Clinical outcomes of left upper segmentectomy vs. lobectomy for early non-small-cell lung cancer: a nationwide database study in Japan.

PURPOSE: Given that left upper lobe and right upper and middle lobes share a similar anatomy, segmentectomy, such as upper division and lingulectomy, should yield identical oncological clearance to left upper lobectomy. We compared the prognosis of segmentectomy with that of lobectomy for early stage non-small-cell lung cancer (NSCLC) in the left upper lobe. METHODS: We retrospectively examined 2115 patients who underwent segmentectomy or lobectomy for c-stage I (TNM 8th edition) NSCLC in the left upper lobe in 2010. We compared the oncological outcomes of segmentectomy (n = 483) and lobectomy (n = 483) using a propensity score matching analysis. RESULTS: The 5-year recurrence-free and overall survival rates in the segmentectomy and lobectomy groups were comparable, irrespective of c-stage IA or IB. Subset analyses according to radiological tumor findings showed that segmentectomy yielded oncological outcomes comparable to those of lobectomy for non-pure solid tumors. In cases where the solid tumor exceeded 20 mm, segmentectomy showed a recurrence-free survival inferior to that of lobectomy (p = 0.028), despite an equivalent overall survival (p = 0.38). CONCLUSION: Segmentectomy may be an acceptable alternative to lobectomy with regard to the overall survival of patients with c-stage I NSCLC in the left upper lobe.

Benefit of Adjuvant Chemotherapy for Patients Older Than 75 Years With Completely Resected p-Stage II-IIIA Non-Small-Cell Lung Cancer: A Retrospective Cohort Study Using Japanese Nationwide Real-World Data.

BACKGROUND: The efficacy of adjuvant chemotherapy (ACT) in elderly patients with completely resected p-stage II-IIIA non-small-cell lung cancer (NSCLC) remains unclear because all previous randomized controlled trials on ACT have been conducted among patients aged <75 years. Thus, this study aimed to evaluate the effectiveness of ACT in elderly patients with completely resected NSCLC. PATIENTS: We extracted the nationwide data of 812 patients aged ≥75 years who underwent lobectomy with mediastinal nodal dissection in 2010 and were diagnosed with p-stage II-IIIA NSCLC, from nationwide registry data accumulated in 2016. METHODS: We classified the 812 patients into 2 groups based on the ACT administration status and analyzed the differences in their postoperative overall survival (OS). RESULTS: Overall, 295 patients received ACT (36.3%; group A), whereas 517 patients did not (63.70%; group N). Group A showed significantly better OS as a whole (hazard ratio [HR]: 0.650 [95% confidence interval {CI}: 0.526-0.804]), in the p-stage II subset (HR: 0.688 [95% CI: 0.513-0.925]), and p-stage IIIA subset (HR: 0.547 [95% CI: 0.402-0.743]) than group N. Even after propensity score matching, group A showed significantly better OS as a whole (HR: 0.626 [95% CI: 0.495-0.792]), in the p-stage II subset (HR: 0.690 [95% CI: 0.493-0.964]), and p-stage IIIA subset (HR: 0.554 [95% CI: 0.398-0.772]) than group N. CONCLUSION: ACT is recommended even in elderly patients with completely resected p-stage II-IIIA NSCLC. Hence, physicians should not avoid ACT in patients with completely resected NSCLC based solely on age.

Nationwide prospective registry database of patients with newly diagnosed untreated pleural mesothelioma in Japan.

Due to the scarcity of large-sized prospective databases, the Japanese Joint Committee for Lung Cancer Registry conducted a nationwide prospective registry for newly diagnosed and untreated pleural mesothelioma. All new cases diagnosed pathologically as any subtype of pleural mesothelioma in Japan during the period between April 1, 2017, to March 31, 2019, were included before treatment. Data on survival were collected in April 2021. The eligible 346 patients (285 men [82.3%]; 61 women [17.7%]; median age, 71.0 years [range, 44-88]) were included for analysis. Among these patients, 138 (39.9%) underwent surgery, 164 (47.4%) underwent non-surgical therapy, and the remaining 44 (12.7%) underwent best supportive care. The median overall survival for all 346 patients was 19.0 months. Survival rates at 1, 2, and 3 years for all patients were, 62.8%, 42.3%, and 26.5%, respectively. Median overall survival was significantly different among patients undergoing surgery, non-surgical treatment, and best supportive care (32.2 months vs. 14.0 months vs. 3.8 months, p < 0.001). The median overall survival of patients undergoing pleurectomy/decortication and extrapleural pneumonectomy was 41.8 months and 25.0 months, respectively. Macroscopic complete resection resulted in longer overall survival than R2 resection and partial pleurectomy/exploratory thoracotomy (41.8 months vs. 32.2 months vs. 16.8 months, p < 0.001). Tumor shape, maximum tumor thickness, and sum of three level thickness were significant prognostic factors. The data in the prospective database would serve as a valuable reference for clinical practice and further studies for pleural mesothelioma.

