Thymoma: update for the new millennium

Thymoma: An Overview

Thymomas are considered one of the most prevalent types of mediastinal epithelial tumors, which frequently develop in the anterior mediastinum. Due to their rarity, these tumors' nomenclature, classification, and staging are likely to be the subject of debate and argument for most expert pathologists. Furthermore, the significance of thymoma histologic classifications have been debated over the past twenty years. While certain advocates argue that staging at the time of diagnosis is more significant, others believe that histologic subtyping has a significant impact on how patients behave clinically. In this review, we will focus on some of the challenges that diagnostic surgical pathologists may experience while evaluating the histopathology of thymomas and staging these tumors. We will additionally glance over the clinical characteristics of these distinct tumors and the current management strategy.

Oral Lichen Planus in a Patient With a Thymoma: A Rare Finding

We present a rare case of ulcerative oral lichen planus that was associated with a thymoma discovered during the management phase, seven months after the initial diagnosis of oral lichen planus. Thymectomy was performed and investigations revealed pure red cell aplasia. Although rare, the association of a thymoma should be considered in recording the medical history of patients presenting with oral lichen planus.

Granulocyte Colony Stimulating Factor-induced Immune Recovery Uveitis Associated with Cytomegalovirus Retinitis in the Setting of Good Syndrome

Purpose: To report a case of immune recovery uveitis (IRU) secondary to cytomegalovirus (CMV) retinitis in a patient with Good syndrome treated with granulocyte colony stimulating factor (GCSF).Methods: A case report.Case: A 54-year-old woman with a history of Good syndrome for 2 years presented with chronic panuveitis in her right eye for 6 months. She had received multiple doses of GCSF for a pulmonary infection. Her visual acuity was hand movement in the right eye. Few anterior chamber cells, dense vitreous haze, and chorioretinal lesions were noted. Granular retinal atrophic lesions without obvious infiltration were observed during diagnostic vitrectomy. Polymerase chain reaction of the vitreous sample was positive for CMV DNA. A diagnosis of IRU secondary to CMV retinitis was made. The inflammation was controlled with topical steroids after surgery.Summary: In this report, we present a patient with Good syndrome who developed IRU secondary to CMV retinitis.

Atypical presentation of Good syndrome: acute hepatitis from hepatitis B virus reactivation

Good syndrome (GS) is a primary immunodeficiency (PID) that presents in middle aged to older adults with features of thymoma, hypogammaglobulinemia, CD4 T lymphopenia, inverted CD4/CD8+ ratio, and impaired T-cell mitogen proliferative responses. We present a patient, a 62-year-old female, who first presented with disease manifestation of acute hepatitis from hepatitis B virus (HBV) reactivation, which was subsequently complicated by recurrent hospitalizations for recurrent pneumonia and concomitant Helicobacter pylori and cytomegalovirus enteritis. She was later found to have thymoma and hypogammaglobulinemia and was diagnosed with GS. Although the well-known importance of T cell is in directing B-cell responses in the immunopathology of thymoma, low levels of natural killer and CD4+ γδ T cells may also be the cause of both low immune surveillance of tumor development and weak clearance of viral infection. Hence, the temporal sequence of opportunistic infections following HBV reactivation and thymoma discovery may reflect a loss of immune surveillance as the first manifestation of PID.

A case of thymoma in myasthenia gravis: Successful outcome after thymectomy

INTRODUCTION

Thymic abnormalities occur as hyperplasia and thymoma. Myasthenia gravis is commonly present in thymoma. Thymectomy possesses risk due to anatomical proximity with vital thoracic structures and myasthenia crisis.

PRESENTATION OF CASE

Forty five years female with complaints of difficulty swallowing and weakness of upper limb muscles upon investigation showed mass in mediastinum and antibody test for myasthenia gravis positive. Medical management was done for a month followed by thymectomy. There were no intra and postoperative complications. Medical management was stopped one month after surgery and she is symptom free.

DISCUSSION

Thymectomy is the standard of care where median sternotomy is the mainstay approach to surgery. Various other surgical approaches and complications revolving around surgery has been discussed.

CONCLUSION

Surgical removal of thymoma cured myasthenia gravis in our case. We focused on proper preoperative optimization of myasthenia gravis symptoms before thymectomy.

