Benign calcified thyroid cyst with skin sinus formation

OBJECTIVES: To present a rare case of calcified thyroid cyst with discharging neck sinus and its probable explanation. MATERIALS AND METHODS: A 75-year-old male patient presented to the outpatients department who had had thyroid swelling for the last 50 years and a discharging neck sinus from the swelling with ulceration and fungation of the adjoining area for the last year. RESULTS: An X-ray of the soft tissue of the neck showed tracheal shift to the right and irregular calcification of the left lobe of the thyroid. Fine needle aspiration cytology (FNAC) of the left lobe yielded little material with inflammatory cells as the swelling was too hard to be easily penetrated with a needle. FNAC of the right lobe revealed a picture similar to adenomatous goiter. A subtotal thyroidectomy was performed and the histopathologic report was suggestive of multinodular goiter with dystrophic calcification. CONCLUSION: Though the clinical features of the patient mimicked malignant change in a pre-existing adenomatoid goiter, histopathologically, it was found to be a calcified thyroid cyst. Probable explanation is given in the "Discussion" section.