Results from surgical treatment for thymoma. 43 years of experience

Post-Operative Outcomes Associated With Open Versus Robotic Thymectomy: A Propensity Matched Analysis

To compare post-operative outcomes associated with thymectomy performed using either open or robotic approaches. Retrospective cohort study from a single-center prospective registry consisting of patients undergoing thymectomy between 2000 and 2020. Patients were grouped according to surgical approach (open vs robotic). A propensity-score matching analysis was performed in a 2:1 open to robotic ratio, and surgical outcomes were evaluated. We analyzed 234 thymectomies (155 open; 79 robotic). Myasthenia gravis was present in 23.2% and 32.9% (P = 0.249) in the open and in the robotic group, respectively. All covariates were balanced in the matched groups (open n = 114; robotic n =5 9), except lesion size. The robotic approach was significantly associated with shorter surgical time (median 95 vs 65 minutes, P < 0.001), lesser clinical (21.1% vs 6.8%, P = 0.016) and surgical (11.4% vs 1.7%, P = 0.036) complications during the same hospitalization, less Clavien-Dindo grade 2 or higher complication rates (28.1 vs 15.3%, P = 0.048), chest tube duration (median: 3 vs 0 days, P < 0.001) and in-hospital length of stay (median: 5 vs 0 days, P < 0.001). Bleeding (P = 0.214), ICU length of stay (P = 0.167), reoperation rate (open, 1.8% vs robotic 0%), 90-day mortality (P = 0.341) and readmission rate post discharge (P = 0.277) were similar between the groups. In the matched population with primary thymic epithelial tumors, the completeness of resection rate was similar (open, 92.1% vs robotic 96.8%, P = 0.66.). Robotic thymectomy is associated with improved post-operative outcomes when compared to open thymectomy, without compromising the goals of oncologic surgery. Longer follow-up is needed to ensure oncologic equivalence.

Pathological tumor long-to-short axis ratio as a prognostic factor in patients with thymic epithelial tumors

Background

Thymic epithelial tumors (TETs) exhibit irregular shapes reflective of the heterogeneity in tumor growth and invasive properties. We aimed to identify the prognostic value of the pathological tumor long‐to‐short axis (L/S) ratio in TETs.

Methods

A retrospective study was performed on patients with TETs who underwent extended thymectomy between January 1999 and December 2019 in our institute. Patients were divided into two groups according to the threshold of the L/S ratio. Overall survival (OS) and progression‐free survival (PFS) were evaluated by Kaplan‐Meier analysis. The independent prognostic factors of TETs were identified by multivariate analysis. The performance of prediction models for the above survival outcomes with and without the L/S ratio was evaluated using an integrated time‐dependent area under the curve (iAUC).

Results

Eligible patients were divided into two groups based on higher (n = 42) and lower (n = 94) L/S ratios according to a threshold value of 1.39. A significant difference was found between the two groups only in disease progression (p = 0.001). Poorer survival outcomes were found from Kaplan‐Meier curves in the higher L/S ratio group (p < 0.05). In the multivariable analysis, the L/S ratio showed significant effects on OS and PFS (p < 0.05). The performance of models with the L/S ratio was better than that without the L/S ratio in predicting survival outcomes.

Conclusions

The pathological tumor L/S ratio is an independent prognostic factor for OS and PFS in patients with TETs, and an L/S ratio >1.39 is associated with worse survival outcomes.