Thymoma appearing 9 years after the resection of squamous cell carcinoma of the lip: A case report of triple primary tumors and literature review

The occurrence of second primary tumor (SPT)following malignancy treatment is common. In patients with head and neck (H&N) cancer, SPTs principally occur in the H&N region, lungs or esophagus. Therefore, patient follow-up after cancer treatment is important in order to detect recurrence, metastasis and new primary tumors. However, no standard guidelines on lifelong follow-up imaging are available. Herein, we report a patient who presented with three metachronous primary tumors-squamous cell carcinoma (SCC) of the tongue, SCC of the lip and type A thymoma. The third tumor was incidentally detected during follow-up using contrast-enhanced computed tomography (CT) 9 years following resection of the second tumor. To the best of our knowledge, this specific combination of metachronous tumors has not yet been reported. Based on the literature review, we observed that thymoma occurs following H&N cancer treatment. Therefore, to ensure that the presence of subsequent thymomas is not overlooked, we suggest regular lifelong follow-up using contrast-enhanced CT in patients who had previously been diagnosed with H&N cancer. The literature review revealed that thymomas occur in patients with H&N cancer and should be detected at the earliest convenience.

Good's Syndrome Patients Hospitalized for Infections: A Single-Center Retrospective Study

Good's syndrome (GS) is a rare combination of thymoma and hypogammaglobulinemia, resulting in immunodeficiency. Patients with GS are highly susceptible to bacterial infection, particularly encapsulated bacterial infection in upper and lower respiratory tracts. Good's syndrome patients with moderate-to- severe infection are often hospitalized. Clinical features of GS patients remain to be characterized.Patients with the discharge diagnosis of GS and simultaneous infection from Peking Union Medical College Hospital between January 2001 and July 2015 were retrospectively analyzed.Among 14 hospitalized GS patients, 12 of them were admitted for severe infections. Mean patient age was 56.7 + 10.1 years. Average concentrations of serum IgG, IgA, and IgM were 2.3 + 1.9 g/L, 0.28 + 0.28 g/L, and 0.06 + 0.07 g/L, respectively. Respiratory and intestinal tracts were the most common sites for infection, which occurred in 7 and 4 patients, respectively. Pathogens identified in 10 patients included cytomegalovirus in 5 patients, Pneumocystis jirovecii, Clostridium difficile in 2 patients, Klebsiella pneumonia in 2 patients, and Streptococcus pneumonia and Hemophilus influenza in 1 patient. Ten patients were treated with antibiotics and immunoglobulin replacement. Only 1 patient who was on immunosuppressant therapy died from P. jirovecii pneumonia.Infection was the most frequent cause for hospitalization of GS patients. Both respiratory and intestinal tracts were the most common sites of infection. Cytomegalovirus and P. jirovecii represented 2 common opportunistic pathogens isolated from hospitalized GS patients with infections.

Cytokine profiles contribute to understanding the pathogenic difference between Good syndrome and oral lichen planus: two case reports and literature review

We described and analyzed the pathogenic difference between Good syndrome (GS) and oral lichen planus (OLP) in oral mucosa. Good syndrome (GS) is a rare disease characterized by B and T cell immunodeficiency associated with hypogammaglobulinemia and thymoma. GS patients frequently develop oral lichenoid lesions with lymphocytic infiltration beneath the basal layer. Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa characterized by destruction of basal cells by Langerhans cells, macrophages, and T lymphocytes. Although the histological features of the lesions of both diseases are very similar, the pathogenesis of GS in the oral mucosa remains unknown. In this study, we thus investigated the expression of infiltrating lymphocyte subsets (CD3, CD20, CD4, and CD8) and T helper (Th) cytokines including interferon (IFN)-γ (Th1 type), interleukin (IL)-4 (Th2 type), IL-17 (Th17 type), and IL-10 (regulatory T cell type) by immunohistochemistry in buccal mucosa specimens from 2 GS patients compared with 15 OLP patients. All patients showed a predominance of CD3 T cells over CD20 B cells, and CD4 Th cells over CD8 cytotoxic T cells. This polarization was especially prominent in GS. IFN-γ and IL-10 were strongly detected in the infiltrating lymphocytes of all patients. However, IL-4 and IL-17 were detected in OLP patients only. These results suggest that the pathogenesis of GS is different from that of OLP. GS is a unique inflammatory disorder characterized by dysfunction of Th2 and Th17 immune reactions via abnormal T-B cell interaction.