Is adjuvant chemotherapy for completely resected p-stage IA (>2 cm) and stage IB non-small-cell lung cancer beneficial for elderly patients? A large, retrospective cohort study based on real-world data from Japan.

OBJECTIVE: The efficacy of tegafur-uracil as adjuvant chemotherapy for patients with completely resected stage I non-small-cell lung cancer is proven; however, its efficacy for elderly patients remains unclear. Herein, we evaluated the effectiveness of adjuvant chemotherapy for elderly patients with completely resected stage I non-small-cell lung cancer based on real-world Japanese data using propensity score matching. METHODS: This retrospective study extracted data from a nationwide registry study, performed in 2016, on patients ≥75 years who underwent lobectomy with mediastinal nodal dissection for non-small-cell lung cancer in 2010 and were diagnosed with p-stage IA (>2 cm) or stage IB non-small-cell lung cancer. We classified the 1294 patients into two groups-Group A, postoperative adjuvant chemotherapy (n = 295, 22.8%) and Group N, no adjuvant chemotherapy (n = 999, 77.2%)-and analyzed differences in postoperative overall survival between groups. RESULTS: Group A showed no advantage in overall survival over Group N as a whole (hazard ratio: 0.824 [95% confidence interval: 0.631-1.076]), in p-stage IA (hazard ratio: 0.617 [95% confidence interval: 0.330-1.156]) and in p-stage IB (hazard ratio: 0.806 [95% confidence interval: 0.597-1.088]) subsets. Even after propensity score matching, Group A showed no significant advantage in overall survival over Group N as a whole (hazard ratio: 0.975 [95% confidence interval: 0.688-1.381]), in p-stage IA (hazard ratio: 1.390 [95% confidence interval: 0.539-3.586]) and in p-stage IB (hazard ratio: 0.922 [95% confidence interval: 0.633-1.343]). CONCLUSIONS: adjuvant chemotherapy for completely resected p-stage IA (>2 cm) and stage IB non-small-cell lung cancer showed no benefit for recommendation for elderly patients; considering the risk of adverse events, we do not recommend adjuvant chemotherapy for elderly patients.

Features of anaplastic lymphoma kinase rearrangement in early-stage lung cancer: Analysis of a nationwide Japanese database.

BACKGROUND AND OBJECTIVES: Anaplastic lymphoma kinase (ALK) rearrangement is a representative driver mutation in lung cancer. However, the biology of early-stage ALK-rearranged lung cancer remains unclear. We aimed to assess the clinicopathological features, prognostic implications, and influence of ALK rearrangement on the postoperative course in surgically resected lung cancer. METHODS: We retrospectively analyzed data from the Japanese Joint Committee of Lung Cancer Registry database. Of the 12 730 patients with lung adenocarcinoma, 794 (6.2%) were tested for ALK rearrangement and were included. RESULTS: ALK rearrangements were detected in 76 patients (10%). The 5-year overall survival (OS) rate was significantly higher in the ALK rearrangement-positive group than in the ALK rearrangement-negative group (p = 0.030). Multivariable analysis revealed that ALK rearrangement was an independent prognostic factor for improved OS (hazard ratio, 0.521; 95% confidence interval, 0.298-0.911; p = 0.022). Regarding the postrecurrence state, there was no difference in the initial recurrence sites between both groups. Administration of ALK-tyrosine kinase inhibitors (TKIs) improved postrecurrence survival in any treatment lines. CONCLUSION: In one of the largest national surveys, ALK rearrangement was associated with improved long-term outcomes in surgically resected patients. ALK-TKIs may be an important treatment strategy for ALK rearrangement-positive lung adenocarcinoma in the postrecurrence state.

A retrospective multi-institutional survey of characteristics of surgically treated spontaneous hemopneumothorax patients.