How to obtain adequate biopsy specımen in suspected thymic tumors

Pathologic diagnosis of thymic tumors (TTs) can be made by surgical or nonsurgical procedures. About 20% of TTs had been diagnosed by pretreatment biopsy methods while the rest had gone to surgery for diagnosis and treatment. However, in the last two decades there was an increase in pretreatment procedures for optimal management of locally advanced or metastatic TTs. Pretreatment tissue diagnosis of a noninvasive TT is not a standard option but is required if there is suspect or atypical clinical presentation and imaging, an invasive tumor requiring a nonsurgical approach or preoperative chemotherapy or chemo-radiotherapy, strong possibility of lymphoma or unclear differential diagnosis between lymphoma or other solid tumor by imaging studies, or suspicion of a metastatic lesion. In surgical diagnosis anterior mediastinotomy, video-assisted thoracic surgery or mediastinoscopy can be chosen for invasive TTs whereas total resection is performed for small, noninvasive tumors. Nonsurgical diagnosis can be made by transthoracic fine or core needle biopsies (TTFNA, TTCNB), conventional bronchoscopy, endobronchial ultrasonography-guided transbronchial needle aspiration (EBUS-TBNA), endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) or medical thoracoscopy depending on procedural amenability according to tumor extension. TTFNA and TTCNB have been the most frequently used nonsurgical methods. However, there is an upward trend in using conventional bronchoscopy, EBUS-TBNA, EUS-FNA and medical thoracoscopy recently. To increase the diagnostic performance of these procedures in TTs, recommendations are (I) obtaining histologic specimens, (II) combining smears or liquid based cytology preparations and cell blocks, (III) obtaining multiple sufficient samples, (IV) combining histologic and cytologic specimens, (V) performing morphologic, immunohistochemical and molecular analyses on all specimens, (VI) using rapid onsite evaluation for cytologic specimens, (VII) correlating pathologic, clinical and radiologic findings, (VIII) consulting experienced pathologists.

Intermediate oncologic outcomes after uniportal video-assisted thoracoscopic thymectomy for early-stage thymoma

Background

Recent years have seen a trend towards utilizing a video-assisted thoracic surgery (VATS) approach for treatment of thymoma. Although increasing in practice, intermediate- and long-term oncologic outcome data is lacking for the VATS approach. There is no oncologic data for the uniportal VATS approach. We sought to evaluate the feasibility and impact on patient survival of uniportal VATS thymectomy for early-stage thymoma.

Method

The clinical outcomes for 17 patients with Masaoka stage I to II thymomas treated between January of 2009 and July of 2014 at a single institution were collected retrospectively. Primary endpoint was overall survival (OS) and secondary endpoint was recurrence-free survival (RFS).

Results

Ten women and seven men underwent uniportal VATS thymectomy; eleven had stage I thymoma and six had stage II thymoma. There were no conversions to open surgery. Operative mortality was zero. Mean tumor size was 3.8±1.0 centimeters, with a range of 1.9 to 6.0 centimeters. All patients underwent a R0 resection. Five-year survival was 100%, and the estimated RFS was 100%.

Conclusions

Our findings suggest that uniportal VATS thymectomy for early-stage thymoma is feasible, and the intermediate-term oncologic outcomes are comparable to historic standards for open and multi-incision VATS thymectomy. However, additional follow-up is required to evaluate for long-term oncologic outcomes.

Tumor location may affect the clinicopathological features and prognosis of thymomas

BACKGROUND

The current staging systems do not consider the tumor location of thymomas, and its clinical relevance is poorly understood. This study aimed to evaluate the impact of tumor location on the clinicopathological features and prognosis of thymomas.

METHODS

We performed a retrospective review of patients at our institution who underwent an extended thymectomy for a thymoma from 1976 to 2015. The tumor location was classified as either the superior or inferior mediastinum based on the maximum tumor diameter. The clinicopathological characteristics of the thymoma were also evaluated. Kaplan-Meier estimates and Cox proportional hazards models were used to analyze the survival outcomes and risk factors for recurrence.

RESULTS

A total of 194 patients with thymoma were eligible for this study. Compared with the inferior mediastinum group (n = 167), the superior mediastinum group (n = 27) had a higher frequency of myasthenia gravis (MG), advanced Masaoka-Koga staging, disease progression and recurrence (P < 0.05). The Kaplan-Meier analysis demonstrated thymomas in the superior mediastinum had worse survival outcomes that included overall survival, progression-free survival and disease-free survival (P < 0.05). The multivariate analysis showed tumor location was an independent prognostic factor for all the survival outcomes (P < 0.05). Furthermore, the tumor location (P = 0.004) and Masaoka-Koga stage (P < 0.001) were the only two independent risk factors for recurrence in the multivariate analysis.

