Fulminant disseminated carcinomatosis of the bone marrow from pancreatic mucinous carcinoma with predominant signet ring cell morphology.

Disseminated carcinomatosis of the bone marrow (DCBM) is a rare and highly aggressive form of bone metastasis arising from solid tumors, most commonly gastric cancers. DCBM originating from pancreatic cancer is exceedingly rare, with only a few cases reported in the literature. A 62-year-old man presented with back pain, loss of appetite, and weight loss. Laboratory tests revealed anemia and thrombocytopenia. Contrast-enhanced computed tomography revealed a hypovascular mass measuring approximately 10 mm in size in the pancreatic tail. Endoscopic ultrasound-guided fine-needle aspiration confirmed the diagnosis of pancreatic mucinous carcinoma. Laboratory evaluation suggested disseminated intravascular coagulation (DIC). Although no nodular bone metastases were detected on imaging studies, bone marrow biopsy revealed diffuse infiltration by adenocarcinoma predominantly composed of tumor cells with signet ring cell carcinoma morphology, leading to a diagnosis of DCBM from pancreatic mucinous carcinoma. The patient developed a subarachnoid hemorrhage due to severe bleeding tendency, and chemotherapy could not be initiated. The patient died on hospital day 11. To our knowledge, this is the first reported case of DCBM arising from pancreatic mucinous carcinoma with bone marrow metastasis predominantly composed of signet ring cell carcinoma morphology. In patients with pancreatic cancer who present with DIC, particularly mucin-producing tumors such as mucinous carcinoma, the possibility of DCBM should be actively suspected, and early bone marrow aspiration and biopsy should be considered.