Spindle epithelial tumor with thymus-like differentiation of the thyroid (SETTLE): Report of two cases (one associated with a parathyroid adenoma).

Spindle epithelial tumor with thymus-like differentiation (SETTLE) is a rare tumor usually localized in the thyroid gland and perithyroid tissues. It is considered to arise from ectopic thymic tissue or branchial pouch remnants. It occurs more frequently in children and adolescents. We report 2 cases of spindle epithelial tumor with thymus-like differentiation localized in the thyroid gland, and 1 of them was associated with a parathyroid adenoma. We emphasize the need for a close and long-term follow-up in these patients.