Metachromatic leukodystrophy and its effects on the gallbladder: a case report.

Metachromatic leukodystrophy (MLD) is an autosomal recessive lysosomal storage disorder caused by a deficiency of arylsulfatase A enzyme. This deficiency leads to accumulation of sulfatides in the central nervous system and other organs, such as the gallbladder. Here the authors discuss a 9-year-old Middle Eastern patient with late-infantile-type MLD who presented with symptoms of cholecystitis. Radiographic studies revealed an enlarged gallbladder with a thickened wall and a pericholecystic fluid collection with peripheral calcifications. Gross examination of the gallbladder showed multiple small to medium-sized papillary projections involving the entire mucosal surface. Sections through the gallbladder wall revealed multilocular dilated mucin-producing cystic spaces. Microscopically, the mucosa showed numerous papillary projections with complex folds lined by mucin-producing cuboidal to tall columnar cells. The cystic spaces were composed of numerous markedly distended Rokitansky-Aschoff sinuses filled with mucin. Ultrastructurally, the epithelial cells and macrophages showed frequent secondary lysosomes containing closely packed lamellar amorphous to prismatic material with alternating leaflets and tubules, imparting a "herringbone" or "tuffstone" pattern. This case illustrates the features of gallbladder involvement in MLD and the potential role of ultrastructural examination in diagnosis of MLD.