Granular cell tumor of the common bile duct: A Japanese case

Figure 1 Upon abdominal ultrasound, the gallbladder was swollen. Dilatation of the bile duct was not apparent upon measurement, however, a segment of the common bile duct seemed to be obstructed, warranting further investigation.

Figure 2 Endoscopic retrograde cholangiopancreatography shows stricture at the middle part of the bile duct.

Figure 3 The pathological result of the tumor. A: Neoplastic cells of granular cell tumor infiltrates the mucous membrane epithelium of the bile duct (Elastica-Masson stain, × 1.25); B: Granular cells (HE stain, × 10).

Figure 4 The granular cell tumor cells partially infiltrated a peripheral nerve fibrous tissue bunch in the bile duct wall. In addition, they infiltrated the vein in the bile duct wall and occluded some of the vein lumina. A: Granular cell tumor involving a small nerve (Elastica-Masson stain, × 4); B: A vein is replaced by a neoplastic cell (Elastica-Masson stain, × 4).