Hydatid cyst of the thyroid gland: report of three cases.

Cystic Echinococcosis is a parasitic infestation that is distributed world-wide. It may be found in nearly any part of the body, most often in the liver and the lungs, but occasionally in other structures such as the thyroid gland. The present study reports three cases of hydatid cysts of the thyroid gland, in patient ranging from 18 to 25 years of age. Two patients had concomitant hydatid disease involving organs other than the thyroid gland (secondary disease), and one had, sole, involvement of the thyroid gland itself (primary disease). Moreover, an occult papillary thyroid carcinoma was detected incidentally in one case, involving the unilateral thyroid lobe as the hydatid cyst. While several surgical procedures including left lobectomy and isthmectomy were undertaken in one patient, two patients underwent total thyroidectomy. No disease recurrence was observed in any of the three patients during the postoperative follow-up period. No study reporting the concomitance of hydatid cyst and neoplasia of the thyroid gland has been previously published. This concomitance indicates the importance of the differential diagnosis of lesions characterized by calcifications in the thyroid gland, especially in endemic regions.