Expression of RAGE and HMGB1 in thymic epithelial tumors, thymic hyperplasia and regular thymic morphology

Recently, a role of the receptor for advanced glycation endproducts (RAGE) in myasthenia gravis was described. RAGE and its ligand high mobility group box 1 (HMGB1) play key roles in autoimmunity and cancer. To test whether these molecules are involved in patients with thymic abnormalities we applied immunohistochemical analysis in 33 cases of thymic epithelial tumors, comprising 27 thymomas and 6 thymic carcinomas, and 21 nonneoplastic thymuses. Both molecules were detected in neoplastic epithelial cells: RAGE staining was most intense in WHO type B2 thymomas and thymic carcinomas (p<0.001). HMGB1 nuclear staining was strongest in A and AB, and gradually less in B1 = B2>B3>thymic carcinoma (p<0.001). Conversely, HMGB1 cytoplasmic staining intensities were as follows: A and AB (none), B1 (strong), B2 (moderate), B3 and thymic carcinoma (weak); (p<0.001). Fetal thymic tissue showed a distinct expression of RAGE and HMGB1 in subcapsular cortical epithelial cells which was found in 50% of myasthenic patients. Furthermore RAGE and HMGB1 were expressed in thymocytes, macrophages, Hassall's corpuscles, thymic medulla, and germinal center cells in myasthenic patients. Immunohistochemistry results were complemented by systemic measurements (immunosorbent assay): serum levels of soluble RAGE were significantly reduced in patients with epithelial tumors (p = 0.008); and in invasive tumors (p = 0.008). Whereas RAGE was equally reduced in thymic hyperplasia and epithelial tumors (p = 0.003), HMGB1 was only elevated in malignancies (p = 0.036). Results were most pronounced in thymic carcinomas. Thus, RAGE and HMGB1 are involved in the (patho-)physiology of thymus, as evidenced by differentiated thymic and systemic expression patterns that may act as diagnostic or therapeutic targets in autoimmune disease and cancer.

Good Syndrome, a rare cause of refractory chronic diarrhea and recurrent pneumonia in a Chinese patient after thymectomy

The diagnosis of Good syndrome is very difficult. It has various symptoms, and these symptoms can be present at different periods. In this report we present a patient with refractory chronic diarrhea, recurrent pneumonia, and dysgammaglobulinemia after thymectomy, who was finally then diagnosed with Good syndrome.

Respiratory Tract and Mediastinum

Normal cytology, abnormal and atypical cells, non-cellular components, and infectious cell changes are largely described together with benign, malignant, and neuroendocrine lesions regarding exfoliative and aspiration cytology of the lung. A separate section broadly addresses diagnostic findings and differential diagnoses in bronchoalveolar washings.

The section ‘Fine needle aspiration biopsy of mediastinal disorders’ covers in particular biopsy techniques, accuracy of liquid-based cytology, and the complex lesions of the thymus gland. Cytodiagnostic algorithms of the major benign and malignant pulmonary and mediastinal lesions and their respective differential diagnoses are additionally presented in synoptic setups.

Management of myasthenic patients with thymoma

Myasthenia gravis (MG) associated with thymomas differs from nonthymomatous MG, and thymomas associated with MG are also different from non-MG thymomas. According to the World Health Organization classification, the incidence of MG in thymomas was the highest in the subtypes B2, B1, and AB. Transsternal approach is still regarded as the gold standard for surgical treatment of thymomas. Less-invasive techniques of thymectomy are promising, but it is too early to estimate their real oncological value. In the series including more than 100 patients, the prognosis for survival is better in patients with thymomas associated with MG than in those with non-MG thymomas, and the prognosis for patients with MG associated with thymoma is worse than that for patients with nonthymomatous MG.

Thirty-five-year follow-up analysis of clinical and pathologic outcomes of thymoma surgery

BACKGROUND

The impact of myasthenia gravis on patients with thymoma is still controversial when perioperative and long-term outcomes are analyzed. With the unique opportunity of a 35-year follow-up in a single institution, thymomatous myasthenia gravis cohort, we investigated the influence of early and long-term clinical predictors.

METHODS

We reviewed a surgical series of 317 (1972 to 2007) patients with thymoma: clinical and pathologic features were analyzed as prognostic factors matched against the short- and long-term survival and recurrence rates.

