THYMIC CARCINOMA INVOLVING THE THYROID-GLAND - REPORT OF 2 CASES

Two new cases of thymic carcinoma involving the thyroid gland and mani festing as thyroid tumors are presented, One tumor occurred within the thyroid gland and the other totally involved the thyroid gland, Micro scopically they showed lobular architecture separated by fibrous bands and consisted of solid islands of squamoid to spindled epithelial cel ls with whorl formation resembling Hassall's corpuscle and variable am ounts of lymphocytes. The squamoid to spindled epithelial cells were p ositive for cytokeratin but negative for thyroglobulin and calcitonin and the majority of lymphocytes showed a T-cell phenotype. One of the two cases had been diagnosed initially as squamous cell carcinoma of t he thyroid, This type of thyroid carcinoma is relatively rare, but it should be differentiated from other types of thyroid carcinomas, espec ially squamous cell carcinoma, medullary carcinoma, or anaplastic carc inoma of the thyroid. Copyright (C) 1995 by W.B. Saunders Company