Miscellaneous



Pulmonary histiocytosis X, or eosinophilic granuloma of the lung, is a relatively benign dis­ease presenting with dyspnea and x-ray evidence of diffuse nodular or reticulonodular infiltrates with relative sparing of the lung bases. It should be suspected in patients in the third and fourth decades presenting with diffusely abnormal chest x-rays. It is easy to confuse with sarcoidosis, al­though pneumothorax or honeycombing on the chest x-ray and the rarity of hilar adenopathy favor histiocytosis X. Diagnosis is made patho­logically, treatment is uncertain, and spontaneous remissions are common.

The lymphocytic infiltrative disorders include lymphocytic interstitial pneumonia and immu-noblastic lymphadenopathy, among other specific entities. They differ from other interstitial lung diseases by their common association with dys-proteinemia and frequent progression to lym­phoid malignancy.

Pulmonary alveolar proteinosis is a rare, idi­opathic disease in which the alveoli become filled with a proteinaceous material rich in lipids. Most patients recover spontaneously, but total lung la­vage is necessary when diffuse involvement causes severe hypoxemia. These patients are par­ticularly prone to infection with Nocardia, and less so to Aspergillus and Cryptococcus.