RESULTS

Male to female ratio was 153:164; median age, 49 years. Myasthenia gravis coexisted in 276 patients (87.1%). Thymomas were classified according to the Masaoka (42.0% stage I, 32.2% stage II, 21.5% stage III, and 4.4% stage IV) and the World Health Organization (3.5% type A, 9.5% type AB, 19.2% type B1, 57.7% type B2, 8.2% type B3, and 1.9% thymic carcinoma) staging systems. The resection was complete in 295 patients (93.1%). Operative mortality and morbidity were respectively 1.6% and 7.6%. No differences were recorded in postoperative outcome stratifying for myasthenia gravis or comorbidities. Mean follow-up was 144.7 +/- 104.4 months. The overall 5-, 10-, 20-, and 30-year survival rates were 89.9%, 84.1%, 73%, and 58.6%, respectively. The completeness of resection (p < 0.001), the Masaoka staging (p = 0.010), and the World Health Organization classification (p < 0.001) all significantly influenced the long-term survival (univariate analysis). Only completeness of resection was significantly correlated with a better prognosis (p < 0.001) in multivariate analysis. Masaoka staging (p < 0.001) and World Health Organization classification (p < 0.001) significantly correlated with the disease-free survival in the univariate and multivariate analyses as significant prognostic factors (Masaoka, p < 0.001; World Health Organization, p = 0.011). Myasthenia gravis patients showed a better prognosis in terms of long-term survival (p = 0.046) and disease-free survival (p = 0.012) in the univariate analysis.

CONCLUSIONS

We confirm the evidence that the clinical staging and the histologic classification influence long-term survival. The presence of myasthenia gravis was not significantly related to operative outcome, but prolongs both long-term survival and disease-free survival.

Thymoma: Results of treatment and role of radiotherapy

PURPOSE

The aim of this study is to assess results of treatment, factors influencing prognosis with regard to causes of failure and treatment tolerance in patients with thymoma.

MATERIAL AND METHODS

Between 1966 and 2006, 63 patients with thymoma had been treated at the Centre of Oncology in Krakow. Patients were treated by means of different treatment modalities: surgery followed by radiotherapy (52%), radiotherapy alone (13%), chemoradiotherapy alone (15%), surgery followed by chemoradiotherapy (5%), surgery alone (5%) and others.

RESULTS

The 10-year locoregional recurrence-free survival (LRRFS) was 79%, disease free survival (DFS) was 57% and overall survival (OS) was 57%. Masaoka stage was the only independent prognostic factor for LRRFS. Masaoka stage and method of radiotherapy delivery (higher photon energies), were independent prognostic factors for OS. For DFS, the independent prognostic factors were age, type of treatment (favoured surgery followed by radiotherapy or chemoradiotherapy), Masaoka stage and year of start of treatment. Most common reactions were lung fibrosis in 36% of patients (mainly asymptomatic in most patients), pneumonitis (9%) and oesophagitis (4%).

CONCLUSIONS

Surgery combined with radiotherapy and chemoradiotherapy and modern radiotherapy techniques are correlated with improvement of survival in patients with early stage thymoma.

Good's syndrome remains a mystery after 55 years: A systematic review of the scientific evidence

Good syndrome (GS) is a rare association of thymoma and immunodeficiency first described more than 50 years ago. However, this syndrome still remains a mystery to clinicians. We systematically reviewed all the clinical, laboratory and immunologic findings from 152 patients with Good syndrome. The syndrome has a worldwide distribution and approximately half of the cases (47%) have been described in Europe. The diagnosis of thymoma preceded the diagnosis of hypogammaglobulinemia, infection, or diarrhea in 42% of patients whereas in 38% of patients the diagnoses were made almost simultaneously within 2 months of each other. We found significant mortality in patients with this syndrome (44.5%). Astute clinical acumen and increased awareness about the clinical and immunological profile of this syndrome may increase early recognition of this syndrome and prevent mortality. Further studies are needed to elucidate this clinical entity.

Ectopic thymoma of the lung; a rare case report and review of the literature

Introduction

Ectopic thymoma is a rare neoplasm, which can be developed in various sites, with the lung being amongst the rarest.

Case presentation

In this paper, we present the case of a woman with a slow-growing ectopic thymoma, stemming from the visceral pleura of the upper lobe of the left lung anteriorly, extending into the left lung and the cardiac wall, invading the fatty tissue near the pericardium, notably without infiltrating the lung or cardiac parenchyma. The thymoma was successfully removed via thoracotomy.