OBJECTIVE: The Japan Society for Pneumothorax and Cystic Lung Disease conducted a nationwide retrospective survey to identify correlations between the timing of surgical intervention and the incidence of transfusion, and to examine the factors contributing to the need for transfusion among clinical features in surgically treated spontaneous hemopneumothorax (SHP) patients. METHODS: We analyzed the characteristics and perioperative results of patients with SHP who underwent thoracoscopy or thoracotomy between April 2009 and March 2019. RESULTS: From 17 institutions, 171 cases were enrolled in this study. Receiver-operating characteristic curve analyses for the incidence of transfusion and waiting time before the operation revealed an area under the curve of 0.54 (95% confidence interval [CI] 0.44-0.64). Therefore, we did not compare the clinical features using a cutoff value of waiting time before the operation. More than 80% of the patients underwent surgical treatment within 24 h from admission. Multivariate analysis revealed that the total volume of hemorrhage was the only significant factor contributing to the incidence of transfusion (p = 0.00011, odds ratio: 0.03, 95% CI 0.0051-0.18). Moreover, multivariate analyses revealed that the waiting time before the operation was a contributing factor for prolonged total hospitalization (p < 0.0001, estimated regression coefficient: 0.036, 95% CI 0.027-0.045). CONCLUSION: In SHP patients, a reduction in the waiting time before the operation significantly contributed to not the avoidance of transfusion but a reduction in total hospitalization time. In addition, transfusion was performed depending on the volume of blood loss.

Hazard Function Analysis of Recurrence in Patients with Curatively Resected Lung Cancer: Results from the Japanese Lung Cancer Registry in 2010.

To optimize postoperative surveillance of lung cancer patients, we investigated the hazard function of tumor recurrence in patients with completely resected lung cancer. We analyzed the records of 12,897 patients in the 2010 Japanese Joint Committee of Lung Cancer Registry who underwent lobectomy to completely resect pathological stage I-III lung cancer. The risk of postoperative recurrence was determined using a cause-specific hazard function. The hazard function for recurrence exhibited a peak at approximately 9 months after surgery, followed by a tapered plateau-like tail extending to 60 months. The peak risk for intrathoracic recurrence was approximately two-fold higher compared with that of extrathoracic recurrence. Subgroup analysis showed that patients with stage IIIA adenocarcinoma had a continuously higher risk of recurrence compared with patients with earlier-stage disease. However, the risk of recurrence in patients with squamous cell carcinoma was not significantly different compared with that more than 24 months after surgery, regardless of pathological stage. In conclusion, the characteristics of postoperative tumor recurrence hazard in a large cohort of lung cancer patients may be useful for determining the time after surgery at which patients are at the highest risk of tumor recurrence. This information may improve stage-related management of postoperative surveillance.

Evaluation of age-related thymic changes using computed tomography images: A retrospective observational study.

We aimed to investigate if Computed tomography (CT) attenuation values can help improve the identification of age-related changes in the thymus. We assessed CT images of 405 patients aged 0 to 80 years. We measured the area of the anterior mediastinum at the level of the carina and its average CT attenuation value. We evaluated the thymic area, the ratio of the thymus area to the total thoracic area, and the CT attenuation value. Additionally, we evaluated changes in the thymus area in the 0 to 13-year age group. The area of the thymus decreased from birth to the middle 20s. After the middle 20s, the area tended to increase and plateau till after 50 years of age. The ratio of the thymic area to the thoracic area decreased from age 0 to 20 years, but remained stable after 20 years of age. The CT attenuation values were stable from birth to puberty, decreased after puberty, and were stable again in the late 50s and beyond. The thymus of children showed mass formation, but the shape changed with age. No significant differences in the CT attenuation value were found across underlying conditions for the 0 to 13-year age group. The decrease in the CT attenuation values, observed with advancing age, reflects adipose degeneration of the thymus, indicating that by the late 50s, thymic tissue is replaced completely by adipose tissue. Our data suggest that adipose degeneration of the thymus begins after puberty and advances with age.

The prognostic impact of lung adenocarcinoma predominance classification relating to pathological factors in lobectomy, the Japanese Joint Committee of Lung Cancer Registry Database in 2010.

