Sclerosing mucoepidermoid carcinoma with eosinophilia of the thyroid: report of two patients, one with distant metastasis, and review of the literature.

Sclerosing mucoepidermoid carcinoma with eosinophilia (SMECE) is a recently recognized malignant neoplasm of the thyroid gland. Two additional cases of this condition which occurred in a 70-year-old woman and a 69-year-old woman are presented. The case of the 70-year-old woman (patient 1) is the first report of distant metastasis, besides lymph node metastasis, for this type of tumor. The patient initially presented with a thyroid mass, and the thyroid gland with surrounding cervical lymph nodes was removed. Because of focal keratin "pearl" formation, the tumor was misinterpreted as a metastatic squamous cell carcinoma to the thyroid. Approximately 4 years later, the patient developed a left supraclavicular mass and lung densities. A pathological fracture of the right humeral head followed, and the left supraclavicular mass recurred along with newly developed subcutaneous nodules on the chest wall and arm. Open lung and bone biopsies revealed metastatic SMECE, which was morphologically identical to that of the thyroid mass. The 69-year-old woman (patient 2) had, in 1983, undergone thyroidectomy with left radical neck dissection; this had been diagnosed as follicular carcinoma of the thyroid with lymph node involvement. After multiple isolated lymph nodes metastases, the patient developed locally extensive, recurrent tumor that showed microscopic features of SMECE. Review of the previous thyroid tumor and lymph nodes revealed the same type of histology. To our knowledge, only a single report containing eight cases of this distinctive carcinoma of the thyroid has been published. Herein we describe characteristic morphological features of two additional cases of this rare malignancy, one with distant metastasis, and we review the related literature.