Conclusion

Ectopic thymoma is an uncommon neoplasm. To our knowledge, a case of an ectopic thymoma stemming from the visceral pleura of the lung is extremely rare.

Adjuvant radiotherapy for thymic epithelial tumors: a systematic review and meta-analysis

Adjuvant radiotherapy after complete resection of localized, invasive thymic epithelial tumors is considered by many to be the standard of care, despite little supporting literature. We hypothesized that individual studies may lack statistical power to demonstrate a reduction in recurrence with this approach, but meta-analysis of published data may allow for more adequate statistical evaluation. Analysis of data from 592 patients with completely resected stage II or III thymic epithelial tumors, however, revealed no statistically significant reduction in recurrence after adjuvant radiotherapy (odds ratio 1.05; 95% confidence interval: 0.63 to 1.75; p = 0.840). Additionally, the majority of publications suggest that the most common sites of recurrence are the lung, pleura, and diaphragm, even when incompletely resected patients are included.

Treatment of advanced thymoma and thymic carcinoma

Although thymic epithelial tumors are rare, they are relatively common among neoplasms of the anterior superior mediastinum. They usually exhibit indolent behavior, but do have the capacity to invade surrounding structures and metastasize to distant sites. Thymic carcinomas are rare, but are highly aggressive tumors that are associated with a poor prognosis. The mainstay of therapy is complete surgical resection. Locally advanced thymoma and thymic carcinoma require a multimodality treatment approach with a combination of surgery, chemotherapy, and radiation therapy to decrease the chances of recurrence and improve survival. The risk of disease recurrence lasts for a number of years after completion of primary therapy. A majority of cases of recurrent disease present as pleural recurrences. Once again, surgical resection of recurrent disease represents the cornerstone of successful therapy and is critical to long-term survival. In recent years, a better understanding of the biologic basis of thymic epithelial tumors has led to the emergence of targeted therapy directed against this malignancy.

Managing a locally advanced malignant thymoma complicated by nephrotic syndrome: a case report

Introduction

The management of locally advanced inoperable malignant thymoma is difficult as there are no large randomized clinical trial data to guide treatment. However various case series have shown that malignant thymoma is often a chemosensitive disease. Cisplatin-based chemotherapy has been the gold-standard in the management of these patients. However when thymic cancers are complicated by paraneoplastic syndromes that damage kidney and neurological function, cisplatin use is often contraindicated.

Case presentation

We report a case of a 37 year old man with locally advanced malignant thymoma complicated by significant nephrotic syndrome and renal impairment. He responded to a novel combination of carboplatin, epirubicin and cyclophosphamide chemotherapy used as first line therapy.

Conclusion

The treatment with chemotherapy of locally advanced malignant thymoma complicated by nephrotic syndrome and renal impairment is difficult due to the increase of toxicity. In this case, a novel chemotherapy combination with lesser toxicity was used successfully. In addition this chemotherapy combination did not impede the later use of conventional cisplatin-based chemotherapy. Therefore we suggest a course of carboplatin-based chemotherapy for locally advanced malignant thymoma in patients who are unsuitable for cisplatin.

Thymic epithelial neoplasia

Primary thymic epithelial neoplasms (PTENs) are uncommon tumors of anterior mediastinum with a broad range of biological characteristics. We retrospectively reviewed 58 consecutive patients with a diagnosis of PTENs that were confirmed pathologically during 28 yr. There were 58 patients, 31 males (53.4%) and 27 females (46.6%), with a mean age of 43.6 +/-13.8 yr (range, 17-73 yr). Twenty-one (36.2%) patients presented at the Masaoka stage I, 13 (22.4%) patient at stage II, 18 (31.0%) patient at stage III, and 6 (10.4%) patients at stage IV. Forty-five (77.7%) patients had myasthenia gravis, 1 (1.7%) immune deficiency, 1 (1.7%) pancytopenia, and 1 (1.7%) nephrotic syndrome. No paraneoplastic syndrome was associated in 10 (17.2%) patients. Complete resection was accomplished in 41 (70.7%) patients, while incomplete resection was performed in 8 (13.8%) patients. In nine (15.5%) patients only biopsy was carried out. Radiotherapy was administered to 19 (32.8%) patients. Eleven (19.0%) out of 58 who presented at advanced stages (at least III) received chemotherapy. Median follow-up period was 59 mo (range, 1-278 mo). During the follow-up period, 17 deaths occurred. Five patients (29.4%) died of tumor-related causes, and the remaining 12 patients died of other causes (cardiovascular diseases [n = 1, 5.9%], sepsis [n = 4, 23.5%], and MG-related respiratory insufficiency [n = 7, 41.2%]). The overall survival rates at 5 yr and 10 yr were 63.9% and 54.2%, respectively. Tumor-related survival rates at 5 yr and 10 yr were 89.0% and 83.2%, respectively. In our series, disease stage, presence or absence of myasthenia gravis, and tumor size did not affect survival (p> 0.05), either. Complete resection of the tumor seems to be the best predictive factor for long-term survival.