CONCLUSIONS

The clinicopathological features of thymomas on MG, Masaoka-Koga staging, disease progression, and recurrence were different between locations of superior and inferior mediastinum locations. Thymomas in the superior mediastinum tended to be associated with worse survival and increased recurrence.

Spontaneous rupture of thymoma

We report a case of patient who presented to the hospital due to shoulder pain and was later diagnosed with ruptured thymoma. Shortly after being admitted to the hospital for the work up patient developed respiratory distress and underwent emergent endotracheal intubation. CT scan of the chest showed anterior mediastinal mass with associated right sided hemothorax. He subsequently underwent medial sternotomy with resection of the mass which turned out to be thymoma.

Prognostic significance of the preoperative neutrophil-to-lymphocyte ratio for complete resection of thymoma

PURPOSE

The preoperative peripheral neutrophil-to-lymphocyte ratio (NLR) is associated with a poor prognosis for various cancers. We evaluated the prognostic role of the preoperative NLR in patients with thymoma.

METHODS

We reviewed the medical records of 254 patients who underwent resection of thymic epithelial tumors at our institution. Patients were excluded if they had received steroid therapy, neoadjuvant therapy, or incomplete resection, or if they had thymic carcinoma or Good's syndrome, recurrence of thymoma, or missing data. The NLR was measured preoperatively, and outcomes of patients with a low (< 1.96) vs those with a high (≥ 1.96) NLR were compared statistically.

RESULTS

Of 159 eligible patients, 59 (37.1%) had a high NLR and 100 (62.9%) had a low NLR. Overall survival (OS), recurrence-free survival (RFS), disease-specific survival (DSS), disease-related survival (DRS), and the cumulative incidence of recurrence (CIR) differed significantly between the groups. Multivariate analyses revealed that a high NLR was independently associated with disease-related survival and a cumulative incidence of recurrence. A high NLR was also associated with a higher risk of recurrence of Masaoka stage I or II thymoma.

CONCLUSIONS

An elevated preoperative NLR was associated with poor outcomes after thymoma resection. Thus, the NLR may be a useful biomarker of the postoperative prognosis of thymoma.

Could thymomectomy be a reasonable option for non-myasthenic thymoma patients?

Background

Complete resection is the mainstay of treatment for thymoma, but few studies have investigated the extent of resection on normal thymus. Extended thymectomy is considered the treatment of choice for myasthenic patients with thymoma, while the optimal therapy for non-myasthenic patients is still a matter of debate. The aim of this retrospective study was to compare extended thymectomy vs. thymomectomy in non-myasthenic thymoma patients for (I) oncological outcome, (II) multicentric thymoma occurrence and (III) postoperative myasthenia gravis (MG) development.

Methods

A retrospective comparative study was conducted on 92 non-myasthenic patients with completely resected thymoma, according to the extent of resection: extended thymectomy (70 patients) vs. R0-mediastinal thymomectomy (22 patients). Clinical and pathological characteristics, oncological outcome and postoperative MG occurrence were compared between the two study groups.

Results

We did not observe any significant differences in gender, age, symptomology, preoperative chemotherapy, histology, tumour size, adjuvant therapy or complications. There were no recorded postoperative mortalities. Stage distribution was different between the two groups: similar percentages of early stage thymoma for both groups were present, but there was a prevalence of stage III for extended thymectomy and stage IV for thymomectomy (P<0.01). At a median follow-up of 77.4 months (range 1-255 months), no statistically significant differences were recorded in local recurrence (P=0.396), thymoma related deaths (P=0.504), multicentric thymoma occurrence (P=0.742) and postoperative MG development (P=0.343). A high preoperative anti-acetylcholine receptor antibodies (ARAb) serum titer assay was statistically correlated with postoperative MG occurrence (r=0.49, P<0.05).

