Predicting pathological highly invasive lung cancer from preoperative [18F]FDG PET/CT with multiple machine learning models.

PURPOSE: The efficacy of sublobar resection of primary lung cancer have been proven in recent years. However, sublobar resection for highly invasive lung cancer increases local recurrence. We developed and validated multiple machine learning models predicting pathological invasiveness of lung cancer based on preoperative [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) radiomic features. METHODS: Overall, 873 patients who underwent lobectomy or segmentectomy for primary lung cancer were enrolled. Radiomics features were extracted from preoperative PET/CT images with the PyRadiomics package. Seven machine learning models and an ensemble of all models (ENS) were evaluated after 100 iterations. In addition, the probability of highly invasive lung cancer was calculated in a nested cross-validation to assess the calibration plot and clinical usefulness and to compare to consolidation tumour ratio (CTR) on CT images, one of the generally used diagnostic criteria. RESULTS: In the training set, when PET and CT features were combined, all models achieved an area under the curve (AUC) of ≥ 0.880. In the test set, ENS showed the highest mean AUC of 0.880 and smallest standard deviation of 0.0165, and when the cutoff was 0.5, accuracy of 0.804, F1 of 0.851, precision of 0.821, and recall of 0.885. In the nested cross-validation, the AUC of 0.882 (95% CI: 0.860-0.905) showed a high discriminative ability, and the calibration plot indicated consistency with a Brier score of 0.131. A decision curve analysis showed that the ENS was valid with a threshold probability ranging from 3 to 98%. Accuracy showed an improvement of more than 8% over the CTR. CONCLUSION: The machine learning model based on preoperative [18F]FDG PET/CT images was able to predict pathological highly invasive lung cancer with high discriminative ability and stability. The calibration plot showed good consistency, suggesting its usefulness in quantitative risk assessment.

Randomized controlled phase III trial of adjuvant chemoimmunotherapy with activated cytotoxic T cells and dendritic cells from regional lymph nodes of patients with lung cancer.

Randomized controlled trial of adjuvant chemoimmunotherapy for lung cancer indicated a significant advantage in patients receiving immunotherapy. Herein we report the final results and immunological analysis with a median follow-up of 59.6 months. Patients with post-surgical lung cancer were randomly designated to receive either chemoimmunotherapy (group A, immunotherapy arm) or chemotherapy (group B, control arm). The immunotherapy comprised the adoptive transfer of autologous activated killer T cells and dendritic cells (AKT-DC). The 2- and 5-year overall survival (OS) rates were 96.0 and 69.4% in group A and 64.7 and 45.1% in group B, respectively. Multivariate analysis results revealed that the hazard ratio was 0.439. The 2- and 5-year recurrence-free survival rates were 70.0 and 57.9% in group A and 43.1 and 31.4% in group B, respectively. Subgroup analysis for the OS between treatment groups indicated that younger patients (≤ 55 years: HR 0.098), males (HR 0.474), patients with adenocarcinoma (HR 0.479), patients with stage III cancer (HR 0.399), and those who did not receive preoperative chemotherapy (HR 0.483) had lower HRs than those in the other groups. Immunological analysis of cell surface markers in regional lymph nodes of subjects receiving immunotherapy indicated that the CD8+/CD4+ T-cell ratio was elevated in survivors. Patients with non-small-cell lung cancer benefited from adoptive cellular immunotherapy as an adjuvant to surgery. Patients with stage III cancer, those with adenocarcinoma, and those not receiving preoperative chemotherapy were good candidates. Lastly, cytotoxic T cells were important for a favorable chemoimmunotherapy outcome.

Randomized controlled phase III trial of adjuvant chemo-immunotherapy with activated killer T cells and dendritic cells in patients with resected primary lung cancer.

