ERBB2 and signet ring cell gastric adenocarcinoma: In the meantime, after a neurosurgery consultation, the patient was proposed for a biopsy of the causa equina, which showed metastatic spread of a signet ring cell gastric adenocarcinoma c-erb2/NEU 2+ (antibody c-ErbB2 DAKO); negative fluorescence in situ hybridization (FISH) was utilized.