Conclusions

Thymomectomy appears to be a valid treatment option for non-myasthenic thymoma patients, as this procedure was associated to the same 5-year oncological results, compared to extended thymectomy, for both stage I-II small thymomas and patients with giant unilateral masses, as well as advanced diseases. Moreover, thymomectomy was not associated to an increased rate of postoperative MG.

The Effect of Immunonutrition on the Postoperative Complications in Thymoma with Myasthenia Gravis

Object. To test whether preoperative immunonutrition is efficacious in reducing postoperative complications in patients of thymoma with myasthenia gravis (MG). Material and Methods. A total of 244 patients operated on for thymoma with myasthenia gravis were prospectively assigned to two groups, each receiving seven-day preoperative and seven-day postoperative nutrition. The patients in immunonutrition group were given oral immunonutrition (IN). The patients in control group received oral standard nutrition. Immunonutritional and inflammatory biomarkers (IgA, IgG, IgM, CD3t, CD4t, CD8t, CD4t/CD8t ratio, NK-cell, prealbumin, albumin, white blood cells counts, and C-reactive protein) and clinical variables (age, gender, BMI, performance status, type of thymoma, type of MG, operative time, pathology, operative approach, postoperative complications, quantity of drainage, hospital stays) were examined. Results. A significant reduction in the length of hospital stay, quantity of drainage, and postoperative complications was observed in the IN group (p < 0.05). An increase in the level of IgA, IgG, IgM, CD3+T, CD4+T, CD4+T/CD8+T, WBC, CRP, and NK-cell in the IN group was observed after thymectomy, while a decrease was seen with regard to prealbumin and albumin (p < 0.05). Conclusion. Preoperative immunonutrition support is effective in reducing postoperative complications in patients of thymoma with MG. It helps to lower the risk of postoperative infectious complications and hospital stays.

Preoperative misdiagnosis analysis and accurate distinguish intrathymic cyst from small thymoma on computed tomography

BACKGROUND

To evaluate the role of computed tomography (CT) in preoperative diagnosis of intrathymic cyst and small thymoma, and determine the best CT threshold for distinguish intrathymic cyst from small thymoma.

METHODS

We retrospectively reviewed the medical records of 30 patients (17 intrathymic cyst and 13 small thymoma) who had undergone mediastinal masses resection (with diameter less than 3 cm) under thoracoscope between January 2014 and July 2015 at our hospital. Clinical and CT features were compared and receiver-operating characteristics curve (ROC) analysis was performed.

RESULTS

The CT value of small thymoma [39.5 HU (IQR, 33.7-42.2 HU)] was significantly higher than intrathymic cyst [25.8 HU (IQR, 22.3-29.3 HU), P=0.004]. When CT value was 31.2 HU, it could act as a threshold for identification of small thymoma and intrathymic cyst (the sensitivity and specificity was 92.3% and 82.4%, respectively). The ΔCT value of enhanced CT value with the non-enhanced CT value was significantly different between small thymoma [18.7 HU (IQR, 10.9-19.0 HU)] and intrathymic cyst [4.3 HU (IQR, 3.0-11.7 HU), P=0.04]. The density was more homogenous in intrathymic cyst than small thymoma, and the contour of the intrathymic cyst was more smoothly than small thymoma.

CONCLUSIONS

Preoperative CT scans could help clinicians to identify intrathymic cyst and small thymoma, and we recommend 31.2 HU as the best thresholds. Contrast-enhanced CT scans is useful for further identification of the two diseases.