OBJECTIVE: We studied the prognosis and clinicopathological background of lung adenocarcinoma predominance among patients who underwent lobectomy using data from the Japanese Joint Committee of Lung Cancer Registry. METHODS: Two thousand eight hundred sixty-three cases were extracted. Recurrence free survival (RFS) rates, overall survival (OS) rates and clinicopathological factors and epidermal growth factor receptor (EGFR) mutation status were examined. RESULTS: Median follow-up period was 65.5 months. Adenocarcinoma predominance was sub-grouped according to OS and RFS rate. In pathological stage I, 5-year RFS and OS rates were respectively 92.2% and 95.8% in group A (adenocarcinoma-in-situ + minimally invasive adenocarcinoma), 89.3% and 92.1% in group B (lepidic), 79.2% and 89.7% in group C (papillary + acinar + variants) and 69.0% and 79.0% in group D (solid + micropapillary). In pathological stage II + IIIA, they were, 43.6% and 72.4% in B, 39.5% and 66.9% in C and 31.0% and 53.7% in D. Group D showed significant worst outcome both in stage I and II + IIIA. Up stage rate from clinical stage I to pathological stage II + IIIA was 0.0%, 3.7%, 15.9% and 33.3%. The frequency of lymph-vessel, vascular, pleura invasion and positive EGFR mutation were 0.0%, 0.0%, 0.0% and 57.1% in group A, 15.6%, 10.0%, 12.1% and 55.1% in B, 36.6%, 31.8%, 29.7% and 44.9% in C, 50.2%, 57.8%, 38.9% and 21.3% in D. In group D, lymph-vessel, vascular and pleura invasion were most, EGFR mutation was least frequent not only in pathological stage I but also stage II + IIIA. In multivariate analysis, age, pathological stage, vascular invasion, and group D were independent factors affected RFS and OS. CONCLUSION: Limited to lobectomy cases, solid + micropapillary was independent prognostic factor both in early and locally advanced stage. Its malignant degree was related to the frequency of pathological invasive factors and EGFR mutation status.

Limited resection for stage IA radiologically invasive lung cancer: a real-world nationwide database study.

OBJECTIVES: Radiologically invasive non-small-cell lung cancer, defined as consolidation size to maximum tumour diameter ratio of over 0.5, is associated with pathological invasiveness and worse prognosis. However, there are no real-world, nationwide database studies on limited resections that consider radiological invasiveness. This study aimed to investigate the prognostic validity of limited resection, such as segmentectomy and wedge resection, in cStage IA (TNM 8th edition) radiologically invasive lung cancer. METHODS: We conducted a retrospective analysis of patients who underwent complete resection according to the Japanese Joint Committee of Lung Cancer Registry Database. The relationship between surgical procedures and prognosis was examined using stratification by cT factor and radiological invasiveness. RESULTS: Among the 5,692 patients enrolled, lobectomy, segmentectomy and wedge resection were performed in 4,323 (80.0%), 657 (11.5%) and 712 (12.5%) patients, respectively. Multivariable analysis with or without propensity score matching indicated that older age, poor performance status and wedge resection were significantly associated with worse prognosis and that patients who underwent segmentectomy showed an equivalent prognosis to those who underwent lobectomy. Subset analyses revealed that segmentectomy showed an equivalent prognosis to lobectomy in patients with cT1b or less, but not in those with cT1c, especially for non-pure radiological invasive cT1c; 5-year overall survival rates were 91.4% vs 90.4% in cT1b with non-pure radiological invasiveness and 80.0% vs 83.8% in cT1b with pure radiological invasiveness, respectively. CONCLUSIONS: Segmentectomy can be an alternative to lobectomy in patients with radiologically invasive lung cancer with cT1b or less but not in those with cT1c.

A Case of Lymphangiomatosis With Infected Lymphangiomas Effectively Treated by Thoracoscopic Debridement and Drainage.

A 40-year-old woman with lymphangiomatosis also had an intrathoracic lymphangioma infection. Since the age of 8 years, the patient had undergone repeated abdominal and mediastinal cyst surgeries and had received a diagnosis of lymphangiomatosis. At this time, she showed a high fever of 38.5°C. Cultures of both blood and fluid aspirated from the cyst were positive for Staphylococcus aureus. Chest CT imaging revealed an enlarged right-sided mediastinal cystic lymphangioma with new septa in it. A chest tube was inserted into the cyst to remove effusion. The patient was then started with the antibacterial drug cefazolin at 3 g/d. But effective drainage was difficult because of the high viscosity of the effusion and septa working as barriers. We removed these components with endoscopic surgical instruments and via a pulsed-lavage system under general anesthesia. Postoperative CT images showed reexpanded lung structure and reduced cyst size. The patient has taken a favorable course for 2 years.

