Metachromatic leukodystrophy and coincidental finding of papillomatosis of the gallbladder. A case report

Lysosomal storage diseases

Lysosomes are cytoplasmic organelles that contain a variety of different hydrolases. A genetic deficiency in the enzymatic activity of one of these hydrolases will lead to the accumulation of the material meant for lysosomal degradation. Examples include glycogen in the case of Pompe disease, glycosaminoglycans in the case of the mucopolysaccharidoses, glycoproteins in the cases of the oligosaccharidoses, and sphingolipids in the cases of Niemann-Pick disease types A and B, Gaucher disease, Tay-Sachs disease, Krabbe disease, and metachromatic leukodystrophy. Sometimes, the lysosomal storage can be caused not by the enzymatic deficiency of one of the hydrolases, but by the deficiency of an activator protein, as occurs in the AB variant of GM2 gangliosidosis. Still other times, the accumulated lysosomal material results from failed egress of a small molecule as a consequence of a deficient transporter, as in cystinosis or Salla disease. In the last couple of decades, enzyme replacement therapy has become available for a number of lysosomal storage diseases. Examples include imiglucerase, taliglucerase and velaglucerase for Gaucher disease, laronidase for Hurler disease, idursulfase for Hunter disease, elosulfase for Morquio disease, galsulfase for Maroteaux-Lamy disease, alglucosidase alfa for Pompe disease, and agalsidase alfa and beta for Fabry disease. In addition, substrate reduction therapy has been approved for certain disorders, such as eliglustat for Gaucher disease. The advent of treatment options for some of these disorders has led to newborn screening pilot studies, and ultimately to the addition of Pompe disease and Hurler disease to the Recommended Uniform Screening Panel (RUSP) in 2015 and 2016, respectively.

Gallbladder abnormalities in children with metachromatic leukodystrophy

BACKGROUND

Metachromatic leukodystrophy (MLD) is a lysosomal storage disease that leads to neurological deterioration and visceral involvement, including sulphatide deposition in the gallbladder wall. Using our institution's extensive experience in treating MLD, we examined the incidence of gallbladder abnormalities in the largest cohort of children with MLD to date.

METHODS

We conducted a retrospective review of all children with MLD, adrenoleukodystrophy (ALD), or Krabbe disease who underwent hematopoietic stem cell transplantation (HSCT) at our institution between 1994 and 2015. Baseline characteristics and unadjusted outcomes were compared using the Kruskal-Wallis test for continuous variables and Pearson χ² test for categorical variables, with significance defined as P < 0.05.

RESULTS

In total, 87 children met study criteria: 29 children with MLD and 58 children with ALD or Krabbe disease. Children with MLD were more likely to demonstrate gallbladder abnormalities on imaging, both before HSCT (41.4% versus 5.2%, P < 0.001) and after HSCT (75.9% versus 41.4%, P = 0.002). Consequently, a larger proportion of children with MLD underwent surgical or interventional management of biliary disease (10.3% versus 3.4%, P = 0.03).

CONCLUSIONS

Children with MLD have a significantly greater incidence of gallbladder abnormalities than children with other lysosomal storage diseases. Biliary disease should be considered in children with MLD who develop abdominal pain, and cholecystectomy should be considered for persistent, symptomatic gallbladder abnormalities.

The natural history and significance of ultrasonographically defined polypoid lesions of the gallbladder in children

BACKGROUND/PURPOSE

Gallbladder polyps are relatively common in adults and may increase the risk of gallbladder cancer. The increased use of high-quality abdominal ultrasonography has likely led to the increase detection of these lesions in the pediatric population. The aim of the present study was to address the significance of the ultrasonographic finding of a gallbladder polyp in children.

METHODS

This prospective case series of 4 children with ultrasonographically defined gallbladder polyps outlines their presentation and clinical course. A detailed review of the literature and a management approach has been provided.

RESULTS

In the 4 cases, polyps were followed for 2, 5, 72, and 84 months with a clinical follow-up of 7 to 11 years. Three underwent cholecystectomy and only 1 of 3 had a polypoid gallbladder lesion. One child, followed for 7 years, had no change in size, shape, or location of the polyp. This case series adds to the small group of children in the literature with polypoid gallbladder lesions and, to our knowledge, none have developed malignant transformation.

CONCLUSIONS

Clearly more studies on such children are required to further add to our knowledge on the natural history and the appropriate management of these lesions.