Differential Langerhans’ cell histiocytosis

The most important differential diagnoses for LAM are Langerhans cell histiocytosis, idiopathic pulmonary fibrosis, and panlobular emphysema. In contrast to LAM, in Langerhans cell histiocytosis, the costophrenic sulci are usually spared, the cysts can be thick-waUed and irregularly outlined, and nodules are predominant in the early stage of disease. Idiopathic pulmonary fibrosis shows a volume loss in contrast to LAM, and the honeycomb cysts are predominantly located in the lower lobes and subpleural (Bonelli et al. 1998). Panlobular emphysema is associated with alpha-1-antiprotease deficiency. The most distinct feature of emphysema is the absence of defined walls in the areas of low attenuation, whereas cysts in LAM almost invariably present with walls (Johnson 1999). 

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