[Perioperative Outcomes and Long-term Survival in Clinically Early-stage Thymic Malignancies: Video-assisted Thoracoscopic Thymectomy versus Open Approaches]

背景与目的

胸腔镜胸腺切除术相比开放手术治疗早期（Masaoka-Koga Ⅰ期或Ⅱ期）胸腺恶性肿瘤在理论上具有优势，然而尚未有研究报道其在长期生存率方面的差异。本研究基于中国胸腺肿瘤研究协作组（Chinese Alliance for Research in Thymomas, ChART）的数据库对此进行了研究。

方法

以数据库中1994年到2012年间的1, 117例早期（Masaoka-Koga Ⅰ期或Ⅱ期）胸腺恶性肿瘤患者为研究对象。其中241例行胸腔镜胸腺切除术，876例行开放手术。采用单因素分析比较两组的临床资料与围手术期结果方面的差异。采用多因素分析明确影响长期预后的相关因素。

结果

与开放手术组相比，胸腔镜组的全胸腺切除比例更高（80.5% vs 73.9%, P=0.028），根治性切除率更高（98.8% vs 88.7%, P < 0.000），而复发率更低（2.9% vs 16.0%, P < 0.001），5年无瘤生存率更高（92% vs 83%, P=0.011），而两组的5年生存率接近（92% vs 92%, P=0.15）。Cox比例风险模型分析显示WHO分型、Masaoka-Koga分期和术后辅助治疗是影响胸腺恶性肿瘤长期生存的独立因素。

结论

胸腔镜胸腺切除术是治疗早期胸腺恶性肿瘤安全有效的方法，与开放手术相比其围手术期效果更好，肿瘤学疗效一致。

Reduced Port Thoracoscopic Surgery for Mediastinal and Pleural Disease: Experiences in a Single Institution

The purpose of this study was to present our current experience with reduced port thoracoscopic surgery (RPTS) for the treatment of mediastinal and pleural disease and thereafter discuss its indications and technical challenges. A total of 11 patients underwent surgery by the RPTS approach for the following conditions: thymoma (n = 2), bronchogenic cyst (n = 2), metastatic pleural tumor, thymic cyst, solitary fibrous tumor, pulmonary sequestration, pericardial cyst, neurinoma, and malignant lymphoma (n = 1). An Endo Relief forceps (Hope Denshi Co, Ltd, Chiba, Japan) was used for three of the surgical procedures. The elements of the data set consisted of gender, age, duration of operation, drain placement, hospital stay, mass location, and mass size. The median surgical time was 45 min (range, 40-78 min). There were no intraoperative complications and no need for a second surgery to open additional ports. The duration until chest tube removal was 1 day for all the cases. The median hospital stay was 4 days (range, 3-6 days). The median mass size was 2.2 cm (range, 1.2-4.2 cm). The median length of skin incision was 2.0 cm (range, 2.0-3.5 cm). In conclusion, RPTS for mediastinal and pleural disease may be a possible alternative approach to conventional multiportal video-assisted thoracoscopic surgery (VATS). Although it is technically plausible and feasible for selected cases, the issues of patient acceptability and cosmetic and oncological results remain to be determined in the future with randomized-controlled trials and long-term follow-up.

Perioperative outcomes and long-term survival in clinically early-stage thymic malignancies: video-assisted thoracoscopic thymectomy versus open approaches

BACKGROUND

Video-assisted thoracoscopic surgery (VATS) theoretically offers advantages over open thymectomy for clinically early-stage (Masaoka-Koga stage I and II) thymic malignancies. However, long-term outcomes have not been well studied. We compared the postoperative outcomes and survival from a cohort study based on the database of the Chinese Alliance for Research in Thymomas (ChART).

METHODS

Between 1994 and 2012, data of 1,117 patients having surgery for clinically early-stage (Masaoka-Koga stage I and II) tumors were enrolled for the study. Among them, 241 cases underwent VATS thymectomy (VATS group), while 876 cases underwent open thymectomy (Open group). Univariate analyses were used to compare the clinical character and perioperative outcomes between the two groups. And multivariate analysis was performed to determine the independent predictive factors for long-term survival.

