[Osteosarcoma Secondary to Polyostotoic Fibrous Dysplasia of the Ribs].

Sarcomatous transformation of fibrous dysplasia is extremely rare. We present the case of a 54-yearold man with multiple rib masses, multiple enlarged lymph nodes throughout the body, and multiple osteolytic lesions on computed tomography( CT). A positron emission tomography( PET) scan showed abnormal enhancement in each. A needle biopsy of the right supraclavicular fossa lymph node revealed sarcoidosis. Considering the possibility of malignancy associated with sarcoidosis, a rib tumor resection and mediastinal lymph node biopsy were performed to confirm the diagnosis of the rib lesion. The pathology results showed that the rib mass was a low-grade central osteosarcoma and the mediastinal lymph node was sarcoidosis. The distribution of the lesions was consistent with osteosarcoma secondary to multiple fibrous bone dysplasia. As the osteosarcoma was low grade, the patient was followed up. Three years after surgery, there was no increase in residual disease.

[Thymoma with Pure Red-cell Aplasia and Hypogammaglobulinemia].

Thymoma presenting concurrent pure red-cell aplasia (PRCA) and hypogammaglobulinemia are extremely rare. A 67-year-old woman with a short of breath was referred to our hospital due to anemia and the chest abnormal shadow. Laboratory investigations revealed a hemoglobin level of 5.6 g/dl and reticulocyte percentage of 0.2%. Her serum gamma-globulin level was low. Chest computed tomography (CT) revealed a 7-cm tumor in the left upper mediastinum. We diagnosed the patient with thymoma accompanied by PRCA and hypogammaglobulinemia. The patient underwent thymectomy and PRCA has been successfully treated by postoperative cyclosporine administration. Monthly intravenous infusion of gamma-globulin has been necessary for the control of hypogammaglobulinemia. Currently, she is doing well without recurrence of thymoma or PRCA five years after the surgery.

[Mucoepidermoid Carcinoma Suspectedly Developed from a Bronchogenic Cyst in the Posterior Mediastinum].

Mucoepidermoid carcinoma developing from a bronchogenic cyst is extremely rare. We present a case of a 74-year-old man with a cystic mass in the posterior mediastinum detected by chest computed tomography( CT) and magnetic resonance imaging. A bronchogenic cyst or neurogenic tumor was suspected. He did not accept surgical treatment and was followed up at outpatient. Since the enlargement of the mass was shown by chest CT after seven years, the resection of the mass was performed by thoracoscopic surgery, however the cyst wall remained due to the severe adhesion and the residual mucosa was cauterized. The mass was diagnosed as a mucoepidermoid carcinoma by pathology which was likely to develop from a bronchogenic cyst. After postoperative radiotherapy, the patient is well without recurrence 10 months after surgery.

[Effectiveness of Pembrolizumab for Pulmonary Pleomorphic Carcinoma with Pleural Dissemination and Gingival Metastasis].

We present a case of a 67-year-old woman who was pointed out a 1.8 cm nodule in the left inferior lobe by chest computed tomography( CT). Lung cancer was suspected and the surgery was scheduled. Before surgery, perioperative oral care was performed and gingival tumor doubtful of metastatic lesion was found. After the resection of the lung tumors, the diagnosis of pleomorphic carcinoma with pleural dissemination and gingival metastasis was established. Because high programmed cell death 1 ligand 1 (PD-L1) expression was demonstrated in the specimen of the lung, she was treated with pembrolizumab as an initial treatment, which led to a complete response. Twenty months after initiating of pembrolizumab therapy, she is doing well without recurrence of pleomorphic carcinoma.

[Mesothelioma of Unknown Primary Site with Resection of Mediastinal Lymph Node Metastasis].

A 63-year-old male underwent biopsy of a mediastinal lymph node. Intra-operative frozen section diagnosis was metastatic mesothelioma. The primary site of mesothelioma was not detected in the thoracic cavity. One year later, he was again removed a mediastinal lymph node metastasis, but the primary site was not detected. Eight months later, he was performed right neck and mediastinal lymph node dissection due to additionally appeared lymph node metastases, but the primary site was not detected. He is well 6 months after last surgery with postoperative adjuvant chemotherapy.

[Thymic carcinoma with vascular resection].

Thymic carcinomas are rare neplasm. The standard treatment for advanced thymic carcinoma has not yet been established, and the prognosis is poor. We report 3 cases of thymic carcinoma involving major vessely. Case 1:The aortic arch and the innominate vein were involved. Case 2:The left brachiocephalic vein was involved. Case 3:Tumor invaded to superior vena cava. Complete resection of the tumor was possible with vascular reconstruction.

[Congenital broncho-esophageal fistula in an elderly patient with lung abscess].

A 60-year-old man who had been treated for pneumonia by another hospital was suspected to have a broncho-esophageal fistula, and was referred to our hospital for surgical treatment. Chest computed tomography( CT) demonstrated a lung abscess. Upper gastrointestinal endoscopic examination demonstrated an esophageal diverticulum. He underwent the resection of the fistula and left lower lobectomy of lung under left thoracotomy. Operative findings showed no severe adhesion around fistula, suggesting its congenital origin, which was also pathologically supported later. He suffered from postoperative empyema by anaerobe infection, which was successfully controlled by open drainage.