PURPOSE: We conducted a phase III randomized controlled trial (RCT) to investigate the efficacy of postsurgical adjuvant immunotherapy combined with chemotherapy. The immunotherapy targets were residual micrometastases and clones resistant to chemotherapy. PATIENTS AND METHODS: Between April 2007 and July 2012, 103 postsurgical non-small cell lung cancer patients were randomly assigned to receive either chemo-immunotherapy (group A) or chemotherapy (group B). The immunotherapy consisted of the adoptive transfer of autologous activated killer T cells and dendritic cells obtained from the lung cancer patients' own regional lymph nodes. RESULTS: The 2-year overall survival rates in groups A and B were 93.4 and 66.0 %, and the 5-year rates were 81.4 and 48.3 %, respectively. The differences were statistically significantly better in group A. The hazard ratio (HR) was 0.229 (p = 0.0013). The 2- and 5-year recurrence-free survival rates were 68.5, 41.4 and 56.8, 26.2 % in groups A and B, respectively. Those differences were also statistically significant (log-rank test p = 0.0020). The HR was 0.423 (p = 0.0027) in favor of group A. As for adverse reactions to immunotherapy, of a total of 762 courses, 52 (6.8 %) were accompanied with chills and shivering, and 47 (6.2 %), with fever (>38 °C). CONCLUSIONS: Immunotherapy has the potential to improve the postsurgical prognosis of lung cancer patients, but a large-scale multi-institutional RCT is awaited for further confirmation of this study.

Can modified frailty index predict postoperative complication after lung cancer surgery?

PURPOSE: The impact of the modified frailty index (mFI) on postoperative complications after lung cancer surgery was investigated. METHODS: Patients who underwent lung cancer surgery in 2017 were included. 30-day postoperative mortality and morbidity were evaluated according to their Clavien-Dindo classification. mFI values are presented as the sum of values of 11 included items. Logistic regression was used to assess the effect of mFI on postoperative severe complication incidence. RESULTS: Among 190 patients considered, severe postoperative complications (Grade 3 or more) were observed in 30 (16%). No patients died within 30 days of surgery. The incidence of severe complications was 3.6% in patients with mFI of 0, 16.2% in patients with mFI of 1, 23.4% in patients with mFI of 2, and 31.6% in patients with mFI of 3 or more, and was correlated with the grade of mFI. Univariate and multivariate analyses showed that the high mFI was significantly predictive of postoperative complications. Frail patients of mFI ≥ 2 were at 3.0-fold greater risk of severe complications than non-frail patients of mFI 0 or 1. CONCLUSION: mFI was associated with morbidity after lung cancer surgery. Preoperative frailty assessment and appropriate intervention to frail patients would be required to improve postoperative outcomes.

What are the risk factors for postoperative home oxygen therapy in patients with lung cancer?

Background: Home oxygen therapy (HOT) is used to treat chronic respiratory diseases and is sometimes required in patients with lung cancer after radical surgery. We aimed to identify the risk factors for postoperative home-based oxygen therapy in patients with lung cancer. Methods: Patients who underwent surgery for primary lung cancer at Chiba University Hospital between January 2019 and March 2021 were included. Patients who did not undergo complete resection, died in hospital after surgery, or used oxygen therapy preoperatively were excluded. Eligible patients were divided into HOT and non-HOT groups. They were retrospectively analyzed for risk factors for postoperative HOT using medical records in a multivariate analysis. Results: A total of 410 patients were included in this study, 24 (5.9%) of whom required HOT after surgery. The HOT group comprised significantly more men, heavy smokers, and patients with pulmonary comorbidities, low percent forced expiratory volume, percent forced vital capacity, predicted postoperative forced expiratory volume in 1 s, and postoperative pulmonary complications on univariate analysis. In a multivariate analysis, independent risk factors for postoperative HOT were pulmonary comorbidities [odds ratio (OR): 5.94; 95% confidence interval (CI): 1.64-21.5; P=0.002) and postoperative pulmonary complications (OR: 5.39; 95% CI: 2.14-13.5; P<0.001). The postoperative HOT application rate was calculated according to a formula developed for this purpose. Conclusions: Comorbid pulmonary diseases and postoperative pulmonary complications were significantly associated with postoperative HOT in patients with lung cancer.

Improvement of Lithium-Sulfur Battery Performance by Porous Carbon Selection and LiFSI/DME Electrolyte Optimization.

