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.

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。.