Isolated diffuse bone marrow metastasis from signet-ring cell gastric carcinoma

A 71-year-old female patient with a known history of signet-ring cell carcinoma presented with diffuse bone pain and anemic symptoms. An 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography study was performed, revealing the presence of diffuse heterogeneous hypermetabolic sclerotic lesions in the axial and proximal appendicular skeleton. No other FDG-avid lesion was detected. Subsequent bone marrow biopsy confirmed the diagnosis of metastatic carcinoma, originating from the gastric primary site. Palliative treatment was initiated; however, the patient's condition deteriorated, and she succumbed to the disease two months later.