High-concentration lithium bis(fluorosulfonyl)imide/1,2-dimethoxyethane (LiFSI/DME) electrolytes are promising candidates for highly reversible lithium-metal anodes. However, the performance of lithium-sulfur (Li-S) batteries with a high concentration of LiFSI/DME declines because LiFSI reacts irreversibly with lithium polysulfide, which is formed during the charge-discharge process of Li-S batteries. Hence, to apply high-concentration LiFSI/DME to Li-S batteries, we investigated carbon with an appropriate pore size for use in a sulfur composite cathode and optimized the composition of high-concentration LiFSI/DME. The results showed that the combination of carbon with mesopores of 2-3 nm diameter and 3 M LiFSI in DME/1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropylether (HFE) (1:1 by vol.) provided a high-rate capability (943 mA h g-1 at a rate of 2 C). Moreover, the ratio of the 50th discharge capacity to the 2nd discharge capacity (capacity retention) improved from 50.0 to 61.6% with HFE dilution of high-concentration LiFSI/DME. The improved performance was achieved by suppressing the dissolution of lithium polysulfide, decreasing the viscosity of the electrolyte, and forming a thin solid electrolyte interface on the lithium-metal anode due to HFE dilution.

Production of both IL-27 and IFN-gamma after the treatment with a ligand for invariant NK T cells is responsible for the suppression of Th2 response and allergic inflammation in a mouse experimental asthma model.

Using an allergen-induced airway inflammation model, we show that an injection of alpha-galactosylceramide (alpha-GalCer), a ligand for invariant NK T (iNKT) cells, induced IL-27 and that this process is essential for the attenuation of the Th2 response. After the systemic administration of alpha-GalCer into the mice primed with OVA in alum, Th2 cytokine production of OVA-primed CD4(+) T cells in their lymph nodes, IgG1 and IgE Ab formation, and infiltration of eosinophils in bronchoalveolar lavage after the OVA challenge were suppressed. Systemic administration of rIFN-gamma into OVA-primed mice could not reproduce these effects of alpha-GalCer. IL-27p28 was detected both in the culture supernatant of alpha-GalCer-stimulated spleen cells and in the serum of the alpha-GalCer-treated mice, but not in the iNKT cell-deficient mice. Splenic iNKT cells produced IL-27p28 in the culture supernatant upon stimulation with PMA plus ionomycin, although the transcript of IL-27p28 in the iNKT cells was constitutively expressed regardless of the stimulation. By contrast, the transcript of IL-27EBI3 was induced in the iNKT cells upon stimulation with PMA plus ionomycin in vitro and with alpha-GalCer treatment in vivo, suggesting that IL-27 (p28/EBI3) could be produced by iNKT cells in an activation-dependent manner. Although repeated injections of rIL-27 did not substitute for the effects of a single injection of alpha-GalCer, administration of rIL-27 along with rIFN-gamma reproduced in vivo effects of the alpha-GalCer injection. These data indicate that production of both IL-27 and IFN-gamma by the alpha-GalCer treatment is responsible for suppression of the Th2 response and allergic inflammation.

Comparison of 21-gauge and 22-gauge aspiration needle during endobronchial ultrasound-guided transbronchial needle aspiration.

BACKGROUND AND OBJECTIVE: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has typically been performed using the 22 gauge (G) dedicated TBNA needle. Recently a new 21G TBNA needle has been introduced. The efficacy of using a larger gauge biopsy needle during EBUS-TBNA has not been reported. The purpose of this study was to compare the diagnostic yield and utility of 21G and 22G needles during EBUS-TBNA. METHODS: EBUS-TBNA was performed using both 21G and 22G needles. Cytological and histological findings were recorded for each samples obtained by an independent cytologist and pathologist. The cellularity and blood contamination were evaluated in the cytological samples. The quality of the histological core was evaluated by the amount of blood clots versus the actual tissue. Each factor was compared within two slides from the two different size needles. The diagnostic yield and the differences of the cytology and histology were analysed. RESULTS: The evaluation of 45 lesions by EBUS-TBNA revealed that tumour cells were equally detected by both 21G and 22G needles. Two patients of adenocarcinoma were histologically diagnosed only by the 21G needle. Although histological structure was better preserved in five lesions collected by the 21G needle, there was more blood contamination with the 21G needle (P < 0.0001). CONCLUSIONS: There were no differences in the diagnostic yield between the 21G and 22G needles during EBUS-TBNA. The preserved histological structure of the samples obtained by the 21G needle may be useful for the diagnosis of mediastinal and hilar adenopathy of unknown aetiology which may be a challenge with the 22G needle.

Age estimation using methylation-sensitive high-resolution melting (MS-HRM) in both healthy felines and those with chronic kidney disease.

