Diagnostic value of 18F-FDG PET/CT imaging for primary pulmonary lymphoepithelioma-like carcinoma

Objective To assess the diagnostic value of 18F-FDG PET/CT imaging for primary pulmonary lymphoepithelioma-like carcinoma (LELC). Methods A total of 19 patients (10 males, 9 females; average age 56.4 years) with suspected primary pulmonary LELC undergone whole-body 18F-FDG PET/CT and chest contrast CT scan were enrolled in this retrospective study. The SUVmax and uptake patterns of FDG, the histological types and the clinical stages were recorded. Image characteristics of contrast CT and FDG PET/CT were observed, and the diagnostic efficiency was calculated. Two-sample t test and one-way analysis of variance were used to analyze the results. Results The diagnostic sensitivity and specificity of LELC were 12/13 and 4/6 for FDG PET/CT. The SUVmax of LELC lesions was significantly different from that of other lung malignant tumors or lung benign lesions (F=3.67, P<0.05). The lesion had longer diameter, lower CT density, higher SUVmax in stage Ⅳ patients, compared with that in stageⅠ-Ⅲ patients (F=7.01, P<0.05). The significant difference of SUVmax was found between lesions with ring uptake and lesions with other uptake types (3.94±0.67 vs 2.86±0.35; t=4.07, P<0.05). The SUVmax was higher in Schmincke tumors when compared with that in tumors of Regaud subtype(3.61±0.71 vs 2.76±0.29; t=2.99, P<0.05). Conclusion 18F-FDG PET/CT could be an accurate method in differential diagnoses of primary pulmonary LELC. Key words: Carcinoma, non-small cell lung; Pulmonary lymphoepithelioma-like carcinoma; Tomography, emission-computed; Tomography, X-ray computed; Deoxyglucose