Introduction: Squamous cell carcinoma (SCC) of the thyroid is rare and is diagnosed by exclusion. It is essential to identify whether it is a primary tumour or metastatic from the aerodigestive tract. We present a case of an incidental finding of thyroid SCC and subsequent management and complications.

Case report: A 52-year-old lady underwent a right retrosternal thyroidectomy due to compressive symptoms. Some thyroid tissue was left-in-situ due to adherence to the trachea and oesophagus. After the histological diagnosis of thyroid SCC was made, and other primary or secondary tumour excluded using MRI and PET/CT, total thyroidectomy, bilateral neck dissection, partial tracheal ring resection repaired with strap muscle flap and tracheostomy were carried out. A postoperative oesophago-cutaneous fistula was confirmed with a barium swallow and the oesophageal defect was repaired with a pedicled pectoralis major muscle flap. Subsequent tracheal invasion of thyroid SCC required intraluminal laser excision of tracheal tumour. Despite chemotherapy with cisplatin and radical radiotherapy, the disease continued to invade locally and the patient died within 7 months.

Discussion: Prognosis is poor with thyroid SCC, mean survival being less than 16 months. Radioactive iodine is not helpful as thyroid SCC does not take up iodine. Due to advanced and aggressive loco-regional disease at the time of presentation, treatment included total thyroidectomy, tumour debulking, bilateral neck dissection followed by radiotherapy.

Conclusion: Squamous cell carcinoma is a rare thyroid malignancy which has no iodine affinity. It is an aggressive tumour requiring multimodal treatment and invariably has a poor prognosis.

Conflict of interest: None declared.