Age is an important ecological tool in wildlife conservation. However, it is difficult to estimate in most animals, including felines-most of whom are endangered. Here, we developed the first DNA methylation-based age-estimation technique-as an alternative to current age-estimation methods-for two feline species that share a relatively long genetic distance with each other: domestic cat (Felis catus; 79 blood samples) and an endangered Panthera, the snow leopard (Panthera uncia; 11 blood samples). We measured the methylation rates of two gene regions using methylation-sensitive high-resolution melting (MS-HRM). Domestic cat age was estimated with a mean absolute deviation (MAD) of 3.83 years. Health conditions influenced accuracy of the model. Specifically, the models built on cats with chronic kidney disease (CKD) had lower accuracy than those built on healthy cats. The snow leopard-specific model (i.e. the model that resets the model settings for snow leopards) had a better accuracy (MAD = 2.10 years) than that obtained on using the domestic cat model directly. This implies that our markers could be utilised across species, although changing the model settings when targeting different species could lead to better estimation accuracy. The snow leopard-specific model also successfully distinguished between sexually immature and mature individuals.

Operando soft X-ray absorption spectroscopic study on microporous carbon-supported sulfur cathodes.

Sulfur is a promising material for next-generation cathodes, owing to its high energy and low cost. However, sulfur cathodes have the disadvantage of serious cyclability issues due to the dissolution of polysulfides that form as intermediate products during discharge/charge cycling. Filling sulfur into the micropores of porous carbon is an effective method to suppress its dissolution. Although microporous carbon-supported sulfur cathodes show an electrochemical behavior different from that of the conventional sulfur ones, the corresponding reaction mechanism is not clearly understood. In this study, we focused on clarifying the reaction mechanism of microporous carbon-supported sulfur cathodes by operando soft X-ray absorption spectroscopy. In the microporous carbon support, sulfur was present as smaller fragments compared to conventional sulfur. During the first discharge process, the sulfur species in the microporous carbon were initially reduced to S6 2- and S2 2- and then to Li2S. The S6 2- and S2 2- species were observed first, with S2 2- being the main polysulfide species during the discharge process, while Li2S was produced in the final discharge process. The narrow pores of microporous carbon prevent the dissolution of polysulfides and influence the reaction mechanism of sulfur cathodes.

A surgical case of synchronous solitary splenic metastasis from lung squamous cell carcinoma: report of a case and review of the literature.

Solitary splenic metastasis is an extremely rare event. We herein report a surgical case of a solitary splenic metastasis from lung cancer. A 78-year-old man presented with abdominal pain. Abdominal computed tomography (CT) showed splenic rupture. Coil embolization to the splenic artery was performed, and the patient's condition improved. Chest CT showed a 5-cm lung mass in the right upper lobe, suggesting lung cancer with splenic metastasis. Transbronchial aspiration cytology showed squamous cell carcinoma of the lung. We diagnosed the patient with lung cancer (cT2bN0M1b [spleen only] stage IVA) and performed splenectomy and right upper lobectomy separately. Both lesions were squamous cell carcinoma and positive for p40. Thus, primary lung squamous cell carcinoma and solitary splenic metastasis were diagnosed. The patient was still alive without recurrence 15 months postoperatively. We herein report a rare case of lung squamous cell carcinoma with solitary splenic metastasis and review the literature.

The relationship between plant-eating and hair evacuation in snow leopards (Panthera uncia).

Although most felids have an exclusive carnivore diet, the presence of plant matter in scat has been reported among various species. This indicates that there may be an adaptive significance to the conservation of plant-eating behavior in felid evolution. Some studies have hypothesized that felids consume plants for self-medication or as a source of nutrition. In addition, it is thought that plant intake helps them to excrete hairballs, however, no scientific work has confirmed these effects. Thus, the objective of this study is to investigate the relationship between plant intake and hair evacuation in felid species. We selected snow leopards (Panthera uncia) as the study species because they have longer and denser hair than other felids. The behavior of 11 captive snow leopards was observed and scat samples from eight of them and two other captive individuals were analyzed. Snow leopards evacuate hair possibly by vomiting and excreting in scats. The frequency of plant-eating and vomiting and the amount of hair and plant in scat were evaluated. We found that the frequency of vomiting was much lower than the frequency of plant-eating. In addition, there was no significant relationship between the amount of plant matter contained in scats and the amount of hair in scats. Contrary to the common assumption, our results indicate that plant intake has little effect on hair evacuation in felid species.

