Acid sphingomyelinase deficiency (ASMD; also known as
Niemann-Pick Disease [
NPD] A and B) is a rare
lysosomal storage disease characterized by the pathological accumulation of
sphingomyelin within multiple cell types throughout the body. The infantile neurovisceral (ASMD type A, also known as
Niemann-Pick Disease type A) form of the disease is characterized by markedly low or absent
enzyme levels resulting in both visceral and severe neurodegenerative involvement with death in early childhood. We report here the
clinical course and autopsy findings in the case of a 3 year old male patient with infantile neurovisceral ASMD. A comprehensive examination of the autopsy tissue was conducted, including routine
paraffin processing and staining, high resolution light microscopy and staining for
sphingomyelin, and ultrastructural examination by electron microscopy. Profound
sphingomyelin accumulation was present in virtually every organ and cell type. We report the clinicopathologic correlations of these findings and discuss the relevance of these results to the clinical practice of physicians following all patients with ASMD. This case represents one of the most extensive and detailed examinations of ASMD type A to date.