Thymoma Exhibiting Spontaneous Regression With Cystic Change Due to Acute Infarction: A Case Report and Literature Review.

Spontaneous regression (SR) of thymoma is rare. We report a case of a surgically resected thymoma due to cystic changes owing to acute ischemic infarction with an increased anti-acetylcholine receptor antibody level. A 61-year-old male underwent a computed tomography (CT) scan, which showed a 4.9 cm anterior mediastinal tumor and slight right pleural effusion. Blood test results indicated an elevated white blood cell count of 13300/mL. One month later, an enhanced CT scan at our hospital showed spontaneous mediastinal tumor regression to 3.7 cm and no pleural effusion. The tumor contained homogeneous low-density areas on enhanced CT, which showed high intensity on T2-weighted magnetic resonance imaging, indicating cystic changes. He had no symptoms of myasthenia; however, his anti-acetylcholine receptor antibody level was slightly elevated (0.4 nmol/L). Suspecting a thymoma, an extended total thymectomy through a median sternotomy was performed. Histopathological analysis confirmed the diagnosis of thymoma type B2 and Masaoka stage I. SR is due to acute intratumoral infarction. At two years postoperatively, no tumor recurrence or development of myasthenia gravis was observed. Thymomas should be included in the differential diagnosis of anterior mediastinal tumors that regress spontaneously with cystic changes, pleural effusion, and an elevated inflammatory response. Mature cystic teratoma rupture should be differentiated, but preoperative biopsy is often challenging owing to necrotic and fibrous tissues; therefore, early surgical resection is required for diagnosis and treatment.

[Surgically Resected Cases of Mediastinal Ganglioneuroma Detected in Adults].

A ganglioneuroma is a rare, benign, neurogenic tumor originating from the sympathetic ganglion. Mediastinal ganglioneuroma are mostly detected in children, typically around 10 years of age, and are rarely identified in adults. Herein, we report two surgically resected cases of mediastinal ganglioneuroma in adults. In Case 1, a 53-year-old man, without any symptom, underwent a computed tomography, revealing a 3.2 cm well-defined paravertebral superior mediastinal tumor with long craniocaudal axis. In case 2, a 29-year-old woman presented with newly-developed ptosis and a history of left-sided facial hypohidrosis since the age of 10. Chest computed tomography (CT) revealed a 7.8 cm well-defined paravertebral superior mediastinal tumor with long craniocaudal axis. Both patients were initially suspected to have neurogenic tumors, particularly schwannomas. They underwent mediastinal tumor resections, requiring sympathetic nerve trunk dissection. Pathological examination confirmed the diagnosis of ganglioneuromas in both cases. Mediastinal ganglioneuroma must be differentiated from schwannoma, the most common neurogenic tumor in adults. Unlike schwannoma, ganglioneuroma cannot be enucleated, therefore attention should be focused on complications associated with sympathetic nerve trunk dissection, such as Horner's syndrome, hyperhidrosis, and arrhythmia. Identifying this rare entity and its characteristic imaging aids in preoperative differentiation, strategizing surgical approaches, and predicting complications.

Intralobar pulmonary sequestration presenting as multiple nodular pulmonary lesions and focal emphysema.

The features of intralobar pulmonary sequestration vary on computed tomography (CT). Many cases demonstrate a mass or cystic lesion within a lower lobe. We report herein a case of a 55-year-old, female patient presenting with right back pain. Contrast enhanced (CE) CT revealed multiple, nodular, pulmonary lesions suggesting recurrent infections with surrounding focal emphysema. Three-dimensional (3D) reconstruction demonstrated a sequestrated lung segment with a systemic, arterial blood supply. Based on these findings, intralobar pulmonary sequestration was diagnosed. Intralobar pulmonary sequestration can present as multiple, nodular, pulmonary lesions with focal emphysema rather than as a mass or cyst. CE-CT with 3D reconstruction is useful for diagnosing this condition. Patients with recurrent pulmonary infections have a high index of suspicion of intralobar pulmonary sequestration.

Atypical type A thymoma component identified by pulmonary metastasectomy 11 years after surgery of type AB thymoma.

