Intra thyroid thymic carcinoma: A case report and literature review.

INTRODUCTION AND IMPORTANCE: Intrathyroid thymic carcinoma (ITC) is a malignant epithelial tumor with thymic differentiation within the thyroid gland. Its frequency is up to 0.15 % of all malignant thyroid tumors. It is frequently a low-grade tumor. The clinical status is often misleading to other more advanced tumors like cervical lymph node metastasis of nonkeratinizing squamous cell carcinoma, undifferentiated variant, dedifferentiated carcinoma, and medullary carcinoma of the thyroid. CASE PREPARATION: The patient came to us with the diagnosis of cervical lymph node metastasis of undifferentiated carcinoma. This patient was first diagnosed with cervical lymph node metastasis in the previous hospital. After having an ITC diagnosis, the patient was operated on the rennet of thyroid glands and had a low dose of radio-chemotherapy for recurrent prevention purposes. It is the first case of such a disease diagnosed at our hospital and also the first case reported in Vietnam. CLINICAL DISCUSSION: ITC is rare and appears similar to all thymic carcinoma variants. The most popular type is squamous carcinoma. Immunohistochemical stains are typical for thymic origin tumors with CD5, CD117 positive. ITC is often negative for monoclonal PAX8 but positive in this case (MRQ-50 clone, Sigma-Aldrich). This finding is an exciting one that should considered. CONCLUSION: Reporting the case increases the awareness of the disease, especially among Vietnam Doctors and patients.