A strategy for pulmonary resection after contralateral diaphragm plication: a surgical case report.

BACKGROUND: Pulmonary carcinoma patients with low pulmonary function cannot be treated surgically because of the high risk of complications. Diaphragmatic eventration is a disease characterized by diaphragmatic paralysis and dyspnea. Here, we report a surgical case of multiple pulmonary carcinomas with contralateral diaphragmatic eventration. CASE PRESENTATION: The patient was a 75-year-old woman with multiple metachronous right lung carcinomas complicated by left diaphragmatic eventration. When she was 70 years old, a right upper lobectomy and right S6b wedge resection were performed for double lung carcinomas. Five years later, two new lung tumors in her right lower lobe and left diaphragmatic eventration were identified, but resection was thought to be impossible because of her low pulmonary function. We performed video-assisted thoracoscopic surgery (VATS) plication with carbon dioxide (CO2) insufflation for the left diaphragmatic eventration, and her pulmonary function improved. Subsequently, we performed a right S6 wedge resection and right S9 segmentectomy for the double lung tumors with no complications. The tumors were diagnosed as double primary carcinomas. CONCLUSIONS: Our case presented with low pulmonary function and right multiple lung carcinomas with left diaphragmatic eventration. VATS plication for the left diaphragmatic eventration achieved improvement in her pulmonary function, and right pulmonary resection for the lung carcinomas was performed. VATS plication can expand the choice of treatments in such cases.

A case of primary pulmonary leiomyosarcoma completely resected after neoadjuvant chemotherapy.

BACKGROUND: Primary pulmonary leiomyosarcoma is a rare malignant tumor. We herein report a case of primary pulmonary leiomyosarcoma that was completely resected by surgery after neoadjuvant chemotherapy. CASE PRESENTATION: A 60-year-old man presented with cough. Chest computed tomography showed an 11-cm mass in the right upper lobe of the lung that had invaded the superior vena cava. Endobronchial ultrasound-guided transbronchial needle aspiration revealed leiomyosarcoma of the lung. We considered complete resection of the tumor to be very difficult because of the tumor invasion into the right atrium inflow of the superior vena cava, so we performed chemotherapy using doxorubicin for five cycles. After chemotherapy, the tumor size decreased to 5.6 cm, and we performed right upper lobectomy with combined resection of the superior vena cava. The tumor was completely resected by surgery. The patient is alive without recurrence 17 months postoperatively. CONCLUSIONS: We encountered a case of primary pulmonary leiomyosarcoma that was successfully treated by surgery after neoadjuvant chemotherapy. Doxorubicin monotherapy was effective in this case. Surgery combined with neoadjuvant chemotherapy should be considered for such cases, as a long-term survival can be achieved by complete resection of primary pulmonary leiomyosarcoma.

Clinicopathological outline of dementia with Lewy bodies applying the revised criteria: the Hisayama study.

To explore the validity of the criteria for dementia with Lewy bodies (DLB) revised in 2005, we examined community based consecutive autopsy cases. 10.3% of the non-demented subjects and 31.2% of the demented subjects showed the Lewy body pathology. Applying the revised pathological criteria to the 205 demented subjects, the types of LB pathology of 11 cases (5.4%) were brainstem-predominant, 24 cases (11.7%) were limbic type and 24 cases (11.7%) were diffuse neocortical type, although there were many subjects not to fit the criteria exactly. The prevalence of Lewy bodies (LBs) was almost same regardless of gender; however, the extent of the LB pathology among females was more severe than that in males. The likelihood of DLB being modified by concomitant Alzheimer's pathology was as follows: 27 cases (13.2%) showed low likelihood, 16 cases (7.8%) showed intermediate likelihood and 16 cases (7.8%) showed high likelihood. Since the numbers of clinical features of DLB were significantly higher in the pathological intermediate and high likelihood DLB groups than in the low likelihood DLB group or no LB group, both the intermediate and high likelihood groups of DLB should be considered as pathological DLB.

Characterization of the immature dendritic cells and cytotoxic cells both expanded after activation of invariant NKT cells with alpha-galactosylceramide in vivo.

