Adult niemann-pick disease: A case report

Niemann-Pick disease (NP) is a rare lysosomal storage disorder, inherited in an autosomal recessive manner. It is a sphingomyelin-cholesterol lipidosis associated with the accumulation of foam cells. It is divided into two entirely distinct entities on metabolic, biochemical, and genetic levels: NP A/B and NP C.

Diagnosis is established by clinical and biological presentation, notably through bone marrow examination (myelogram), and low enzymatic activity of acid sphingomyelinase for types A and B. Whereas for type C, the filipin test on cultured skin fibroblasts is no longer considered the gold standard; new diagnostic approaches are currently being investigated.

Genetics remains highly preferred for diagnosis. Normal enzymatic levels do not exclude the diagnosis in the presence of a highly suggestive clinical phenotype. The aim of our study is to present the clinical, biological, histological, and radiological aspects of Niemann-Pick disease, in the context of a clinical case of a male patient hospitalized in the Hematology Department at Avicenne Military Hospital in Marrakech.

We report the case of a 57-year-old patient, born of consanguineous marriage, with a personal history of appendectomy and a family history of a brother treated for and deceased from tuberculosis. The patient was admitted for progressive abdominal pain and left hypochondrial heaviness. Clinical examination revealed splenomegaly and osteoarticular pain on palpation, associated with nocturnal sweats evolving in the context of a general deterioration of health. The myelogram revealed numerous very large foam cells with cytoplasm filled with blue granulations stained by May Grunwald Giemsa (MGG), giving a characteristic "sea blue" appearance typical of Niemann-Pick disease. Biochemistry showed disrupted lipid profiles with collapsed HDL cholesterol in the absence of enzymatic alteration of acid sphingomyelinase. Histology revealed macrophage overload with foam-like cytoplasm appearing sea blue. Imaging confirmed nodular splenomegaly.

With this data, the diagnosis of Niemann-Pick disease type B was made, despite the absence of enzymatic imbalance, which is only specific in cases of deficiency. This highlights the complexity of the diagnosis.Haut du formulaire

Our study demonstrates that the myelogram is a crucial examination for the detection of Niemann-Pick disease. The normal enzymatic assay despite a typical phenotype of Niemann-Pick type B highlights the complexity of the diagnosis and the lack of specialized laboratories for these assays.