A case of poorly differentiated mucinous carcinoma of the gallbladder that exhibited a peculiar morphology.

A 65-year-old female presented with an elevated lesion that was identified in the gallbladder fundus via abdominal ultrasound during a medical checkup. The tumor was a pedunculated lesion, measuring 30mm in diameter, that exhibited a blood flow pattern with gradual dense staining throughout the equilibrium phase on the abdominal contrast computed tomography and a high signal intensity on T2-weighted magnetic resonance imaging. Histopathological findings revealed the proliferation of poorly differentiated adenocarcinoma, including signet ring cells, throughout the tumor along with the formation of a mucous lake. The patient was consequently diagnosed with poorly differentiated mucinous carcinoma of the gallbladder.