Systemic Treatment of Malignant Thymoma

OBJECTIVES

Thymic malignancies are rare tumors on the superior anterior mediastinum. Treatment of advanced stages includes chemotherapy. The objective of this analysis was to review the treatment of this disease in the past decade.

METHODS

This is a retrospective analysis of the results obtained in a total of 29 patients with advanced malignant thymomas who underwent systemic chemotherapy in the past 10 years at our institution. Sixteen received neoadjuvant chemotherapy in the attempt to shrink the tumor and then perform a radical operation. The others received chemotherapy as palliation. Platinum based chemotherapy was mainly used.

RESULTS

The response rate to first-line chemotherapy was 50% in the neoadjuvant setting and 31% in the advanced setting. A better survival was observed in patients who underwent chemotherapy as part of their combined modality treatment, in patients with thymomas, and in patients without visceral metastases. Some patients responded to targeted therapies at relapse.

CONCLUSIONS

A better understanding of the biology of this rare tumor may allow in the future the development of better therapies for the more aggressive tumor types (WHO type C), which appear to be increasing in frequency.

Mediastinum thymoma diagnosed by FNA and ThinPrep technique: a case report

Thymoma is a primary tumor of the thymus epithelial cells. It may be asymptomatic or accompanied with atypical clinical symptoms or paraneoplastic syndromes, such as myasthenia gravis. The biological behavior of thymomas is unpredictable. The invasion of the capsule or the adjacent tissues is the major diagnostic criterion for the malignant behavior of these tumors. This is an interesting case of thymoma diagnosed by fine-needle aspiration biopsy (FNA) and ThinPrep technique, in a 54-year-old female patient with a history of gastric adenocarcinoma. Cytology of the mediastinum mass revealed a mixed population of epithelial cells and lymphocytes. The tumor was excised and the histopathological examination supported the cytological diagnosis. Thymomas commonly constitute a problem in differential diagnosis of mediastinum masses. FNA biopsy in correlation with ThinPrep technique and immunocytochemistry may play a significant role in clarifying the nature of these lesions and may contribute to the early management and choice of the optimal therapeutic manipulation.

Tumeurs épithéliales thymiques

Thymomas and thymic carcinomas are rare and slow-growing tumors, which develop within the anterior mediastinum. Thymomas are often associated with autoimmune disorders and most particularly myasthenia gravis. The treatment of choice remains a complete surgical resection. Postoperative radiotherapy is often combined in case of invasive thymoma invading into adjacent organs. Postoperative radiotherapy in stage II with invasion into capsule has been more controversial lately. In inoperable locally advanced, or metastatic thymic tumors, neoadjuvant cisplatin-based followed by surgery and radiotherapy has given interesting results in the past years.

Malignant thymoma complicated by amegakaryocytic thrombocytopenic purpura

We report the case of a 41-year-old man with malignant thymoma complicated by amegakaryocytic thrombocytopenia 10 years after diagnosis of myasthenia gravis. A bone marrow aspirate showed an absence of megakaryocytes with normal maturation and differentiation of myeloid precursors. Three months later, severe neutropenia occurred, and a bone marrow examination confirmed the diagnosis of severe aplastic anemia. Associations between thymoma and myasthenia gravis, between thymoma and pure red cell aplasia, and between thymoma and aplastic anemia are well documented. Amegakaryocytic thrombocytopenia is not a recognized paraneoplastic syndrome complicating thymoma. Amegakaryocytic thrombocytopenia complicating thymoma may be a very early presentation of impending aplastic anemia.

