Esophageal Adenocarcinoma Metastasizing to a Solitary Fibrous Tumor: An Unprecedented Case of Tumor-to-tumor Metastasis.

BACKGROUND Tumor-to-tumor (TMT) metastasis is a rare phenomenon in which a primary malignancy undergoes metastasis to an additional synchronous or metachronous primary tumor. CASE REPORT This is a case report of a tumor-to-tumor metastasis from a poorly differentiated adenocarcinoma of the esophagus to a solitary fibrous tumor (SFT) of the right posterior neck, in a 70-year-old-male with a solitary right vertebral artery. After appropriate work-up and involvement of the necessary specialties, the patient underwent a complex surgical resection with negative margins. CONCLUSION We present the unique case of a patient with TMT from esophageal adenocarcinoma to an SFT in the posterior neck, not previously reported in the literature. This rare condition with unique oncologic implications highlights the need for a multidisciplinary approach, in this case involving thoracic surgery, head-and-neck surgery, medical oncology, radiation oncology, pathology, and neurosurgical sub-specialty services.