Mucin-containing Rokitansky-Aschoff Sinuses With Extracellular Mucin Deposits Simulating Mucinous Carcinoma of the Gallbladder

Intracystic papillary neoplasm with an associated mucinous adenocarcinoma arising in Rokitansky-Aschoff sinus of the gallbladder

Intraepithelial neoplasias are preinvasive neoplastic lesions found throughout in the digestive system, and when such lesions are discovered in the gallbladder, they are referred to as intracystic papillary neoplasm (ICPN). In the gallbladder, mucinous adenocarcinoma is a rare histologic phenotype, and adenocarcinomas involving Rokitansky–Aschoff (RA) sinuses are uncommon, which were indeed found in a case reported here. A 64-year-old male presenting with upper abdominal pain demonstrated a spherical mass protruding outward from the gallbladder fundus in imaging studies. Laparoscopic cholecystectomy was performed, and the resected specimen revealed a subserosal cystic mass with a small communication with the gallbladder lumen. The cystic mass contained a gelatinous material without solid component. Histologically, the mass was consisted of subserosal cysts lined by atypical columnar mucinous epithelium with micropapillary growth and nuclear stratification. The neoplastic transformation was more pronounced toward the serosal side of the lesion where disruption of the cyst wall, intrastromal mucin lakes, and invasion of the neoplastic cells into surrounding stroma were observed. The epithelium was of intestinal lineage, which was supported by the positive immunoreactivity against CDX2 and MUC2. The cystic spaces were communicated with surrounding RA sinuses, which indicated that the tumor arose in the sinus. The pathological diagnosis was ICPN, intestinal type, with an associated mucinous adenocarcinoma arising in RA sinus.

Pathology of the gallbladder in a child with metachromatic leukodystrophy

Metachromatic leukodystrophy (MLD) is an autosomal recessive lysosomal storage disease caused by deficient activity of arylsulfatase A, leading to an accumulation of sulfatide in myelinating cells and progressive central and peripheral demyelination. Sulfatide also accumulates in various organs, most notably the gallbladder. Gallbladder mucosal hyperplasia with papillomatosis, in the setting of abdominal pain and hemobilia, is often demonstrated by sonography. We present a histologic and ultrastructural description of these alterations in a 5-year-old girl with MLD who presented with abdominal pain and feeding intolerance. Gross and light microscopic analysis demonstrated diffuse villous hyperplasia of the gallbladder mucosa with intraepithelial and intravillous macrophage accumulations of metachromatic material. Electron microscopic analysis demonstrated this material to comprise numerous membrane-bound inclusions composed of concentrically lamellated, dense material. The rarity of descriptions of this finding prompted this case report.