FDG-Negative Signet Ring Cell Cancer of the Stomach With FDG-Positive Skin Metastases

A 27-year-old male patient presented with skin nodules at different locations, dysphagia, and vomiting. On gastroscopy, mucosal lesions were found in various parts of the stomach. Biopsy of these gastric lesions showed a poorly differentiated adenocarcinoma of signet ring cell morphology. The patient was referred for FDG PET/CT scan for further staging. The primary tumor in the stomach showed no significant FDG uptake, whereas the multiple skin nodules were FDG-positive. The diagnosis of multiple skin metastases was confirmed by histology of a resected skin nodule. The patient was treated with palliative chemotherapy. He died 6 months later of disease progression.