Gastric cancer metastatic to neck lipoma: a case report with imaging consideration

A 71-year-old man visited our hospital for examination of a soft neck mass. Computed tomography and magnetic resonance imaging scans showed a well-circumscribed large lipomatous tumor with multiple nodules inside. Atypical lipomatous tumor or lipoma involving the lymph nodes was considered. Pathological examination of the surgical specimen suggested typical lipoma including multiple metastatic foci from gastric cancer. Subsequent endoscopy revealed a gastric tumor, which was histologically proven to be signet-ring cell carcinoma. Considering these findings, this case was diagnosed as tumor-to-tumor metastasis to lipoma. We present the first such case with imaging and clinical characteristics.