A case of follicular thyroid carcinoma associated with phosphatase and tensin homologue hamartoma tumour syndrome

Abstract

A 15-year-old boy was referred to our department with a complaint of neck mass noted by his mother a year ago. He did not have changes in weight, appetite and energy level; constipation; diarrhoea; or a sensation of feeling cold or hot. The patient did not report difficulty swallowing or breathing. He had undergone surgical treatment for vascular malformations involving both legs 3 years ago. He lived with his mother and 24-year-old sister, and both of them were healthy. His father died in a road traffic accident at age 35. There was no family history of thyroid disease. On examination, the patient was slim and appeared well. His temperature was 36.9 C, with a pulse of 90 beats per minute, the respiratory rate 18 breaths per minute and blood pressure 100/60 mmHg. His weight was 45.8 kg (fourth percentile), height 164.6 cm (21st percentile) and body mass index of 16.9 (fourth percentile). The thyroid was enlarged with well-defined and firm masses in both thyroid lobes; the largest one measured approximately 3.5 cm in the right lobe. There was no exophthalmos, lid lag or enlarged cervical lymph nodes. The remainder of the physical examination was normal, and pubertal development was consistent at Tanner stage 4. There were surgical incision scars along his legs. Blood levels of free thyroxine and thyrotropin were normal, and testing for thyroid peroxidase and thyroglobulin antibodies was negative. The ultrasonography examination of thyroid showed a multinodular goitre with a dominant 2.9 cm right-sided nodule. The cytopathology of fine-needle aspiration biopsy of the dominant thyroid nodule was categorised as suspicious for follicular neoplasm. Total thyroidectomy demonstrated a right-sided follicular carcinoma and bilateral multiple adenomatous nodules. The combination of follicular thyroid carcinoma (FTC) and requirement of surgery for vascular malformation brought to mind the possibility of a diagnosis of Cowden syndrome/phosphatase and tensin homologue hamartoma tumour syndrome (CS/PHTS). On re-examination, we noted macrocephaly and macular pigmentation of the glans penis (Fig. 1). Head circumference was 60.5 cm (>97th percentile). Colonoscopy demonstrated the presence of numerous colorectal polyps (Fig. 2). Based on these findings, the patient was diagnosed with CS/PTHS. Mutation analysis of the PTEN gene was performed, which documented a mutation (p.R335*) in the gene. This mutation was previously associated with CS/PTHS.