Introduction: The discovery of anthracotic plaques generally suggests either a history of tuberculosis or occupational exposure to dust. Other etiologies should, however, be considered.
Case reports: A 60-year-old Iranian woman presented with a history of dyspnoea and with chest radiography demonstrating calcified hilar lymph nodes and interstitial lung disease. Pulmonary function tests revealed airway obstruction. A diffuse bronchial inflammatory appearance accompanied by anthracotic plaques was found at bronchoscopy, which prompted transmission electron microscopy analysis of non-fibrous mineral particles in the bronchoalveolar lavage fluid (BALF). This demonstrated the presence of an alveolar particle count greater than 10(7) particles/ml (p/ml), significantly more than that found in 42 BALF samples taken from controls without a history of occupational dust exposure (4,4.10(5) p/ml). Furthermore, the analysis also revealed an abnormally elevated proportion of mica particles (64%). Two other individuals, a 68 year-old Moroccan woman and a 70-year-old Algerian woman, who had anthracotic plaques, but no radiological evidence of interstitial lung disease, also underwent mineral analysis of BALF. Neither were found to have a raised alveolar particle count, but the mineral profile showed an abnormally elevated proportion of micas (62%) for one patient, and silica crystalline (40%) as well as micas (32%) for the other patient.
Conclusions: Even if mica is present in 30 to 90% of the BALF, the results observed in these three patients raises the possibility of non-occupational environmental exposure and that anthracotic plaques might be associated with domestic pollution.