Endocrine Abstracts

History and examination: A 46-year-old gentleman presented with right sided goitre which had increased in size over one month. He previously had a left thyroidectomy for non-toxic goitre.

As a child he had several lipomas removed. On examination he has mucosal neuromas, an AV malformation on his left wrist, white papules on his hands and trichilemmonas on his legs. He has macroencephalopathy, 64.4 cm round. The right lobe of the thyroid was enlarged and he was clinically euthyroid.

His child had a large head and Asperger like features further to which he was referred for genetic testing. A pTEN mutation was shown, and further testing showed the patient to have the same mutation. A diagnosis of Cowden syndrome was made.

Investigation: His FT₄ 12.9 pmol/l and TSH 1.25 mU/l and thyroid peroxidase antibodies 13 IU/ml.

Thyroid ultrasound revealed enlarged right lobe with multiple nodules, predominantly solid with some calcification. The dominant nodule was biopsed and the results showed follicular variant of papillary carcinoma.

Discussion: Cowdens syndrome is a rare condition caused by a mutation of the pTEN gene on the 10q23. It is autosomal dominant inheritance with variable expression and is associated with thyroid cancer. The protein pTEN encodes for the phosphatase and tensin homolog which acts as a tumour suppressor gene. Mutations of pTEN cause uncontrolled cell growth leading to hamartoma formation. While it affects both sexes equally, there is an increased mortality associated with malignant tumours of the breast in women and of the thyroid in men.

When dealing with thyroid abnormalities in patients with macroencephalopathy and dermatological lesions, it is important to consider Cowdens syndrome. It is associated with increased thyroid abnormalities which include goitre, benign adenomas, thyroglossal cysts and follicular adenocarcinomas. We will discuss Cowden syndrome in more detail and its association with thyroid cancer.