Gastric Metastasis of Anaplastic Thyroid Carcinoma: A Case Report.

Background/Aims Most common site of metastasis for anaplastic thyroid carcinoma (ATC) is lungs, liver and regional lymph nodes. Gastrointestinal metastasis is unusual. We report a case who presented ATC accompanied with gastric, lung and pancreas metastases. Methods A 64-year-old female with hypertension presented with palpable neck mass and hoarseness. Fine needle aspiration revealed ATC. At that time, she had upper gastroscopy from outside medical center which detected 7-mm-sized EGC at antrum, posterior wall and biopsy was proven as signet ring cell cancer. She underwent endoscopic submucosal dissection (ESD) from our medical center and histopathologic result was large cell carcinoma with rhabdoid phenotype. Chest computed tomography (CT) and abdomen CT, positron emission tomography-CT were done and about 3.6-cm-sized pancreas metastatic cancer and metastatic lung nodules, Lt. para-aortic lymph node metastasis were detected. Results Our initial diagnosis was anaplastic thyroid cancer with lung and pancreas metastasis and early gastric cancer (double primary cancer). But second histopathologic revision of ESD tissue was done and Pax-8 resulted as positive, so the final diagnosis was ATC multiple metastasis. Conclusions Stomach is rare site of ATC metastasis, and metastatic lesions to the stomach are often difficult to distinguish from that of primary gastric cancer. This case could be the useful reference for similar cases. [ABSTRACT FROM AUTHOR]