The man, 57 years old, truck driver, is a former smoker of 54 pack/years. He has arterial hypertension, type 2 diabetes mellitus, chronic renal failure with mild anemia and an obstructive sleep apnea syndrome (OSAS) in severe obesity. As his wife, he has got a herpes simplex virus type I infection. He takes regular therapy with aspirin, doxazosin, allopurinol, irbesartan, erythropoietin and insulin. He referred dyspnea ATS grade II-III in the absence of cough. He also reported to have taken steroids in the past at the starting dose of 50 mg/day and gradually tapered. This therapy was recommended in the absence of a definitive diagnosis and on the basis of symptoms and radiological abnormalities of "interstitial thickening" present in the chest x-ray. At the time of our first observation, the pulmonary function tests revealed a mild restrictive pattern with reduction of DLCO (Table 2). The 6-min walking test showed that the distance walked during sub-maximal exercise was below the lower normal limit. The high-resolution chest CT scan showed "areas of increased ground-glass density in the right lower lobe, with parenchymal micro-nodules in the following lobes: left upper, lingula, left lower, middle, and right lower; multiple enlarged lymph nodes are present in the mediastinum, at the following areas: retrotracheal, paratracheal, aortopulmonary window, subcarinal and bilateral hilar; other enlarged lymph nodes are present at the origin of neck vessels, in the supraclavicular zone, and (in scans passing through the upper abdomen) bilaterally along the celiac tripod, peripancreatic area, along the gastro-lienal and epatogastric ligament". Both patients underwent bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB). The BAL fluid revealed a mild lymphocytic alveolitis both in the man (L = 22%) and in the woman (L = 18%) with a CD4/CD8 ratio of 3.1 in the former and 2.8 in the latter. The microbiological analysis of the BAL fluid was negative for common bacterial, tubercular and fungal infections. The TBB was non-diagnosticboth in man and in woman due to a poor and non-representative lung sample. For these reasons both patients underwent lymph node biopsy by mediastinoscopy which showed a "granulomatous epithelioid giant cell non-necrotising chronic lymphadenitis".