Characteristic computed tomography features in mesenchymal-epithelial transition exon14 skipping-positive non-small cell lung cancer.

BACKGROUND: Mesenchymal-epithelial transition exon14 (METex14) skipping is one of the therapeutic driver oncogene mutations in non-small cell lung cancer (NSCLC), and can be treated with tepotinib and capmatinib. There is only one report on computed tomography (CT) findings of METex14 skipping-positive NSCLC, which shows that the primary tumor tends to have a large mass in the upper lobe, and extrathoracic metastases are common. This study examined the CT findings of METex14 skipping-positive NSCLC, focusing on the features of the margins and internal structures. METHODS: We consecutively included patients with METex14 skipping-positive NSCLC who were diagnosed between January 2018 and December 2020 at four independent institutions. We retrospectively reviewed the patient demographics and CT findings for tumor margins (invasion into surrounding tissue, lobulation, pleural indentation, spicula, and ground-glass opacity) and internal structures (air bronchograms, cavitation and internal low-density area). RESULTS: Fifteen patients with METex14 skipping-positive NSCLC were identified. Almost half of the patients were men (7/15; 46.7%), and their median age was 75.0 years. More than half were either current or former smokers (9/15; 60.0%). A vast majority of histological subtypes were adenocarcinoma (10/15; 66.7%), followed by pleomorphic carcinoma (3/15; 20.0%) and squamous cell carcinoma (2/15; 13.3%). With regard to CT findings, most primary tumors presented as masses larger than 30 mm (12/15; 80.0%) and were located in the upper lobes (12/15; 80.0%). Invasion into surrounding tissue and presence of internal low-density areas were observed in 60.0% (9/15) and 66.7% (10/15) of the primary tumors, respectively. Additionally, their frequencies increased to 72.7% (8/11) and 90.9% (10/11) in stage III/IV cases, respectively. In lymph node metastasis, internal low-density areas were observed in 8/10 cases (80.0%). Although these two CT features were rarely observed in distant metastases at diagnosis, they became apparent with progression of the metastatic tumor size. CONCLUSIONS: METex14 skipping-positive NSCLC tumors tend to invade surrounding tissue and possess internal low-density areas. These CT findings might be characteristic of METex14 skipping-positive NSCLC.

[A young case of pulmonary tuberculosis with atypical tumor shadow on chest computed tomography and its difficulty in diagnosis].

BACKGROUND: Diagnosis of pulmonary tuberculosis is usually made by diagnostic imaging such as chest X-ray or computed tomography (CT), and sputum test including smear and polymerase chain reaction (PCR) test. However there is difficulty in making diagnose when atypical imaging and negative sputum test are presented, followed by diagnostic delay. CASE: A 26-year-old man from Philippines consulted other clinic because of dry cough and was pointed out mass shadow in right upper lung field in his chest CT. He visited our office because of positive interferon gamma release assay, but repeated sputum test could not find tuberculosis. Bleeding from mass lesion failed to perform biopsy by bronchoscope, and we failed to find tuberculosis by smear and PCR test from bronchial brushing and wash. Transthoracic needle biopsy from his mass lesion revealed multiple non-caseous granuloma, and lead to make a decision about starting medication. Four weeks later sputum culture from his first visit revealed positive, and diagnosis of tuberculosis was made. DISCUSSION: For avoiding therapy delay it is important to perform invasive diagnostic procedure including histological examination and clinical decision of starting medication, when conservative diagnostic procedure such as sputum test or diagnostic imaging present atypical finding for diagnosing tuberculosis.

[Central diabetes insipidus caused by pituitary metastasis of lung cancer].

A 71-year-old man was admitted with high fever, thirst, polyposia and polyuria. After examination, lung cancer (adenocarcinoma T1NOM1, Stage IV) and central diabitus insipidus caused by pituitary metastasis of lung cancer, were diagnosed. We gave him desmopressin acetate, gamma knife surgery for pituitary metastasis and chemotherapy with paclitaxel and carboplatin, and his symptoms improved. However, his lung cancer progressed. Diabitus insipidus caused by lung cancer is rare.

Chemokine-mediated thymopoiesis is regulated by a mammalian Polycomb group gene, mel-18.

Multiple chemokines are made in the thymus, and they are likely to function in the fine control of cellular migration and regulation of thymic T cell development. Mice lacking the gene mel-18, a member of the mammalian Polycomb group genes, displayed impaired thymic T cell development. Here we report that expression of chemokine receptors CXCR4 and CCR9 are regulated by mel-18 and that CXCL12/SDF-1- and CCL25/TECK-mediated chemotactic activities are also affected by the loss of mel-18. In mel-18-/- mice, high expression of CXCR4 on CD4-CD8- cells might lead to trapping in the SDF-1 rich subcapsular region, while low expression of CCR9 on CD4+CD8+ cells might reduce cell migration to the medulla. Therefore, this member of the Polycomb group genes plays a role in thymic T cell migration and differentiation via the chemokine system.