A very unusual presentation of Niemann-Pick disease type B in an infant: similar findings to congenital lobar emphysema.

The main features of Niemann-Pick disease type B (NPD-B) are enlargement of the liver and spleen, and mild pulmonary involvement. Recurrent respiratory tract infection and progressive decline in pulmonary function are major contributors to morbidity and mortality in this patient group. Massive pulmonary involvement in early life is extremely rare. The most common finding on chest X-rays of NPD-B patients is reticular or nodular infiltration of the lungs. This article describes a very rare presentation of NPD-B in an infant who had suffered recurrent respiratory tract infections. Massive emphysema and marked infiltrative parenchymal changes (infiltration of the parenchyma) were initially attributed to congenital lobar emphysema and its compressive effects. However, NPD was suspected when a lung biopsy showed foamy cells and sea-blue histiocytes were detected in a bone marrow biopsy. The definitive diagnosis was established with an enzyme study for sphingomyelinase.