Focal Organizing Pneumonia: CT and Pathologic Findings

Abstract

The purpose of this study was to describe the CT findings of focal organizing pneumonia and to compare the findings with pathology. CT findings of histologically proven focal organizing pneumonias in 26 consecutive patients were analyzed. In 17 patients who had undergone surgical resections, the findings were correlated with pathology. Focal organizing pneumonias appeared as a nodule (n= 13) or a mass (n=13), ranging from 9 mm to 66 mm in diameter. Ground-glass opacity was seen in 6/13 (46%) nodules and 6.5/13 (50%) masses (k=.48) with an extent ranging from 5% to 75% (mean, 16%). In 4/26 (15%) patients, the extent was more than 50% of the lesion. They showed smooth (n=4), lobulated (n=8), spiculated (n=1), or lobulated and spiculated margin (n=13). On correlative analysis, nodule or mass on CT consisted histologically of intraalveolar exudate or microabscess, chronic inflammatory cell infiltration, fibrotic nodules, and polypoid granulation tissue in the alveolar or bronchiolar spaces. Ground-glass opacity consisted of interstitial fibrosis and chronic inflammatory cell infiltration and intraalveolar polypoid granulation tissue. Focal organizing pneumonia may simulate a lung cancer with variable appearances on CT and the findings reflect underlying histopathology of the disease.

A Case of Adult Onset Still's Disease Complicated with Cryptogenic Organizing Pneumonia

“…Some cases overlap with other types of idiopathic interstitial pneumonias (IPF), especially IPF and nonspecific interstitial pneumonia (NSIP). In the latter, focal areas of organizing pneumonia are often encountered at histopathology (18). The radiographic findings of the present case showed solitary focal opacity and the patient had no respiratory symptoms.…”

Cryptogenic organising pneumonia

“…The lesions are often located in the upper lobes, and may be cavitary. The clinical presentation may be that of COP as described above, but focal organising pneumonia may be totally asymptomatic and discovered by routine chest radiographs (some patients may recall that they had a previous history of pneumonia) [17,90,145]. The suspicion of carcinoma may be increased by false-positive fluorodeoxyglucose positron emission uptake [147,148].…”

“…However, organising pneumonia is distinct from round pneumonia improving with antibiotics [142][143][144]. Neutrophilic inflammation or microabscesses may be associated with the typical features of organising pneumonia [145,146]. The lesions are often located in the upper lobes, and may be cavitary.…”

Quantitative MDCT analysis of pulmonary solid nodules using three parameters

“…In addition, it has been reported that 69%-94% of the nodules of organizing pneumonia had irregular margins, suggesting lower compactness. 16,22 The mean compactness of organizing pneumonia, adenocarcinoma, and squamous cell carcinomas was low, and a signifi cant difference was not noted among these three diseases. Metastasis showed the second largest value after hamartoma.…”