Cavitating pulmonary nodules in histiocytosis-X high resolution CT demonstration.

In a case of pulmonary histiocytosis, high resolution C.T. scanning (H.R.C.T) showed multiple small ring shaped peripheral pulmonary lesions. This has not, to our knowledge been previously reported in the radiological literature. The possible pathogenesis of these lesions is described. With the advent of H.R.C.T this appearance should become more widely recognised in the future. H.R.C.T was of considerable assistance in diagnosis of this patient with non-specific findings on the plain chest film.