Bronchoalveolar lavage in idiopathic pulmonary fibrosis: what does it tell us?

Bronchoalveolar lavage (BAL) has only a limited role in diagnosis of idiopathic pulmonary fibrosis (IPF). A finding of raised neutrophils (>5%) and eosinophils (>2%) is characteristic but not diagnostic of IPF. BAL cell count does not clearly differentiate between fibrotic non-specific interstitial pneumonia and IPF either diagnostically or prognostically. BAL in IPF should be considered in all patients with suspected infection, malignancy or acute exacerbations. In such cases, it may be diagnostic. Because of few and conflicting results BAL fluid analysis has very little clinical relevance determining prognosis and response to treatment in IPF.

Granulomatous lung disease.

Granulomas are a frequent challenge for pathologists, which can be identified both in histological and cytological material in a number of conditions. With regard to interstitial lung diseases, granulomas can be associated with infection (e.g. mycobacterial), immunological conditions (e.g. hypersensitivity pneumonitis), or may be idiopathic (e.g. sarcoidosis). Considering morphology, features that should be identified are the presence of necrosis, the cohesiveness and coalescence of granulomas, the presence of fibrosis and the amount and quality of the associated inflammatory infiltrate. The most interesting approach to granulomatous lung disease is indeed represented by their pattern of distribution within the secondary lobule; in fact, granulomas can be distributed along lymphatic routes (e.g. sarcoidosis), randomly (miliary infections, e.g. mycobacterial and fungal infections), or along the airways (hypersensitivity pneumonitis, hot tub lung, aspiration pneumonia and sometimes infections). We propose a combined radiological-histopathological approach for defining the morphological features and anatomic localization of granulomatous ILDs. In addition, a detailed review of their clinical features is provided, together with a description of the main procedures used to obtain respiratory samples for pathology and microbiology studies in these patients.