Atypical type A thymomas exhibit more aggressive features than conventional type A thymomas. Type AB thymomas rarely have atypical type A components. We report a rare case of type AB thymoma with an atypical type A component, that was identified after pulmonary metastasectomy 11 years after the primary surgery and long-term follow-up after recurrence. A 61-year-old female underwent extended thymectomy for an anterior mediastinal tumor 11 years prior and was diagnosed with type AB thymoma (Masaoka stage II). Five years ago, follow-up computed tomography showed well-circumscribed pulmonary nodules up to 1.0 cm in both lungs. All the pulmonary nodules grew slowly; however, one of the nodules grew to 1.6 cm, and thoracoscopic wedge resection was performed for diagnosis. Pathologically, the pulmonary nodule was consisted of type A thymoma component. Conventional type AB thymomas are usually locally aggressive neoplasms; thus, we reviewed the tissue slides of primary thymomas. Histologically, cytological atypia, hypercellularity, and increased mitosis are observed in the type A component. Consequently, the diagnosis was revised to a type AB thymoma with an atypical type A component. The pulmonary nodule exhibited the same atypical type A features. Pulmonary metastasectomy was performed two more times as volume-reduction surgery. The residual metastasis was located only in the lung with slow growth, 4 years after the first pulmonary resection; therefore, we followed up as an outpatient without treatment.

Multifocal Cholesterol Granulomas of the Thymus: A Case Report of Positron Emission Tomography- Positive Benign Tumor of the Anterior Mediastinum.

Cholesterol granulomas of the thymus are extremely rare benign entities. Herein, we describe a case of cholesterol granuloma in a 45-year-old man who presented with multifocal anterior mediastinal lesions on computed tomography (CT). Positron emission tomography (PET)-CT revealed increased fluorodeoxyglucose uptake, with a maximum standardized uptake value of 8.3. Diffusion-weighted magnetic resonance imaging (MRI) revealed extreme hypointensity. He underwent total thymectomy by median sternotomy for presumed multiple thymoma. On histopathological analysis, cholesterol granuloma of the thymus was confirmed, and the patient had an uneventful postoperative course without recurrence for 28 months. Cholesterol granuloma of the thymus is a PET-CT-positive benign tumor with unique histological findings. The MRI findings were indicative of hypocellularity associated with a benign entity, whereas the PET-CT findings corresponded to granulomatous inflammation. Therefore, concurrent use of PET-CT and MRI can be helpful in distinguishing between benign cholesterol granulomas and malignant anterior mediastinal tumors.

Pulmonary metastasis of matrix-producing carcinoma mimicking small cell lung cancer.

Matrix-producing carcinoma (MPC) of the breast is an extremely rare subtype of invasive breast cancer. MPC is characterized by the production of a cartilaginous or osseous matrix without spindle cells. It is an aggressive carcinoma, often presenting as triple-negative breast cancer. MPC frequently metastasizes to the lungs; however, it rarely reoccurs as a solitary pulmonary metastasis. We report a case of a 77-year-old non-smoking woman with a solitary pulmonary metastasis of MPC, which mimicked small cell lung cancer (SCLC). Initially, the pulmonary metastasis was misdiagnosed as SCLC based on its morphological and immunochemical features, including focal positivity for CD56 and thyroid transcription factor-1. Although the portion of the chondromyxoid matrix of the primary site was not small, that of the metastatic site was small. A focal cartilaginous matrix deposition of pulmonary metastasis from MPC could make it difficult to differentiate from SCLC. We should acknowledge that the portion of chondromyxoid matrix may differ between primary and distant metastatic sites in MPC.

Successful Video-Assisted Thoracoscopic Removal of a Chest Tube Protruding Deep Into the Pulmonary Hilum.

Tube thoracostomy is an invasive procedure frequently used to drain pleural fluid collections or to manage pneumothorax, wherein the lungs commonly sustain trauma. In some cases, deep pulmonary hilar injuries are managed by anatomical lung resections. A deep hilar injury with the chest tube protruding into the lung parenchyma is a rare complication of tube thoracostomy. We report the case of a patient with tube thoracostomy-related deep pulmonary laceration treated using video-assisted thoracic surgery (VATS). A 74-year-old man with a left-sided pneumonia-associated empyema underwent tube thoracostomy for drainage of intrathoracic purulent collection at another hospital; however, chest radiography and computed tomography (CT) revealed intrusion of the 22 Fr chest tube into the left lower lobe parenchyma for approximately 10 cm toward the pulmonary hilum, with the chest tube tip located near the left main bronchus and pulmonary artery. Although no massive intrapulmonary hemorrhage, pneumothorax, or pneumomediastinum was observed, multiple pyothoracic cavities were present. He was transferred to our hospital the following day in a hemodynamically stable condition. The next day, he underwent both surgical chest tube removal and decortication for empyema. Owing to the worsening of his physical condition and due to prolonged severe inflammation and lack of appetite, without any sign of bleeding or chest tube air leak, a two-port VATS with sparing of the lung parenchyma was attempted. After decortication, the penetrating chest tube was slowly removed. No hemorrhage or air leaks were observed at the site of penetration, requiring no sutures or dressing. Following his uneventful postoperative course, he was discharged on day 9. In selected cases, anatomic lung resection can be avoided, even for deep hilar injuries, depending upon the degree of intrapulmonary hemorrhage and the presence of air leak from the chest tube, and the CT scan findings.

