Small bowel tumors are relatively rare, representing only around 5% of all gastrointestinal neoplasms, with a progressively increasing incidence. Currently, there are no established guidelines for diagnostic approaches, screening procedures, or management strategies for small bowel tumors. We present here the case of a patient with a rare type of metastatic tumor of the small bowel originating from primary lung adenocarcinoma who presented with abdominal pain, severe iron-deficiency anemia, and melena. The initial investigations, gastroscopy and colonoscopy, failed to identify the bleeding source. The obscure bleeding source and diagnosis were achieved through power motorized spiral enteroscopy (MSE), which allowed the visualization and biopsy of the tumor. Histopathological examination established the presence of a poorly differentiated non-mucinous adenocarcinoma originating from the lung. This case is reported to provide evidence of the efficiency of MSE in the diagnosis of small bowel tumors, with the method providing higher insertion depth in a reduced amount of time.

OBJECTIVE: Both mesonephric adenocarcinoma (MA) and mesonephric-like adenocarcinoma (MLA) express thyroid transcription factor 1 (TTF1). TTF1 is also considered a highly sensitive and specific diagnostic marker for primary lung adenocarcinoma (PLA). However, distinguishing PLA from pulmonary metastatic MA/MLA (PMM) based on the expression of TTF1 alone can be difficult. This study aimed to investigate the expression of TTF1 and paired box 8 (PAX8) and assess their value in distinguishing PMM from PLA.
METHODS: We reviewed the electronic medical records and pathology slides of eight PMM cases. We conducted immunostaining for TTF1 and PAX8 in 6, 8, and 21 cases of primary MA/MLA, PMM, and PLA, respectively.
RESULTS: Two patients with stage IB uterine MLA developed lung metastases at 5 and 57 months after hysterectomy. Solitary pulmonary nodules were suspected to be primary lung cancer in two patients. Compared to primary tumors, all matched PMMs exhibited reduced TTF1 immunoreactivity. In contrast, the majority of PLAs showed uniform and intense TTF1 expression. All except one PMM exhibited diffuse and strong PAX8 expression, while only one PLA showed focal and weak PAX8 expression.
CONCLUSIONS: Immunostaining for TTF1 and PAX8 can help in distinguishing PMM from PLA in the diagnosis of pulmonary lesions detected in patients with a history of MA/MLA.

UNASSIGNED: Impact of RNA-binding motif protein 10 (RBM10) and programmed death-ligand 1 (PD-L1) on the postoperative prognosis of patients with epidermal growth factor receptor gene mutation (EGFR-Mt) lung adenocarcinoma with pathological lymph node metastasis is still unclear.
UNASSIGNED: Patients who underwent curative surgery for pN1-N2 EGFR-Mt lung adenocarcinoma (n=129) harboring the EGFR exon 19 deletion mutation (Ex19) (n=66) or EGFR exon 21 L858R mutation (Ex21) (n=63) between January 2010 and December 2020 were included in this retrospective study. The prognoses of patients with low/high cytoplasmic RBM10 expression and PD-L1 negativity/positivity based on immunohistochemistry (IHC) of resected specimens were compared using the log-rank test. The effects of RBM10 and PD-L1 expression on overall survival (OS) were examined via multivariable analysis using the Cox proportional hazards regression model. The effects of RBM10 and PD-L1 expression on progression-free survival (PFS) of EGFR-tyrosine kinase inhibitors (TKIs) therapy among patients with recurrent pN1-N2 EGFR-Mt lung adenocarcinoma (n=67) were examined using log-rank tests.
UNASSIGNED: The RBM10 low expression group showed significantly better 5-year OS than the RBM10 high expression group (89.4% vs. 71.5%, P=0.020), and the PD-L1 negative group tended to have longer 5-year OS than the PD-L1 positive group (86.4% vs. 68.4%, P=0.050). Multivariable analysis showed that high RBM10 expression [hazard ratio (HR), 3.12; 95% confidence interval (CI): 1.19-8.17; P=0.021] and PD-L1 positivity (HR, 3.80; 95% CI: 1.64-8.84; P=0.002) were independent poor prognostic factors for OS. PFS of patients with relapse and first-line EGFR-TKI treatment was significantly better in the PD-L1-negative group than in the PD-L1-positive group (34.5 vs. 12.1 months, P=0.045). PFS of patients with Ex21 relapse and first-line EGFR-TKI treatment was significantly better in the RBM10 low expression group than in the RBM10 high expression group (25.5 vs. 13.0 months, P=0.025).
UNASSIGNED: High RBM10 expression and PD-L1 positivity are poor prognostic factors for OS in patients with pN1-N2 EGFR-Mt lung adenocarcinoma after curative surgery. In patients with recurrent pN1-N2 EGFR-Mt lung adenocarcinoma, PD-L1 and RBM10 expression may influence response to EGFR-TKIs.

