum of disorders characterised by multiple hamartomas and increased risk of cancers including thyroid cancer. People with PHTS have an increased lifetime risk of differentiated thyroid carcinoma (DTC), estimated to be about 35% compared to the general population risk of below 1% (1).

Case Presentation: We report a 38-year-old male who presented with a Goitre found on routine examination present for over 2 years. Noticeably, he had unexplained mild learning difficulties and macrocephaly present since childhood. There were no risk factors for thyroid cancer on the first assessment. His thyroid function tests were normal, thyroid ultrasound USS showed a multinodular goitre with a U3 nodule and his fine needle aspiration FNA cytology was in keeping with non-neoplastic Thy2. He was also investigated for new rectal bleeding and found to have multiple bowel polyps on colonoscopy. He underwent diagnostic PTEN genetic testing and was found to have a pathogenic mosaic gene change in the PTEN gene, confirming new diagnosis of PHTS. Given the significant risk of a malignant transformation, he was discussed in the thyroid multidisciplinary team (MDT) meeting, discussing the rationale of prophylaxis thyroidectomy. A previous study favours the rationale of prophylactic thyroidectomy in certain patients with PHTS, particularly in those with developmental delay or who may struggle to adhere to screening guidelines (2). However, another study showed that patients who did not undergo a thyroidectomy also did not develop thyroid cancer during a 10-year follow-up (1). Following MDT decision, our patient underwent a prophylactic total thyroidectomy to reduce his anxiety and avoid the need for ongoing surveillance with USS & FNA.

Conclusion: It is always important to consider hereditary conditions like PHTS when evaluating patients with thyroid nodules. The need for further evaluation despite a non-neoplastic ultrasonographic and cytologic findings has to be guided based on the risk factors for thyroid cancer. Patients with PHTS are at a significantly increased risk of developing DTC and should undergo regular surveillance with consideration of prophylactic total thyroidectomy following MDT discussion.

References: 1. Szabo Yamashita T, Baky FJ, McKenzie TJ, Thompson GB, Farley DR, Lyden ML, Dy BM. Occurrence and Natural History of Thyroid Cancer in Patients with Cowden Syndrome. Eur Thyroid J. 2020 Sep;9(5):243-246. doi: 10.1159/000506422. Epub 2020 Mar 12. PMID: 33088792; PMCID: PMC7548836. 2. Milas M, Mester J, Metzger R, Shin J, Mitchell J, Berber E, Siperstein AE, Eng C. Should patients with Cowden syndrome undergo prophylactic thyroidectomy? Surgery. 2012 Dec;152(6):1201-10. doi: 10.1016/j.surg.2012.08.055. PMID: 2315818.