Kazunori Iwatani

Size of Metastatic and Nonmetastatic Mediastinal Lymph Nodes in Non-small Cell Lung Cancer

Objective: To determine the optimum selection of mediastinal lymph nodes for biopsy in non-small cell lung cancer (NSCLC), lymph nodes with or without metastasis at each mediastinal station were ranked in size in patients with pathological N2 disease. Methods: Twenty-five NSCLC patients with pathological N2 disease who underwent pulmonary resection with complete mediastinal lymph node clearance were examined. Of 114 mediastinal lymph node stations dissected, 47 had metastases and 67 did not. The sizes of 259 nodes in the 47 positive lymph node stations were measured. Of these 259 nodes, 137 had metastases and 122 did not. The short- and long-axis diameters of the 259 lymph nodes were ranked in each lymph node station. Results: Mean short- and long-axis diameters of lymph nodes with metastases were significantly greater than those without (p < 0.001). In 47 metastatic lymph node stations, the short- and long-axis diameters were greatest in a metastatic node in 44 (94%) and 42 (89%) respectively, whereas in the remaining 3 (6%) and 5 (11%), the second largest but not the largest node was positive. None of the largest lymph nodes with metastasis were smaller than the second largest lymph node at each station. Four of the 10 patients with adenocarcinoma (40%) had metastasis in the second largest but not in the largest node measured by long-axis diameter, a significant difference from one in eight (12.5%) among the squamous cell carcinoma cases (p = 0.04). Conclusion: For mediastinal lymph node biopsy, both the largest and the second largest node at each station should be sampled, especially in adenocarcinoma. If only the largest lymph node is selected, false-negative results will occur at a rate of about 10%.

Microscopic-Sized “Microthymoma” in Patients With Myasthenia Gravis

BACKGROUND In 2005, Cheuk et al reported two patients with microscopic-sized thymomas and proposed the term microthymoma to distinguish it from the nodular hyperplasia of thymic epithelium, so-called microscopic thymoma. Here, we present microthymomas that were found in 196 patients with myasthenia gravis (MG) who had undergone thymectomy. MATERIALS AND METHODS Thymic tissues in 196 patients with MG who underwent thymectomy or thymothymomectomy were examined. Of these patients, 73 patients had thymoma indicated by CT before surgery, and the other 123 patients had no mediastinal tumors. From the resected thymic tissues, an average of 14 hematoxylin-eosin-stained sections (range, 4 to 55 sections) were prepared for microscopic examination. The histologic type of the thymoma was classified according to the World Health Organization (WHO) classification. RESULTS From the 196 patients, we found three microthymomas in 3 patients (1.5%). While these three tumors could not be seen grossly in pathology section, they were found microscopically (range, 2 to 4 mm). The histologic subtype according to the WHO classification system was B1 in one patient and B2 in two patients. CONCLUSION Microthymoma was found in 3 of 196 patients (1.5%) with MG. Microthymoma might exist in thymus of patients with MG, even in patients who have no thymoma indicated by CT.

Cyclin D1 blocks the anti-proliferative function of RUNX3 by interfering with RUNX3-p300 interaction.

Transcriptional function of cyclin D1, whose deregulation is frequently observed in human cancers, has been suggested to contribute to cancer formation. In the present study, we show that cyclin D1 protein inhibits RUNX3 activity by directly binding to it and interfering with its interaction with p300 interaction in lung cancer cells. Cyclin D1 inhibits p300-dependent RUNX3 acetylation and negatively regulates cyclin-dependent kinase (cdk) inhibitor p21 expression. These transcriptional effects of cyclin D1 do not require cdk4/6 kinase activation. We propose that cyclin D1 provides a transcriptional switch that allows the tumor suppressor activity of RUNX3 to be repressed in cancer cells. Since RUNX3 plays tumor suppressive roles in a wide range of cancers, a non-canonical cyclin D1 function may be critical for neoplastic transformation of the epithelial cells in which RUNX3 regulates proliferation.

Extrapleural pneumonectomy via a lower door open thoracotomy with reconstruction of the diaphragm and pericardium using autologous materials for mesothelioma

We performed extrapleural pneumonectomy (EPP) with combined resection of the diaphragm and pericardium via a lower door open (LDO) thoracotomy to treat right malignant pleural mesothelioma (MPM) in a 57-year-old man. Specifically, we extended the standard posterolateral thoracotomy skin incision along the anterior costal arch, and performed the thoracotomy by cutting into the 6th to 9th costal cartilage. The resulting defect of the diaphragm and pericardium were reconstructed with a reversed latissimus dorsi (LD) muscle flap and a fascia lata graft, respectively. The patient had an uneventful postoperative course without dyspnea or dysfunction of the extremities. The LDO thoracotomy provided a good operative field, especially for the costo- and cardiophrenic angles, allowing a complete resection of the diaphragm to be performed easily. Furthermore, the reversed LD muscle flap and fascia lata graft proved to be ideal autologous materials for reconstruction of both the diaphragm and the pericardium.

Thoracoscopic phrenic nerve patch insulation to avoid phrenic nerve stimulation with cardiac resynchronization therapy

A 76‐year‐old female was implanted with a cardiac resynchronization therapy (CRT) device, with the left ventricular lead implanted through a transvenous approach. One day after implantation, diaphragmatic stimulation was observed when the patient was in the seated position, which could not be resolved by device reprogramming. We performed thoracoscopic phrenic nerve insulation using a Gore‐Tex patch. The left phrenic nerve was carefully detached from the pericardial adipose tissue, and a Gore‐Tex patch was inserted between the phrenic nerve and pericardium using a thoracoscopic technique. This approach represents a potential option for the management of uncontrollable phrenic nerve stimulation during CRT.