"Blue bodies" in a case of cryptogenic fibrosing alveolitis (desquamative type) an ultra-structural study

Frequency of "blue bodies" in pulmonary cytology specimens

To determine the frequency of occurrence of "blue bodies" (BBs), 2,010 pulmonary cytology specimens (1,403 sputum and 607 bronchial specimens) from 1985 were reviewed. The smears were examined microscopically by transmitted and polarized light. BBs were extracellular structures, occurring most commonly in clusters but sometimes conglomerated. With Papanicolaou stain, they had a characteristic birefringent laminated brown core and a nonbirefringent blue rim. Chemical microanalysis and energy-dispersive x-ray analysis revealed that their chemical composition was calcium carbonate. A total of 233 specimens contained BBs, with a frequency of 10.5% in bronchial specimens and 12% in sputum. Only 8.6% of the BBs had co-existent pulmonary malignancy. We concluded that BBs were common structures in pulmonary cytology and were not associated with pulmonary malignancy or pulmonary fibrosis in our series. They must be distinguished from contaminants, staining artifacts, and parasitic ova.

Pulmonary blue bodies

Pulmonary blue bodies are intra-alveolar laminated basophilic concretions of uncertain etiology. Blue bodies were studied in lung biopsy specimens from 10 patients. The patients ranged in age from 47 to 69 years and were predominantly men. Three had a history of overt exposure to environmental dusts such as sawdust and asbestos, and two showed occasional ferruginous bodies in the lung, raising the possibility of pneumoconiosis. In eight cases there was interstitial pneumonitis, which resembled desquamative interstitial pneumonia by light microscopy but which was often seen to be patchy and asymmetrically distributed in the lung by chest x-ray examination. Of two other patients, one had xanthogranulomatous inflammation and the other, necrotizing granulomatous inflammation. Light and electron microscopic, histochemical, microchemical, and x-ray diffraction studies of blue bodies were also performed. Calcium carbonate is a major component of blue bodies and is responsible for their birefringence in unstained sections and ready solubility in acid solutions. Blue bodies also contain a mucopolysaccharide matrix and iron. We offer the hypothesis that blue bodies (calcium carbonate) are a product of histiocytic catabolism.