Two cases of concurrent carcinoma showing thymus-like differentiation (CASTLE) coexisting with papillary thyroid carcinoma.

Carcinoma showing thymus-like differentiation (CASTLE), which emerges within the thyroid gland or the adjacent soft tissues of the neck, is a rare malignant neoplasm found globally. The occurrence of CASTLE in conjunction with papillary thyroid carcinoma is an even more infrequent phenomenon. The ensuing sections elaborate upon the clinical attributes characteristic of CASTLE.