RESULTS

Compared with the Open group, the VATS group had higher percentage of total thymectomy (80.5% vs. 73.9%, P=0.028), resection rate (98.8% vs. 88.7%, P=0.000) and less recurrence (2.9% vs. 16.0%, P=0.000). Five-year overall survival was 92% after VATS and 92% after open thymectomy, with no significant difference between the two groups (P=0.15). However, 5-year disease free survival were 92% in VATS group and 83% in Open group (P=0.011). Cox proportional hazards model revealed that WHO classification, Masaoka-Koga stage and adjuvant therapy were independent predictive factors for overall survival, while surgical approach had no significant impact on long-term outcome.

CONCLUSIONS

This study suggests that VATS thymectomy is an effective approach for clinically early-stage thymic malignancies. And it may offer better perioperative outcomes, as well as equal oncological survival.

Thymoma and thymic carcinomas

Thymomas (Ts) and thymic carcinomas (TCs) are rare tumours of the mediastinum with an incidence rate of 1.7/million per year in Europe. Histological classification is based on rate of non-malignant-appearing thymic epithelial cells and proportions of lymphocytes (A, AB, B1, B2, B3, and C), while staging system concerns localisation of the involved areas. Surgery is the mainstay of treatment with a 10-year survival of 80%, 78%, 75%, and 42% for stages I, II, III and IV, respectively, with an R0 resection. Radiotherapy has a role in selected cases (stage III patients or R1-2 residual) and platinum-based chemotherapy remains the standard of care for patients with advanced disease. A multimodality approach would be advisable when surgery is not recommended. Since molecular aberrations are poorly understood and few responses are reported, targeted therapies are yet being studied. In this review, we describe key aspects of clinical management for Ts and TCs.

Myasthenia gravis and thymic neoplasms: A brief review

Thymoma is the most common mediastinal tumor. They have varied presentation ranging from asymptomatic incidental mediastinal masses to locally extensive tumor with compressive symptoms and distant metastases. They have frequent association with various paraneoplastic syndromes (PNS). The most common PNS associated with thymoma is myasthenia gravis (MG). Patients of thymoma with MG have a favourable outcome due to early disclosure of the disease. Histologically they are classified into five subtypes and Masaoka-Koga staging system is used for staging. Surgery, chemotherapy and radiotherapy play an important role along with anti-myasthenia drugs. This review would like to highlight the association of thymoma with MG and associated clinical and therapeutic issues.

Recurrence after thymoma resection according to the extent of the resection

Background

Complete resection of the thymus is considered appropriate for a thymoma resection because any remaining thymic tissue can lead to local recurrence. However, there are few studies concerning the extent of thymus resection. Therefore, we conducted a retrospective study to investigate whether recurrence following thymoma resection correlated to the extent of resection.

Methods

Between 1986 and 2011, a total of 491 patients underwent resection of thymic epithelial tumors with curative intent. Of those, we excluded patients with an undetermined World Health Organization (WHO) histologic type, patients with type C thymoma, and patients who underwent incomplete resection (n = 21). The remaining 342 patients were reviewed retrospectively and compared recurrence according to the extent of resection.

Results

Extended thymectomy was performed in 239 patients (69.9%) and limited thymectomy was performed 103 patients (30.1%). In the extended thymectomy group, 29 recurrences occurred, and in the limited thymectomy group, 10 recurrences occurred.

Comparing rates of freedom from recurrence between two groups, there was no significant statistical difference in total recurrence (p =0.472) or local recurrence (p =0.798). After matching patients by stage and tumor size, there was no significant difference in freedom from recurrence between the two groups (p = 0.162). Additionally, after adjusting for histologic type and MG, there was also no significant difference (p = 0.125) between groups.

Conclusions

No difference in the rate of recurrence was observed in patients following limited thymectomy compared with extended thymectomy.