BACKGROUND: Pathological stage IB-IIIA lung adenocarcinoma with an epidermal growth factor receptor (EGFR) mutation (Mt) has a high recurrence rate even after complete resection. However, there have been few reports on the risk factors for Mt recurrence. This study aimed to analyze the clinicopathological factors related to the relapse-free survival (RFS) of patients with pathological stage IB-IIIA primary lung adenocarcinoma with and without an EGFR mutation.
METHODS: Patients who underwent curative surgery for Mt (n = 208) harboring the EGFR exon 21 L858R point mutation or EGFR exon 19 deletion mutation and EGFR mutation wild-type lung adenocarcinoma (Wt, n = 358) between January 2010 and December 2020 were included. Patients who received adjuvant EGFR-tyrosine kinase inhibitors were excluded. The prognostic factors for RFS were analyzed using a multivariable Cox regression analysis.
RESULTS: The 5-year RFS rates in the Mt and Wt groups were 43.5 and 52.3%, respectively (p = 0.907). Prognostic factors for RFS in the Mt group included smoking history (hazard ratio [HR], 1.49; p = 0.049), blood vessel invasion (HR, 1.84; p = 0.023), and lymph node metastasis (HR, 1.96; p = 0.005). However, adjuvant chemotherapy was not a prognostic factor (HR, 1.02; p = 0.906). In contrast, positron emission tomography (PET) max standardized uptake value (SUV) ≥ 6.0 (HR, 1.53; p = 0.042), lymphatic vessel invasion (HR, 1.54; p = 0.036), lymph node metastasis (HR, 1.79; p = 0.002), and adjuvant chemotherapy (HR, 0.60; p = 0.008) were prognostic factors for RFS in the Wt group.
CONCLUSIONS: Prognostic factors for RFS in stage IB-IIIA primary lung adenocarcinoma differ by epidermal growth factor receptor mutation status. The impact of adjuvant chemotherapy on RFS also differed by EGFR mutation status.

The clinical data for a patient with primary lung adenocarcinoma complicated with pulmonary hamartoma, who admitted to Zunyi Medical University Hospital in September 2020, was retrospectively analyzed. The 62-years-old male visited outpatient service because of dysphagia in March 2015, and the pulmonary nodules were found. In September 2020, the computed tomography indicated the enlarged nodule in the lower lobe of left lung with lobulation, and there was ground glass nodule in the upper lobe of left lung. After thoracoscopic wedge surgery, the primary pulmonary adenocarcinoma in the upper lobe of left lung and pulmonary hamartoma in the lower lobe of left lung were confirmed by pathology. Whole exon sequencing revealed that kinesin family member 20B (KIF20B) gene was not expressed in lung adenocarcinoma, but was expressed in pulmonary hamartoma. The clinical manifestations of lung adenocarcinoma complicated with pulmonary hamartoma was not typical, which could locate in the same side and different sides of the lung. The imaging manifestations of the 2 kinds of tumors were diverse and can not be completely distinguished. The pathological examination after surgery is the gold standard, and the possibility of malignant transformation of pulmonary hamartoma should be warned.
遵义医科大学附属医院于2020年9月收治的原发性肺腺癌合并肺错构瘤患者1例，男，62岁，以吞咽困难就诊。2015年3月发现肺结节于门诊规律随访，2020年9月胸部CT显示左肺下叶结节增大、有分叶，左肺上叶有磨玻璃结节影，行胸腔镜下楔形手术，术后病理确诊为左肺上叶原发性肺腺癌、左肺下叶肺错构瘤。全外显子组测序发现驱动蛋白20(kinesin family member 20B，KIF20B)基因在肺腺癌中无表达，在肺错构瘤中有表达。肺腺癌合并肺错构瘤的临床表现不典型，可位于同侧及对侧肺叶，两者影像学表现多样，不能完全区分，手术后的病理学检查是金标准，需警惕肺错构瘤恶变的可能。.

Calcification in a lung tumor suggests that it is a benign tumor such as a hamartoma or a sclerosing lung cell tumor. In contrast, carcinoid, lung cancer, carcinosarcoma, and sarcoma rarely harbor calcification. Primary lung adenocarcinomas with gross calcification that is suggestive of bone formation are very rare. It is difficult to distinguish between calcification and bone formation purely on the basis of image definitive diagnosis of bone formation being difficult in the absence of a large surgical specimen. Lung cancers with bone formation are exceedingly rare: to the best of our knowledge, only 13 cases have been reported. Careful attention is needed when differentiating between benign and malignant tumors. Here, we report a case of primary lung adenocarcinoma with gross calcification that was suggestive of bone formation.

