ObjectiveTo investigate the association between the baseline 18F-FDG PET/CT SUVmax and histological subtypes of ≤2 cm early peripheral lung adenocarcinoma (cN0).MethodsWe retrospectively reviewed the clinical data of consecutive patients who received baseline 18F-FDG PET/CT and underwent anatomic lung resection for ≤2 cm early peripheral lung adenocarcinoma from 2011 to 2014 in our institute.ResultsA total of 195 patients were enrolled in this study, including 86 males and 109 females, with an average age of 59.96±9.19 years. Twenty-two patients were pathologically confirmed with lymph node metastasis. One hundred and fifty-seven patients were in the subtype group 1, which included lepidic, acinar, and papillary predominant tumors. Thirty-eight patients were in the subtype group 2, which included solid and micropapillary predominant tumors. The 5-year survival rate was 79.0% and 58.0% in the subtype group 1 and subtype group 2, respectively (P=0.006). The median SUVmax was 2.00 (0.30-13.10) and 4.15 (1.20-17.90) in the subtype group 1 and subtype group 2, respectively (P=0.000). Logistic regression suggested that baseline SUVmax≥2.5 was an independent risk factor for the subtype group 2 (OR=6.635, 95%CI 2.510-17.545, P=0.000). The receiver operating characteristic curve suggested that the continuous SUVmax had an moderate predictive value for subtypes (area under the curve was 0.792, 95%CI 0.717-0.866).ConclusionBaseline 18F-FDG PET/CT SUVmax has certain predictive value for histological subtypes of ≤2 cm early peripheral lung adenocarcinoma.