Bronchiolitis obliterans organizing pneumonia associated with essential mixed cryoglobulinemia.

Bronchiolitis obliterans organizing pneumonia (BOOP) is an uncommon and underrecognized pathologic finding observed in a variety of syndromes including connective tissue diseases. Although lung involvement in essential mixed cryoglobulinemia (EMC) has been reported, there are no previous reports of BOOP in EMC. We report herein a case of longstanding EMC associated with interstitial and cavitary lung disease histologically consistent with BOOP. A theory of a possible etiologic basis for the development of BOOP in patients with connective tissue diseases is discussed.