Background Gross Pathology Histopathology & Immunohistochemistry

BACKGROUND AND CLINICAL INFORMATION: Head

Summary: Mucopolysaccharidoses are characterized by abnormal lysosomal accumulation of mucopolysaccharides or glycosaminoglcan resulted from deficiency of a lysosomal glucosidase or sulfatase. Common to all mucosaccharidoses are dysmorphic changes and excretion of mucopolysaccharides in urine. The CNS is affected to different extents in different subtypes and only type IH and III have severe effects on the CNS. See also mucosulfatidosis.

Clinical subtypes:

Hurler (MPS IH)
Scheie disease (MPS IS or V)
Hunter (MPS II)
Sanfilippo (MPS III)
Morquio (MPS IV)
Maroteaux-Lamy (MPS VI)
Sly (MPS VII)

GROSS PATHOLOGY: Head

The brain usually normal appearance but the skull may be thickened. Dura and leptomeninges may be opaque. Perivascular pits are often noted on cut sections.

HISTOPATHOLOGY AND IMMUNOHISTOCHEMISTRY: Head

Histology:

Mucopolysaccharide: Common to all types of mucopolysaccharidoses is abnormal lysosomal storage of mucopolysaccharides. Mucopolysaccharides are highly water-soluble and cannote be demonstrated on routine sections.
Ganglioside: Neurons may have significant ganglioside storage giving rise to cells suggestive of gangliosidoses, but storage may not be obvious particularly in subtypes without mental retardation. The stored gangliosides are PAS(+), sudanophilic (+), and Luxol fast blue (+). Neuronal storage is present throught the brain and spinal cord and ganglia of gastrointestinal tract in type IH, IH/S, II, III, and VII.
Other organs: Storage material can be found in hepatocytes and Kuffer cells, spleen, cartilage, lymph nodes, tonsils, kidney and heart. Alder granules (reddish violet granulation in neutrophils with Wright stain) in peripheral blood (type VI and VII). Vacuolated lymphocytes are not usually prominent (except in IVB). Occasional Gasser cells (vacuolated lymphocytes with basophilic inclusions) may be seen in any of the subtype.

Electron microscopy:

Mosy cell types: Large membrane-bound, largely empty vacuoles that sometimes contain lamellae.
Neuronal storage: The storage material essentially has features of primary gangliosidosis. Some of them appear concentric, tightly packed lamellae while others contain loosely arranged, parallel arrays of lamellae giving rise to the so-called zebra bodies. Although zebra bodies are regarded as a typical finding in mucopolysaccharides, they are also seen in other storage diseases.

NeuroLearn NeuroHelp Metabolic For Comment: KarMing-Fung@ouhsc.edu

Background Gross Pathology Histopathology & Immunohistochemistry