A case report of idiopathic pleuroparenchymal fibroelastosis with severe respiratory failure in pregnancy.

BACKGROUND: Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare lung disease that manifests as parenchymal fibrosis of the upper lung lobe and pleura. There have been no reports of IPPFE complicating pregnancy. Here, we report a case of IPPFE that deteriorated rapidly during pregnancy. CASE PRESENTATION: A 29-year-old woman presented with dyspnea and dry cough at 19 weeks of gestation. IPPFE with acute exacerbation was suspected on chest computed tomography (CT). Despite steroid treatment, her condition progressed. A cesarean section was performed at 28 weeks of gestation. On postoperative day 26, she underwent living-donor lung transplantation. She was discharged a year after transplantation. CONCLUSION: Our experience suggested that when pregnancy is complicated by PPFE, the disease may deteriorate rapidly. In this case, even though IPPFE with acute exacerbation was diagnosed during pregnancy, live birth was achieved, and the mother survived after lung transplantation. Lung transplantation should be considered in these patients because, once advanced, pulmonary lesions may be irreversible.

Thymidine phosphorylase affects clinical outcome following surgery and mRNA expression levels of four key enzymes for 5-fluorouracil metabolism in patients with stage I and II non-small cell lung cancer.

The expression levels of thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), thymidylate synthase (TS) and orotate phosphoribosyltransferase (OPRT) may predict the clinical efficacy of 5-fluorouracil-based chemotherapy in patients with cancer. We herein investigated the differences in the mRNA levels of these enzymes in non-small-cell lung cancer (NSCLC) and evaluated their prognostic value for NSCLC treated by surgical resection. The intratumoral mRNA levels of TP, DPD, TS, and OPRT were quantified in 66 patients with pathological stage I and II NSCLC (adenocarcinoma or squamous cell carcinoma) following complete resection according to the Danenberg Tumor Profile method. The TP level was the only significant prognostic factor for disease-specific survival (DSS) following complete resection; the mean TP mRNA level differed significantly between the high and low mRNA expression groups. The DSS at 5 years was significantly higher in the low TP mRNA compared with that in the high TP mRNA expression group (83.4 vs. 58.6%, respectively; P=0.005). A Cox proportional hazards model revealed that pathological stage, sex, and TP expression were independent prognostic factors for DSS in patients with stage I and II NSCLC following complete resection. Thus, TP level may be used to monitor treatment efficacy and predict the outcome of NSCLC patients.

[Lung Cancer Associated with Hamartoma;Report of a Case].

A 65-year-old male was admitted to our hospital for evaluation of an abnormal shadow in the left lung field of chest roentgenogram. A chest computed tomography scan revealed an ill-defined nodule in the superior lingular segment of left lung and a calcified nodule in the left pulmonary apex region. A diagnosis of lung adenocarcinoma in the left lingular was made by transbronchial cytology and the left upper lobectomy with lymph node dissection was performed. Pathological diagnosis was primary lung adenocarcinoma in the superior lingular segment of left lung (pT1aN0M0, stage I A) and hamartoma in the left pulmonary apex region. It was considered to be important to discriminate a hamartoma from a metastasic lesion in order to conduct correct treatment.

Adherence and feasibility of 2 treatment schedules of S-1 as adjuvant chemotherapy for patients with completely resected advanced lung cancer: a multicenter randomized controlled trial.

BACKGROUND: We conducted a multicenter randomized study of adjuvant S-1 administration schedules for surgically treated pathological stage IB-IIIA non-small cell lung cancer patients. METHODS: Patients receiving curative surgical resection were centrally randomized to arm A (4 weeks of oral S-1 and a 2-week rest over 12 months) or arm B (2 weeks of S-1 and a 1-week rest over 12 months). The primary endpoints were completion of the scheduled adjuvant chemotherapy over 12 months, and the secondary endpoints were relative total administration dose, toxicity, and 3-year disease-free survival. RESULTS: From April 2005 to January 2012, 80 patients were enrolled, of whom 78 patients were eligible and assessable. The planned S-1 administration over 12 months was accomplished to 28 patients in 38 arm A patients (73.7%) and to 18 patients in 40 arm B patients (45.0%, p = 0.01). The average relative dose intensity was 77.2% for arm A and 58.4% for arm B (p = 0.01). Drug-related grade 3 adverse events were recorded for 11% of arm A and 5% of arm B (p = 0.43). Grade 1-3 elevation of bilirubin, alkaline phosphatase, aspartate aminotransferase, and alanine transaminase were more frequently recorded in arm A than in arm B. The 3-year disease-free survival rate was 79.0% for arm A and 79.3% for arm B (p = 0.94). CONCLUSIONS: The superiority of feasibility of the shorter schedule was not recognized in the present study. The conventional schedule showed higher completion rates over 12 months (p = 0.01) and relative dose intensity of S-1 (p = 0.01). Toxicity showed no significant difference among the shorter schedule and the conventional schedule, except for grade 1-3 elevation of bilirubin. TRIAL REGISTRATION: This randomized multicenter study was retrospectively registered with the UMIN-CTR (UMIN000016086, registration date December 30, 2014).

