[A case of silicotuberculosis with difficulty in its diagnosis].

A 68-year-old man who had worked as a stone mason for more than 50 years with a heavy smoking history consulted our clinic with symptoms of cough, low grade fever, weightloss, malaise and a single expectoration of hemo-sputum. He had been diagnosed as silicosis by the mass survey 5 years ago based on nodular shadows with egg-shell calcification in hilar lymphnodes on his chest radiography, and has received chest radiographic examination once a year. As the author was not so familiar with the radiographic features of silicotuberculosis, it was difficult to interprete ill-defined contour of silicotic nodules accompanied by patchy opacities formation in right midlung field and silicotic conglomeration accompanied by an ischemic cavity in the left basal segments. A definitive diagnosis could not be established until 10 months later when a second attack of exacerbation of silicotuberculosis occurred showing multiple thin walled fresh tuberculous cavities on the chest radiography with positive smear and culture. Among multiple tuberculous cavities, there was a cirrhotic-walled cavity caused by endogenous reactivation of a quiescent tuberculous lesion on the right apex. This lesion was considered to be the source of dissemination of this case. Finally, it took about two and a half years before establishing the diagnosis in this case because of a series of doctors delays. He was treated successfully with antituberculous drugs for one and a half years including one year rifampicin medication. The clinico-pathological findings of silicotic conglomeration in the left basal segments were discussed based on the findings of transbronchial biopsy from occluded B10 and chest radiographic findings, and it was revealed that silicotic conglomeration might consist of inflammatory granulation combined with granulomatous tubercle, but not a fibrous lesion.