A case of surgical resection for well-differentiated squamous cell carcinoma arising in a ciliated hepatic foregut cyst

抄録

Ciliated hepatic foregut cysts (CHFC) are extremely rare, and most are benign cysts of the liver arising from remnants of the embryonic foregut. CHFC is usually found incidentally and as mostly asymptomatic cysts. We report squamous cell carcinoma (SCC) arising in a CHFC in a 50-year-old Japanese woman. She consulted our hospital for upper abdominal pain. A computed tomography and an ultrasound showed a cystic region including calcification and a solid mass in segment 4 of the liver. Left hepatectomy, B6 bile duct resection, and biliary-jejunal anastomosis were performed. Microscopic examination revealed that part of the cyst was lined by a characteristic ciliated pseudostratified columnar epithelium surrounding a connective tissue, a slightly thick fibrotic smooth muscle stromal layer, and an outer fibrous capsule. The cyst wall contained a low-papillary mural nodule showing atypical squamous hyperplasia with high-grade dysplasia. Stromal invasion was identified at the base of the nodule, leading to the diagnosis of well-differentiated SCC arising from a CHFC. We recommend careful clinical follow-up for patients with relatively large CHFCs as potentially malignant lesions and excision if they show any clinical manifestation.