Niemann-Pick disease type B

Definition: NPD type B is a rare inborn error of metabolism of autosomal recessive inheritance. Patients with Niemann-Pick disease type B (NPDB) have a benign course and prognosis. It is mainly a visceral form without neurologic manifestations despite the massive visceral involvement. NPDB is caused by mutations in the acid lysosomal sphingomyelin phosphodiesterase-1 gene (SMPD1) (MIM.607608)

Digital slides

 Case 52 (HPC:52) : Liver in Niemann-Pick disease type B (NPDB)
 Case 129 (HPC:129) : Lung and liver in Niemann-Pick disease type B (NPDB)

Morphological synopsis

 foamy resident cells and histiocytes in several organs as lung, liver, spleen, kidney.

• microvacuolated hepatocytes (hepatic microsteatosis)

 large vacuolated foam cells (’NP cells’) on bone marrow biopsy
 sea blue histiocytes
 decreased platelets

Clinical synopsis

Patients with Niemann-Pick disease type B (NPDB) have a benign course and prognosis, while Niemann-Pick disease type A (NPDA) and Niemann-Pick disease type C (NPDC) are always associated with severe neurological involvement. They are known to be complicated with varying degrees of prognosis-determining liver dysfunction. It is mainly a visceral form without neurologic manifestations despite the massive visceral involvement.

 Onset in infancy or childhood
 Variable phenotype
 More common in Ashkenazi Jews
 Allelic disorder to Niemann-Pick disease type A (MIM.257200)
 short stature (less common)
 cherry-red maculae (less common)
 dyspnea
 frequent respiratory infections
 decreased pulmonary diffusion secondary to alveolar infiltration
 diffuse reticular or finely nodular infiltrations
 hepatomegaly
 progressive liver failure (#7655746#)
 splenomegaly
 absence of neurologic manifestations

Associations

 generalized AL amyloidosis of kappa type (#7655746#)

Ultrastructure

 foam cells with lamellar inclusions

Laboratory

 Decreased acid sphingomyelinase activity
 Increased LDL cholesterol
 Increased triglycerides
 Decreased HDL cholesterol

Etiology

 Caused by mutations in the acid lysosomal sphingomyelin phosphodiesterase-1 gene (SMPD1) (MIM.607608)

See also

 lysosomal storage diseases
 Niemann-Pick diseases (NPDs)

• Niemann-Pick disease type A (NPDA)
• Niemann-Pick disease type B (NPDB)
• Niemann-Pick disease type C (NPDC)

References

 Liver and Skin Histopathology in Adults With Acid Sphingomyelinase Deficiency (Niemann-Pick Disease Type B). Thurberg BL, Wasserstein MP, Schiano T, O’Brien F, Richards S, Cox GF, McGovern MM. Am J Surg Pathol. 2012 Aug;36(8):1234-46. PMID: #22613999#

 Takahashi T, Akiyama K, Tomihara M, Tokudome T, Nishinomiya F, Tazawa Y, Horinouchi K, Sakiyama T, Takada G. Heterogeneity of liver disorder in type B Niemann-Pick disease. Hum Pathol. 1997 Mar;28(3):385-8. PMID: #9042807#