Thymoma exhibiting spontaneous regression with developing myasthenia gravis: A case report.

Spontaneous regression (SR) of thymoma is rare. A 44-year-old man with right chest pain underwent computed tomography (CT), which showed an 11.0 cm mass in the anterior mediastinum and right pleural effusion. He refused surgery and was sent home without medication and additional treatment. One year later, the mass had regressed to 5.5 cm, and the right pleural effusion had disappeared. He was then lost to follow-up. Four years after the initial visit, he presented with diplopia and fatigue. A significant increase in his anti-acetylcholine receptor antibody levels led to myasthenia gravis (MG) diagnosis. CT revealed a regressed mediastinal mass (3.0 cm). After extended thymectomy, histologic analysis confirmed a thymoma type B2, Masaoka stage IIa. The SR was due to intratumoral infarction. This report is the first to describe MG developing during SR. Anterior mediastinal tumors undergoing SR should be differentiated from thymomas and MG perioperative development should be considered.

Utility of Ultrasonography in Assessing Periaortitis Associated with Retroperitoneal Fibrosis: A Case Report.

Periaortitis is a rare vascular manifestation and is often associated with retroperitoneal fibrosis. Herein, we describe a case of periaortitis accompanied by retroperitoneal fibrosis in a patient who developed acute kidney insufficiency due to bilateral ureteral stenosis. Ultrasonography at presentation detected thickness of the outer layer of the bilateral common iliac artery and right internal and external iliac arteries, consistent with periaortitis. Moreover, follow-up ultrasound images revealed subsiding of the thickness of the arterial wall in response to treatment with corticosteroids. Because of its noninvasiveness and handiness, ultrasonography has become popular for the assessment of large vessels in clinical practice, particularly monitoring for affected lesions. Computed tomography, magnetic resonance imaging, and positron emission tomography are currently used for the diagnosis and monitoring of periaortitis, but in this case, ultrasonography was utilized in the diagnosis and monitoring of periaortitis as a supportive imaging modality, as the use of contrast agents was contraindicated because of renal insufficiency.

Cryobiopsy as a reliable technique for the preoperative identification of micropapillary/solid components in early-stage lung adenocarcinoma.

OBJECTIVES: Micropapillary (MIP) and solid (SOL) subtypes of early-stage lung adenocarcinomas are associated with lymph node metastasis and local recurrence after limited resection. Preoperative identification of these components may influence the decisions of treatment strategy, additional lymph node evaluation, indication for limited resection, and extent of lymph node dissection. However, conventional biopsy specimens are insufficient for identifying these subtypes, especially MIP components. Cryobiopsy can collect larger tissue samples with fewer crush artifacts than conventional forceps biopsy, which would be helpful for detecting MIP/SOL components. Thus, this study aimed to analyze the feasibility of using cryobiopsy for MIP/SOL subtype detection. MATERIAL AND METHODS: Consecutive patients who underwent surgery for clinical IA lung cancer following a preoperative diagnosis of adenocarcinoma by cryobiopsy at our institution between October 2017 and July 2019 were retrospectively examined. The concordance rate of MIP/SOL subtypes between the specimens obtained by cryobiopsy and surgery was investigated. RESULTS: In total, 115 patients were evaluated. There were 26 (22.6%) and 14 (12.2%) patients with MIP and SOL subtypes, respectively. For concordance of MIP/SOL subtypes, the sensitivity was 65.7% (95% confidence interval [CI]: 57.7-65.7%). For the primary or secondary predominant patterns, a more satisfactory concordance rate of 72.2% (95% CI: 52.6-86.2%) was obtained. On assessing each subtype, high sensitivity was noted in SOL-predominant patterns (85.7%, 95% CI: 56.5%-96.0%) and MIP-secondary predominant patterns (83.3%, 95% CI: 45.8-97.0%). However, SOL-secondary predominant patterns revealed low sensitivity (0%, 95% CI, 0-38.2%). Overall, the MIP subtypes had higher sensitivity than the SOL subtypes (65.4% vs. 50.0%). CONCLUSION: Cryobiopsy could be reliable for identifying MIP/SOL components, especially the MIP component, in clinical stage IA adenocarcinomas.

Infratentorial onset of progressive multifocal leukoencephalopathy in a patient with systematic lupus erythematosus complicated with lymphoma: a case report.