Invariant natural killer T (iNKT) cells can perform multiple functions characteristic of both innate and acquired immunity. Activation of iNKT cells in vivo by repeated alpha-GalCer injections can induce immune tolerance, but the mechanisms responsible for such immunoregulation remain unclear. We prepared alpha-GalCer-liposomes, a single injection of which into mice resulted in the expansion of splenic CD11c(low)CD45RB(high) cells, which consists of two populations, CD180(+) and CD49b(+). Expansion of these cells was not observed in alpha-GalCer-liposome-treated mice deficient in IL-10 or iNKT cells. MHC and co-stimulatory molecules were down-regulated in CD11c(low)CD180(+) cells compared with conventional dendritic cells (cDCs), suggesting that the former possess characteristics of immature DCs. Meanwhile, the CD11c(low)CD49b(+) cells expressed IL-10 and Ctla4, and possessed greater lytic activity than resting NK cells. These observations suggest that both immature DCs (CD11c(low)CD180(+)) and cytotoxic cells (CD11c(low)CD49b(+)) might be expanded by alpha-GalCer-activated iNKT cells and could therefore be involved in immune tolerance.

Alpha-galactosylceramide-driven immunotherapy for allergy.

We report here that the delivery of both alpha-galactosylceramide (alphaGalCer), a representative ligand for invariant natural killer T (iNKT) cells, and an antigenic polypeptide to marginal zone B cells induces the differentiation of regulatory cells in vivo, and suppresses the secondary antibody responses in mice. Splenic CD21+ CD23- B cells of mice treated with alphaGalCer-liposomes produce IL-10 when co-cultured with iNKT cells, whereas the cells treated with aqueous alphaGalCer fail to do so. Adoptive transfer of the B cells into syngenic mice leads to the expansion of splenic CD11c(low) CD45RB(high) cells, which convert naive CD4+ T cells from RAG2-deficient DO11.10 mice to CD4+ CD25(high) Foxp3+ T cells in the presence of OVA323-339 peptide. Administration of alphaGalCer-OVA-liposomes into OVA-primed mice causes the development of CD4+ CD25(high) Foxp3+ T cells that produce both IL-10 and IFN-gamma, and induced the antigen-specific suppression of the secondary antibody responses when boosted with OVA alone. These results indicate that antigen-containing alphaGalCer-liposomes can facilitate the development of tolerogenic antigen-presenting cells and inducible regulatory T cells that are involved in the suppression of immune responses to antigens.

Involvement of Na+/Ca2+ exchanger type-1 in ischemia-induced neovascularization in the mouse hindlimb.

The Na+/Ca2+ exchanger (NCX) is considered to be involved in endothelial nitric oxide (NO) production and endothelium-dependent vasorelaxation, but little is known about the physiological and pathological roles of endothelial NCX in these processes. We examined the role of NCX1 in neovascularization in mice with hindlimb ischemia. Unilateral hindlimb ischemia was induced surgically in wild-type and heterozygous NCX1 knockout mice (NCX1+/-) mice. We found that in NCX1+/- mice, blood flow recovery was significantly augmented compared with that in wild-type mice. N(G)-nitro-L-arginine methyl ester treatment eliminated enhanced angiogenesis observed in NCX1+/- mice. These results suggest that NCX1 is involved in eNOS-dependent angiogenesis.

Differential diagnosis of primary intrapulmonary thymoma: a report of two cases.

Primary intrapulmonary thymomas (PITs), which are intrapulmonary tumors without an associated mediastinal component, are very rare. The diagnosis of a PIT can be difficult. Here, we report two cases of resected PITs that were difficult to differentiate from other lung tumors. The patients, of a 62-year-old man and a 64-year-old woman, had no significant symptoms and were both referred to our hospital due to the presence of an abnormal shadow on chest computed tomography (CT). The patients underwent (18)F-fluorodeoxyglucose positron emission tomography-CT (FDG-PET/CT) and subsequently tumor excision. A PIT was confirmed histopathologically in the surgical specimens from both patients. In one case, the tumor consisted of a type A thymoma without abnormal FDG uptake. In the other case, the tumor consisted of a type B2 thymoma presenting with weak FDG uptake. This report thus documents two cases of PITs with different histopathologic and FDG-PET/CT findings. Thoracoscopic surgery is essential in the differential diagnosis between PITs and other lung tumors.