Mucin-producing adenoma of the thyroid gland

The authors studied a case of mucin-producing adenoma of the thyroid gland. The tumor consisted almost entirely of signet-ring cells containing mucin, which was strongly positive with PAS, with and without diastase pre-treatment, and Alcian blue stain at pH 2.5. Immunoperoxidase staining for thyreoglobulin was clearly positive within the cytoplasm of signet-ring cells and also in the follicle material, which indicates that the tumor derived from follicular epithelium.