Progressive multifocal leukoencephalopathy (PML) is a rare opportunistic infection of the central nervous system caused by reactivation of JC virus (JCV). Typical PML shows confluent, bilateral but asymmetric, subcortical lesions in the supratentorial white matter on magnetic resonance imaging (MRI). We report here a 50-year-old woman with systemic lupus erythematosus complicated with lymphoma who developed PML with atypical brain MRI findings limited to the infratentorial area at presentation. She presented with numbness on the right side of the face, including her tongue, clumsiness of the right hand, and gait disturbance, after completion of remission induction therapy for lymphoma, including rituximab. Brain MRI demonstrated a solitary lesion limited to the cerebellum and brainstem, but a definitive diagnosis could not be made from cerebrospinal fluid study or tentative histologic evaluation of brain biopsy specimens. Despite methylprednisolone pulse therapy, her neurological deficits progressively worsened. One month later, in-depth analysis of her cerebrospinal fluid and brain biopsy specimens confirmed the presence of JCV. Eventually, the localised unilateral crescent-shaped cerebellar lesions on MRI expanded to the contralateral cerebellum, middle cerebellar hemisphere, pons, and midbrain and finally developed multifocal invasion into the white matter of the cerebral hemispheres. Our case suggests that PML could first present with a solitary infratentorial lesion in immunocompromised patients.

Chest wall muscle atrophy as a contributory factor for forced vital capacity decline in systemic sclerosis-associated interstitial lung disease.

OBJECTIVE: To investigate the potential contribution of accessory respiratory muscle atrophy to the decline of forced vital capacity (FVC) in patients with SSc-associated interstitial lung disease (ILD). METHODS: This single-centre, retrospective study enrolled 36 patients with SSc-ILD who underwent serial pulmonary function tests and chest high-resolution CT (HRCT) simultaneously at an interval of 1-3 years. The total extent of ILD and chest wall muscle area at the level of the ninth thoracic vertebra on CT images were evaluated by two independent evaluators blinded to the patient information. Changes in the FVC, ILD extent, and chest wall muscle area between the two measurements were assessed in terms of their correlations. Multiple regression analysis was conducted to identify the independent contributors to FVC decline. RESULTS: Interval changes in FVC and total ILD extent were variable among patients, whereas chest wall muscle area decreased significantly with time (P=0.0008). The FVC change was negatively correlated with the change in ILD extent (r=-0.48, P=0.003) and was positively correlated with the change in the chest wall muscle area (r = 0.53, P=0.001). Multivariate analysis revealed that changes in total ILD extent and chest wall muscle area were independent contributors to FVC decline. CONCLUSION: In patients with SSc-ILD, FVC decline is attributable not only to the progression of ILD but also to the atrophy of accessory respiratory muscles. Our findings call attention to the interpretation of FVC changes in patients with SSc-ILD.

Segmental Hypoganglionosis of the Colon: A Case Report.

A 64-year-old woman was admitted to hospital with persistent abdominal pain. She had been hospitalized with similar symptoms on five occasions during a period of 2 years. Computed tomography revealed dilatation and fecal impaction from the ileum to the transverse colon. A barium enema and simultaneous ileus tube radiography showed a narrow segment of descending-sigmoid colon. Colonoscopy showed no mucosal change. Her symptoms did not improve with conservative therapy, so descending and sigmoid colectomy was performed. Histologic examination showed disappearance of ganglion cells; axon of Meissner's plexuses was present, and the number of Auerbach's plexuses was decreased. The definitive diagnosis was segmental hypoganglionosis (SH) of the colon. The postoperative course was uneventful, and the functional result was positive at 1 year postoperatively. SH is extremely rare; however, surgical intervention is expected to be of benefit. Therefore, it is important to keep SH in mind when treating patients with chronic obstruction of the left side of the colon.

Usefulness of a Colonic Stent for Colonic Obstruction Caused by Lung Cancer Metastasis.

The gastrointestinal tract is not a common site for metastasis from lung cancer, and colonic metastases are especially rare. Although surgical intervention can improve colonic obstruction, perioperative mortality is high in patients with advanced malignancy, and these patients experience a significant deterioration in quality of life postoperatively. This report describes an uncommon case of colonic metastasis from non-small cell lung cancer (NSCLC), in which colonic obstruction was improved with a self-expanding metallic stent. A 62-year-old man was admitted to our hospital for progressively worsening abdominal pain. He had been treated with immunotherapy and chemotherapy after being diagnosed with NSCLC (T4N2M1) 1.5 years earlier. Enhanced computed tomography showed intestinal obstruction and a mass in the colon at the hepatic flexure. Histopathological analysis of a biopsy specimen confirmed NSCLC metastasis. Considering his general condition, endoscopic stenting was chosen as an urgent decompression procedure. He was discharged 45 days after stenting and was able to resume immunotherapy. Emergency stenting could be offered at experienced centers when operative intervention is not part of the treatment plan, as it is safe and improves the efficiency of care along with the quality of life.