[Nine cases of pulmonary sarcoidosis predominantly affecting the lower lung fields]

Pulmonary sarcoidosis which predominantly affects the lower lung fields is relatively rare. We performed this study to clarify the clinical manifestations of this type of sarcoidosis.

Over a period of 13 years, we diagnosed pulmonary sarcoidosis in 119 patients. Among these, we reviewed the clinical characteristics of 9 patients (3 men, 6 women, mean age 62 years) with pulmonary lesions predominantly affecting the lower lung fields.

Four patients had a history of dust inhalation and 6 had symptoms of dyspnea. All patients had ocular lesions and 5 had cutaneous lesions. Serum KL-6 levels were elevated in all patients, whereas angiotensin-converting-enzyme (ACE) levels were elevated in 3. Pulmonary function tests revealed stenosis in 4 patients, and decreased diffusion capacity in 7. Chest CT findings in the lower lung fields revealed bronchovascular thickening, micronodular opacities in the vessels and chest wall, and interlobular septal thickening in 8 patients; ground-glass opacities in 5; curvilinear shadows in 4; and patchy shadows, traction bronchiectasis, and pleural effusion in 3. Histopathologic findings of lung biopsy specimens featured granulomas in all patients, and pulmonary interstitium fibrosis and small round-cell infiltration in the alveoli of most patients.

Patients with sarcoidosis affecting the lower lung fields often had symptoms of dyspnea, extrapulmonary lesions in the eye and/or on the skin, and elevated serum KL-6 levels but not ACE. Chest CT showed findings typical of sarcoidosis, such as lymphatic distribution, but also showed unusual findings such as ground-glass opacities, curvilinear shadows, patchy shadows, traction bronchiectasis and pleural effusion. We speculated that 1 patient with ground-glass opacities and traction bronchiectasis without lymphatic distribution on CT, and fibroblastic foci with active alveolitis histopathologically, had complications of a different type of interstitial pneumonia.