PurposeThe purpose of this study was to evaluate the correlation between histological invasiveness and the computed tomography (CT) value and size in pure ground-glass nodules (GGNs) to determine optimal “follow-up or resection” strategies.MethodsBetween 2001 and 2014, 78 resected, pure GGNs were retrospectively evaluated. The maximum diameter and CT value of pure GGNs were measured using a computer graphics support system.ResultsAll GGNs with a maximum diameter ≤10 mm and CT value ≤−600 Hounsfield units (HU) were considered to be noninvasive lesions, while 21 of 26 (81 %) with a maximum diameter >10 mm and CT value >−600 HU were considered to be invasive lesions. With respect to the correlation between each histological type and pure GGN with a maximum diameter ≤10 mm and CT value ≤−600 HU, the specificity was 90 % and the sensitivity and negative predictive value were both 100 % in atypical adenomatous hyperplasia (AAH), while the specificity was 58 % and the sensitivity and positive predictive value were 0 % in minimally invasive and invasive adenocarcinoma.ConclusionPure GGNs with a maximum diameter of ≤10 mm and CT value of ≤−600 HU are nearly always pre-invasive lesions; therefore, surgery should be carefully selected in such patients.

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Based on the results of this study and the literature review, we feel that a positive response is obtainable with chemotherapy for thymic carcinoma. Modified ADOC therapy showed consistent efficacy in thymic carcinoma in this study.

Therefore, by examining the expressions of PPARγ and IGF1R, it would be possible to identify therapy-responsive patients and to improve results of thymic carcinoma treatment.

BackgroundIn a number of human malignancies, tumor-associated macrophages (TAMs) are closely involved in tumor progression. On the other hand, dendritic cells (DCs) that infiltrate tumor tissues are involved in tumor suppression. However, there have been very few reports on the distribution profiles of TAMs and DCs in thymic epithelial tumors. We examined the difference in the distribution profiles between TAMs and DCs in thymoma and thymic carcinoma.MethodsWe examined 69 samples of surgically resected thymic epithelial tumors, namely, 16 thymic carcinomas and 53 thymomas, in which we immunohistochemically evaluated the presence of TAMs using CD68 and CD163 as markers and DCs using S100 as the marker in tumor tissue samples in comparison with normal thymic tissues.ResultsThe percentage of samples with a large number of CD68+ TAMs was not significantly different between thymic carcinoma and thymoma (7/16 versus 16/53, p = 0.904). However, the percentage of sample with a large number of CD163+ TAMs was significantly higher in thymic carcinoma than in thymoma (15/16 versus 34/53, p = 0.024). In contrast, the percentage of samples with a large number of S100+ DCs was significantly lower in thymic carcinoma than in thymoma (2/16 versus 23/53, p = 0.021).ConclusionsTo the best of our knowledge, we are the first to show a high percentage of CD163+ TAMs and a low percentage of S100+ DCs in thymic carcinoma samples, and our findings may provide an idea for future targeted therapeutic strategies for thymic carcinoma using antibodies that inhibit monocyte differentiation to TAMs, thereby skewing TAMs differentiation toward DCs.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_215