[Descending Necrotizing Mediastinitis Survived by Two Operations;Report of a Case].

The patient, a 65-year-old woman, visited at her local doctor's office with the chief complaint of pharyngeal pain. After being administered antibacterial drugs, hyperthermia persisted and the pharyngeal pain became exacerbated. She was referred to our hospital and diagnosed as a retropharyngeal abscess and descending necrotizing mediastinitis (DNM). She was urgently hospitalized and surgery was performed. The mediastinal pleura was incised with thoracoscopic guidance and curettage, irrigation, and drainage were performed. Additional drainage was determined to be necessary based on findings from subsequent chest computed tomography and a prolonged inflammatory reaction. Therefore, on hospital day 7, 2nd surgery were performed, and tracheotomy was additionally performed with curettage of the neck abscess. The patient was taken off mechanical ventilation on hospital day 18, and discharged on hospital day 55.

The Usefulness of Positron-Emission Tomography Findings in the Management of Anterior Mediastinal Tumors.

PURPOSE: We performed a retrospective analysis to evaluate the usefulness of positron-emission tomography/computed tomography (PET/CT) findings in the classification and management of anterior mediastinal tumors. METHODS: Between 2006 and 2015, 105 patients with anterior mediastinal tumor received PET/CT. 18F-fluorodeoxyglucose (18F-FDG)-PET images were obtained 60 minutes after the injection of 18F-FDG. RESULTS: The histological classifications were as follows: thymoma (n = 49), thymic carcinoma (TC) (n = 19), malignant lymphoma (ML) (n = 8), teratoma (n = 7), thymic cyst (n = 14), and others (n = 8). Upon visual inspection (SUV max: >2.0), all of the malignant tumors showed 18F-FDG accumulation (with the exception of one type A thymoma). Two of the 14 thymic cysts and three of the seven teratomas showed slight 18F-FDG accumulation. The SUV max values of the low-grade thymomas, high-grade thymomas, TCs and MLs were 3.14 ± 0.73, 4.34 ± 1.49, 8.59 ± 3.05, and 10.08 ± 2.53, respectively, with significant differences between the low- and high-grade thymomas, and between TCs and MLs. The sensitivity, specificity and accuracy of 18F-FDG in the detection of low-grade thymomas and thymomas with a maximum diameter of ≤50 mm and an SUV max of ≤3.4 were 85%, 48%, and 60%, respectively. CONCLUSION: FDG-PET/CT is an objective and useful modality in the differential diagnosis and management of anterior mediastinal tumors.

Video-assisted thoracic surgery for primary myelolipoma of the posterior mediastinum.

BACKGROUND: Myelolipoma is an uncommon tumor comprising adipose tissue and normal hematopoietic cells and mainly occurs in the adrenal cortex. Mediastinal myelolipoma is very rare; we report a case of posterior mediastinal myelolipoma that required surgical resection. CASE PRESENTATION: A 56-year-old male was diagnosed with a posterior mediastinal tumor by computed tomography. The tumor was originally noted in 2005, and during follow-up in March 2014, it was found to have increased in size. During consultation at our hospital, on magnetic resonance imaging (MRI), we considered the possibility that the tumor was malignant. Consequently, we resected the tumor by video-assisted thoracic surgery (VATS). The histopathological findings revealed that the tumor had undergone intrathoracic extramedullary hematopoiesis. However, after considering the patient's background and histopathological findings, we diagnosed the tumor as a thoracic extra-adrenal myelolipoma. CONCLUSIONS: Pathological analysis was instrumental in clarifying the diagnosis. We recommend surgery as a treatment option for posterior mediastinal tumors.