High-grade mucoepidermoid carcinoma in the thyroid gland with poor prognosis

Abstract

Mucoepidermoid carcinoma (MEC) is the most common malignant neoplasm of the salivary gland, but primary thyroid MEC has rarely been reported and usually has a good prognosis. Herein, I report a case of thyroidal MEC with a poor prognosis in an 82-year-old woman with an anterior neck mass. Ultrasonography and computed tomography revealed a thyroid mass. The patient initially underwent fine-needle aspiration, was diagnosed with malignancy, and underwent a right lobectomy. On gross examination, a 4.0×3.6×2.6 cm-sized ill-defined, unencapsulated, and infiltrative tan to whitish mass with necrosis was identified. Microscopically, epidermoid tumor cell nests or solid sheets were identified. Mucous cells that were positive for periodic acid–Schiff and mucicarmine stains were also identified within epidermoid cell nests. Frequent mitosis and necrosis were observed. Immunohistochemical staining for p40 and p63 was positive, and that for thyroid transcription factor-1 and paired box gene 8 was focally positive. According to the Armed Forces Institute of Pathology grading system for salivary gland MEC, the current case was classified as high-grade MEC. After surgery, the patient suffered from dyspnea due to a remnant neck mass that compressed and obstructed the trachea; therefore, the patient refused further treatment. Thyroidal MECs are considered low-grade with a favorable prognosis, but there are several reported cases of thyroidal MEC with poor prognosis. The current case is a rare presentation of high-grade thyroidal MEC with a poor prognosis.

Mucoepidermoid carcinoma of the pancreas: A case report and literature review

“…According to their morphological and cytological characteristics, MECs in salivary glands are divided into 3 levels: low, medium, and high differentiation. [5] MEC is currently classified using the Armed Forces Institute of Pathology (AFIP) histological classification, which is based on histopathological features including a composite score of cystic components, nerve invasion, necrosis, mitotic activity, and cytological pleomorphism. [12] The AFIP quantitative grading system was based on the sum of the scores for the 5 histopathological features.…”

“…MECs are classified as low-, intermediate-, or high-grade according to their histologic features in the salivary gland. [5] Based on diagnostic standards, the final pathological diagnosis was high-grade mucoepidermoid carcinoma.…”

Recurrence of Papillary Thyroid Carcinoma Associated with Mucoepidermoid Carcinoma: An Uncommon Case Report

“…She had no family history of thyroid carcinoma or exposure to radiation. Some publications suggest that MECs can arise from metaplastic dedifferentiation of papillary thyroid carcinoma, follicular thyroid carcinoma, or oncocytic carcinoma (5,6). Primary thyroid MEC is frequently found in PCT (7).…”