OBJECTIVE: To explore the effect of smoking on the histological subtype and prognosis of patients with lung adenocarcinoma (LAC) in China.
METHODS: According to the new International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society(IASLC/ATS/ERS)classification, 266 donors with primary LAC were reclassified. The correlation between clinicopathological factors including smoking status and the histological subtype was analyzed, and survival analysis was used to analyze the prognosis of primary LAC.
RESULTS: There were four main histological subtypes including acinar predominant adenocarcinoma (APA) 30.1%, papillary predominant adenocarcinoma (PPA) 26.7%, solid predominant adenocarcinoma (SPA) 25.9%, and lepidic predominant adenocarcinoma (LPA) 11.7%.Smoking was associated with the histological subtype.The proportion of smokers was significantly higher than non-smokers in the SPA group, and the proportion of non-smokers was higher in other subtypes group. Cox regression model showed that the histological subtype and TNM stage were the independent predictors of prognostic in all patients.TNM stage was the predictor of postoperative survival in both smokers and non-smokers, and histological subtypes was the predictor only in smokers (β=0.898, RR=2.455). Compared with the non-SPA group, the prognosis of the SPA group was significantly worse.
CONCLUSIONS: Smoking is associated with SPA subtype, which affect the prognosis of primary LAC.

BACKGROUND: Arginase-1 is a novel immunohistochemical (IHC) marker for hepatocellular differentiation. The purpose of this study was to evaluate the expression of Arginase-1 and HepPar-1 in lung adenocarcinoma to assess the potential value of these markers for diagnosing metastatic lung tumors, especially to the liver in fine-needle aspiration specimens.
METHODS: Forty-four cytology specimens of lung adenocarcinoma, obtained by endobronchial ultrasound-guided fine-needle aspiration were retrospectively reviewed. IHC stains for Arginase-1 and HepPar-1 were performed on formalin-fixed paraffin-embedded cell blocks. Tissue from confirmed hepatocellular carcinoma was used as the positive control. TTF-1 IHC stain was performed in all cases.
RESULTS: All 44 lung adenocarcinoma cases (100%) were negative for Arginase-1, whereas HepPar-1 expression was detected in 3 (7%) of lung adenocarcinomas and negative in 41 (93%). The 3 HepPar-1-positive lung adenocarcinoma cases demonstrated positive TTF-1 IHC stain performed on the same cell block. Although both Arginase-1 and HepPar-1 are useful diagnostic IHC markers to differentiate metastatic lung adenocarcinoma from hepatocellular carcinoma, Arginase-1 IHC stain shows better specificity than HepPar-1 does (Arginase-1 specificity 100% and HepPar-1 specificity 93%).
CONCLUSIONS: Arginase-1 IHC can be used in combination with other markers in the workup of metastatic lung adenocarcinoma, especially to the liver.

BACKGROUND: It is crucial to develop novel diagnostic approaches for determining if peripheral lung nodules are malignant, as such nodules are frequently detected due to the increased use of chest computed tomography scans. To this end, we evaluated levels of napsin A in epithelial lining fluid (ELF), since napsin A has been reported to be an immunohistochemical biomarker for histological diagnosis of primary lung adenocarcinoma.
METHODS: In consecutive patients with indeterminate peripheral lung nodules, ELF samples were obtained using a bronchoscopic microsampling (BMS) technique. The levels of napsin A and carcinoembryonic antigen (CEA) in ELF at the nodule site were compared with those at the contralateral site. A final diagnosis of primary lung adenocarcinoma was established by surgical resection.
RESULTS: We performed BMS in 43 consecutive patients. Among patients with primary lung adenocarcinoma, the napsin A levels in ELF at the nodule site were markedly higher than those at the contralateral site, while there were no significant differences in CEA levels. Furthermore, in 18 patients who were undiagnosed by bronchoscopy and finally diagnosed by surgery, the napsin A levels in ELF at the nodule site were identically significantly higher than those at the contralateral site. In patients with non-adenocarcinoma, there were no differences in napsin A levels in ELF. The area under the receiver operator characteristic curve for identifying primary lung adenocarcinoma was 0.840 for napsin A and 0.542 for CEA.
CONCLUSIONS: Evaluation of napsin A levels in ELF may be useful for distinguishing primary lung adenocarcinoma.

The characteristic radiological signs of primary lung adenocarcinoma include notching, lobulation, spicular formation, pleural indentation and a bronchus leading to the nodule (bronchus sign). However, metastatic tumors rarely display such characteristics. We herein present two cases of breast cancer with sole metastatic pulmonary tumors recurring ~20 years after surgery for breast cancer. These patients exhibited radiographic signs specific to primary lung adenocarcinoma. Pulmonary metastatic nodular lesions occur through hematogenous spread; therefore, obtaining pathological specimens by transbronchial biopsy may be challenging. In our patients, however, obtaining pathological specimens by transbronchial biopsy was feasible and it ultimately confirmed the diagnosis of lung metastasis from previously treated breast cancer. To the best of our knowledge, no similar cases are reported in the English medical literature. Therefore, metastatic breast cancer may exhibit the characteristic radiological signs of pulmonary lung adenocarcinoma and, although rare, pulmonary metastasis from breast cancer should be considered even in the presence of irregularly shaped pulmonary nodule(s) following long-term disease-free survival.