An AIDS patient with a cavitary lung lesion was found to have
pulmonary malacoplakia associated with Rhodococcus equi
infection. The diagnosis was based on the typical histologic
features of transbronchial biopsy and a positive bacterial culture. All
13 reported cases of AIDS patients with pulmonary malacoplakia were
associated with R equi. The recognition of this unique
entity is important because of its responsiveness to therapy.