Pulmonary Hyalinizing Granuloma Associated with Idiopathic Thrombocytopenic Purpura

Pulmonary hyalinizing granuloma (PHG) is a rare, benign lung disease of unknown etiology. It manifests as discrete, rounded nodules within the lung parenchyma. A 39-year-old woman presented for investigation after pulmonary nodules were found incidentally. Chest computed tomography showed multiple, discrete, non-enhancing pulmonary nodules bilaterally. Positron emission tomography (PET) was negative. Biopsy demonstrated a non-specific lymphoplasmacytic infiltrate. Open resection yielded two nodules consistent with hyalinizing granulomas. The differential for multiple pulmonary nodules is broad. PET scan can help rule out metastatic disease, although some cancers are not hypermetabolic on PET. Furthermore, some non-malignant conditions, including hyalinizing granuloma, can show increased activity on PET. PHG should be included in the differential of multiple pulmonary nodules, especially if nodule stability can be demonstrated and/or needle biopsies are non-diagnostic. Associated immune-mediated conditions, such as idiopathic thrombocytopenic purpura (ITP) in our patient, may also favor HG. In this case report we find an association between PHG and ITP.