Radiographic Findings of Primary Lung Cancer with Delayed Detection on Chest Radiographs

PURPOSE: To analyze the causes of delayed detection of lung cancer on chest radiographs. MATERIALS AND METHODS: We retrospectively reviewed 105 cases in which an initial diagnosis of lung cancer, based on anexamination of plain radiographs, had been missed or misinterpreted. All occurred between October 1993 and April1997. We reviewed the initial chest radiographs and compared the features noted with those seen on later chestradiographs and computed tomographic (CT) images. RESULTS: Undetected lung cancer was identified in 56 patients(56/105, 53.3%) It had been hidden by superim-posed structures (41, 73.2%), overlapped by combined benign diseases(12, 21.4%), or the nodules were subtle(3, 5.4%). Of the 41 lung cancers hidden by a superimposed structure, thecentral type accounted for 29 (70.7%) and the peripheral type for 12 (29.3%). The 29 central type had been hiddenby the left hilum (n=15), the right hilum (n=10), the heart (n=3), or a rib (n=1). The twelve peripheral type werehidden by a rib (n=7), the heart (n=2), the diaphragm (n=2), or the left hilum (n=1). Of the 12 lung cancersoverlapped by combined benign diseases, pulmonary tuberculosis (n=6), pleural effusion (n=4), congestive heartfailure (n=1), and dif-fuse interstitial lung disease (n=1) were present at the time of interpretation. Themisinterpreted lung cancers were identified in 49 patients (49/105, 46.7%) and were seen to be combined withbenign disease (16, 32.6%), or as obstructive pneumonia without a central mass (15, 30.6%), air-spaceconsolidation (7, 14.3%), cavity (7, 14.3%), double lesion (2, 4.1%), or young age below 26 years (2, 4.1%). Ofthe 16 lung cancers misinterpreted as combined disease, pulmonary tuberculosis (n=14) and pleural disease (n=2)had been initially diagnosed. CONCLUSION: Most commonly, lung cancer was missed or misinterpreted because it washidden by a normal structure or combined with a benign disease. Perceptual errors can be reduced by appropriatetechniques and the scrutiny of trouble spots such as the parahilar, retrocardiac, retrodiaphragmatic and costalregions. Errors in the analysis of lung cancer can be reduced by increased awareness of growth patterns anduncommon man-ifestations of the disease.

Consolidation Type of Bronchioloalveolar Carcinoma and Necrotizing Pneumonia: Differential Diagnosis on CTScans

PURPOSE: To determine the CT findings which distinguish consolidation-type bronchioloalveolar carcinoma fromnecrotizing pneumonia. MATERIALS AND METHOD: This study involved ten patients with pathologically-provenconsolidation-type bronchioloalveolar carcinoma and 34 with necrotizing pneumonia proven pathologically either inthe laboratory or clinically. We retrospectively analyzed CT features including the enhancement pattern ofconsolidated lung, the presence and internal density of cavity within consolidated lung, CT angiogram sign,air-bronchogram, pleural enhancement, pleural effusion, and change in extrapleural tissue and its density. RESULT: CT findings in patients with necrotizing pneumonia showed higher attenuation in marginal (94.1%) and inner(85.3%) portions in consolidated lung than in muscles (p<0.005); the presence of cavity (91.2%, p<0.05) ; cavitywith fluid or air-fluid level (77.4%, p<0.005); pleural enhancement (88.2%, p<0.00003) ; pleural effusion (33.3%,p<0.05); and change in extrapleural tissue (64.7%, p<0.05). CT findings in patients with consolidation-typebronchioloalveolar carcinoma showed lower attenuation in marginal (90.0%) and inner (60.0%) portions ofconsolidated lung than muscles (p<0.005) and of cavity containing air (100%; p<0.005). However, air-bronchogramand CT angiogram signs were not helpful in differentiating the two groups. CONCLUSION: CT can help differentiateconsolidation-type bronchioloalveolar carcinoma and necrotizing pneumonia.

Correlation of CT Findings and Pathologic Nuclear Grading in Renal Cell Carcinoma

PURPOSE: To correlate the CT findings of renal cell carcinomas with nuclear grading in histopathology. MATERIALS AND METHODS: Preoperative CT scans and pathologic nuclear grading of 60 surgically resected renal cell carcinomas in 55 patients were retrospectively and independently reviewed. RESULTS: As nuclear grade increased, renal cell carcinomas were more likely to be of higher stage(92% of nuclear grade III renal cell carcinomas was of stage Ill, all Grade IV tumors were of stage IIIb or higher) and greater size(84% of grade III tumors and 100% of grade IV tumors>5cm in size) at presentation, and appeared more heterogeneous(84% of grade III tumors and 88% of grade IV tumors showed moderate or severe heterogeneity) and less well marginated(84% of grade Ill tumors and 100% of grade IV tumors had irregular or imperceptible margins). CONCLUSION: Small well-marginated homogeneous renal cell carcinomas were either nuclear grade I or II, and were distinguishable from the more aggressive nuclear grade III or IV lesions, which generally displayed irregular margins and greater inhomogeneity.