Proposed criteria for mixed-dust pneumoconiosis: Definition, descriptions, and guidelines for pathologic diagnosis and clinical correlation 1 1 The NIKKO-Symposium on Mixed-Dust Pneumoconiosis was held October 18-19, 1997, in Nikko, Tochigi, Japan, to develop diagnostic criteria for mixed-dust pneumoconiosis under the auspices of Labour Welfare Corporation, Tokyo, Japan. The Organizing Committee included Keizo Chiyotani, Koichi Honma, Yutaka Hosoda, and Hisao Shida, and participants included Zol

• Published in: Human pathology 2004-12, Vol.35 (12), p.1515
• Main Authors: Honma, Koichi, Abraham, Jerrold L, Chiyotani, Keizo, De Vuyst, Paul, Dumortier, Pascal, Gibbs, Allen R, Green, Francis H.Y, Hosoda, Yutaka, Iwai, Kazuro, Williams, William Jones, Kohyama, Norihiko, Ostiguy, Gaston, Roggli, Victor L, Shida, Hisao, Taguchi, Osamu, Vallyathan, Val
• Format: Article
• Language: English
• Subjects: Dust; Lungs; Respiratory diseases; Tuberculosis
• ISSN: 0046-8177; 1532-8392
• DOI: 10.1016/j.humpath.2004.09.008

We defined mixed-dust pneumoconiosis (MDP) pathologically as a pneumoconiosis showing dust macules or mixed-dust fibrotic nodules (MDF), with or without silicotic nodules (SN), in an individual with a history of exposure to mixed dust. We defined the latter arbitrarily as a mixture of crystalline silica and nonfibrous silicates. According to our definition of MDP, therefore, MDF should outnumber SN in the lung to make a pathologic diagnosis of MDP. In the absence of confirmation of exposure, mineralogic analyses can be used to support the pathologic diagnosis. The clinical diagnosis of MDP requires the exclusion of other well-defined pneumoconioses, including asbestosis, coal workers' pneumoconiosis, silicosis, hematite miners' pneumoconiosis, welders' pneumoconiosis, berylliosis, hard metal disease, silicate pneumoconiosis, diatomaceous earth pneumoconiosis, carborundum pneumoconiosis, and corundum pneumoconiosis. Typical occupations associated with the diagnosis of MDP include metal miners, quarry workers, foundry workers, pottery and ceramics workers, and stonemasons. Irregular opacities are the major radiographic findings in MDP (ILO 1980), in contrast to silicosis, in which small rounded opacities predominate. Clinical symptoms of MDP are nonspecific. MDP must be distinguished from a variety of nonoccupational interstitial pulmonary disorders.