Thymic neoplasm: a rare disease with a complex clinical presentation

Thymic neoplasms constitute a broad category of rare lesions with a wide spectrum of pathologic characteristics and clinical presentations which therefore require a high index of suspicion to diagnose. The natural history of the disease is seldom predictable, anywhere from an indolent to an aggressively malignant course. Although the classification and staging of these lesions are complex and controversial, complete radical surgical resection remains the gold standard of therapy. Radiation and chemotherapy are important elements of the multimodality approach to treating these patients and it is important for thoracic surgeons to work closely with their colleagues in other disciplines in the management of and future research endeavors in thymic neoplasm. In this review, we discuss the evaluation of the patient with an anterior mediastinal mass, the classification and staging of thymic neoplasms, the role of surgery, radiation and chemotherapy in treating this disease, as well as future directions in research for novel targeted therapies.

The management of thymoma: a systematic review and practice guideline

INTRODUCTION

Thymoma is a rare tumor for which there is little randomized evidence to guide treatment. Because of the lack of high-quality evidence, a formal consensus-based approach was used to develop recommendations on treatment.

METHODS

A systematic refview of the literature was performed. Recommendations were formed from available evidence and developed through a two-round modified Delphi consensus approach.

RESULTS

The treatment recommendations are summarized as follows: Stage I--complete resection of the entire thymus without neoadjuvant or adjuvant therapy. Stage II--complete resection of the entire thymus with consideration of adjuvant radiation for high-risk tumors. Stage IIIA--surgery either initially or after neoadjuvant therapy, or surgery followed by adjuvant therapy. Stage IIIB--treatment may include a combination of chemotherapy, radiation, and/or surgery, or if technically possible, surgery in combination with chemoradiotherapy (concurrent cisplatin based). For bulky tumors, consideration should be given to sequential chemotherapy followed by radiation. Stage IVA--as per stage III, with surgery only if metastases can be resected. Stage IVB--treatment on an individual case basis (no generic recommendations). Recurrent disease--consider surgery, radiation, and/or chemoradiation. Chemoradiation should be considered in all medically inoperable and technically inoperable patients.

CONCLUSION

Consensus was achieved on these recommendations, which serve to provide practical guidance to the physician treating this rare disease.

Thymoma: update for the new millennium

Thymomas are relatively common tumors of the anterior superior mediastinum. They are usually relatively slowly growing tumors and their prognosis depends on the macroscopic and microscopic invasion of surrounding tissues. Surgery is the mainstay treatment of thymomas, and complete resection represents one of the most important prognostic factors in this disease. Other important prognostic indicators include the tumor stage and size and the presence of symptoms. Postoperative radiotherapy is indicated in tumors with invasion of surrounding tissues, even if resection was radical, since it improves local control and survival. Cytotoxic chemotherapy has been employed in several relatively small phase II studies and in advanced disease has been demonstrated to produce a 50%-80% objective response rate. Neoadjuvant cytotoxic chemotherapy and/or external beam radiotherapy has been used with some success in patients with tumors which are not readily resectable. Novel antiproliferative systemic agents, with both cytotoxic and cytostatic mechanisms of action, are being tested in ongoing prospective clinical trials.

Multiple thymoma with myotonic dystrophy

A case of multiple thymoma associated with myotonic dystrophy is reported. The patient was a 42-year-old man who had two separate encapsulated thymoma in the anterior mediastinum, at 3 cm in diameter on the right side, and at 4 cm in diameter on the left. Extended thymo-thymomectomy was performed. Microscopically, the tumor in the right thymic lobe was predominantly mixed type, and that in the left predominantly epithelial type. Neuromuscular disease appeared to develop, with severe sputum retention in the larynx and he was referred to neurology at 6 months after surgery. On examination, he presented a characteristic hatchet face, muscle atrophy, muscle weakness, percussion myotonia and grip myotonia, and diagnosis was revised to be multiple thymoma associated with myotonic dystrophy. This association is extremely rare. It is difficult to clarify whether this association was a syndrome or coincidence.