The Usefulness of CytoFoam-Core in the Diagnosis of Thyroid Metastasis From Colon Cancer: A Case Report

Introduction: We report a case of a 64-year old man with a history of colon carcinoma. He underwent fine-needle aspiration by CytoFoam-core and diagnosis of metastatic colon cancer to the thyroid gland. Case presentation: In this case report, a solid thyroid nodule in the right lobe of a 64-year-old male was aspirated. The cytological smears showed a small group of atypical cells with the obvious nucleolus, necrosis, and atypical tall columnar cells. Since the patient had undergone surgery for rectal cancer at age 63, suspicion of metastasis from colon cancer was raised. This was corroborated by CytoFoam-core immunocytochemistry; showing a positive staining pattern for caudal type homeobox transcription factor 2 (cd×2) and cytokeratin 20 (CK20); while thyroglobulin (TG) and thyroid transcription factor-1 (TTF-1) were both negative. Conclusion: The main objective was to correctly identify the metastatic thyroid carcinoma (MTC) and exclude other clinical entities as primary diseases of the thyroid gland. Cytology plays a crucial role in the follow-up and the therapeutic management of the patients. The CytoFoam-core preparations were diagnostic of metastatic colon cancer to the thyroid gland. In this context, the CytoFoam-core could be of great help, especially in previous oncologic history cases.