Recurrent bilateral exophthalmos associated with metastatic thymic carcinoma in a pet rabbit

A five-year-old, castrated, male chinchilla rabbit was presented for evaluation of recurrent bilateral exophthalmos. Besides a transient and stress-related exophthalmos with protrusion of both third eyelids, the ophthalmological examination was unremarkable. Plain radiography of the thorax revealed a large precardial mass of soft tissue density. Cytological preparations from the thoracic mass were dominated by small, mature lymphocytes with approximately 10 to 20 per cent lymphoblasts. Computed tomography of the head showed a symmetrical laterodorsal deviation of both eyes without evidence of retrobulbar masses. On necropsy a large cystic mass was present in the cranial thorax associated with severe hydrothorax, hydropericardium and ascites. Histology identified the precardial mass as thymic carcinoma with metastases in the kidneys. This case illustrates the difficulty of diagnosing thymic tumours based on cytological or histological features of the primary tumour alone. To the authors' knowledge, this is the first case of recurrent bilateral exophthalmos associated with a metastatic thymic carcinoma in a pet rabbit.

Advanced Stage Thymomas and Thymic Carcinomas: Results of Multimodality Treatments

BACKGROUND

With the aim of evaluating the results of multidisciplinary approaches, we reviewed our experience in multimodality treatment of advanced stage (III and IVA) thymic tumors.

METHODS

From 1976 to 2003, 56 patients with Masaoka stage III and IVA thymic tumors underwent a multimodality treatment. Thirty-six patients underwent neoadjuvant chemotherapy, surgery, and postoperative radiotherapy; 20 patients were treated by primary surgery and postoperative radiotherapy (n = 12), chemotherapy (n = 1) or chemoradiotherapy (n = 7). The neoadjuvant or adjuvant chemotherapy consisted of three courses of cisplatin, epidoxorubicin, and etoposide every 3 weeks. Adjuvant radiotherapy consisted of 45 Gy for complete resections or 60 Gy for incomplete resections.

RESULTS

The preoperative diagnosis of invasive thymomas was performed in a total of 29 cases: 15 by mediastinotomy, 6 by video-assisted thoracoscopic surgery, and 8 by fine-needle aspiration. In 27 cases no diagnosis was available, but in most of them a thymus-related syndrome was present. Thirty-four patients are still alive (31 disease-free), and 22 have died (2 disease-free). Ten-year survival was 48% and 45.7% for stage III and IVA thymomas, respectively. The presence of myasthenia gravis (p = 0.04) and neoadjuvant chemotherapy (p = 0.004) affected survival significantly.

CONCLUSIONS

The multimodality treatment of stage III and IVA thymic tumors allows a good long-term outcome; the neoadjuvant chemotherapy improves the resectability rate and the survival of both stages of the disease.

Treatment of malignant thymoma

PURPOSE OF REVIEW

The present review reports findings in the field of epithelial tumors originating from the thymus from the past year and discusses these findings in the context of the literature.

RECENT FINDINGS

Epithelial tumors of the thymus are relatively common tumors of the anterior superior mediastinum. Thymomas are usually slowly growing tumors, and their prognosis depends on the macroscopic and microscopic invasion of surrounding tissues. Thymic carcinomas are more aggressive and less common tumors than thymomas and have been increasing in frequency in recent years. Surgery is the mainstay treatment of thymic malignancies, and complete resection represents the best prognostic factor in this disease. Postoperative radiotherapy may be indicated in tumors with invasion of surrounding tissues, but it is controversial in early-stage thymomas. Combination chemotherapy has been employed in several small studies and in advanced disease has been demonstrated to produce a 50-80% objective response rate. Neoadjuvant chemotherapy or external beam radiotherapy have been used with success in patients with tumors that are not readily resectable. Novel antiproliferative systemic agents are being investigated, based on a better understanding of the biology of these tumors.

SUMMARY

A better understanding of the clinical behavior of thymomas versus thymic carcinomas and systemic therapies targeted to biologically validated targets in these diseases will help improve efficacy of treatment.

Multimodality Treatment Program in Invasive Thymic Epithelial Tumor

Little is known regarding malignant thymoma and thymic carcinoma optimal therapy, and a multimodality approach could therefore be proposed in an attempt to improve the survival of patients. We report our experience with 8 cases of malignant thymoma or thymic carcinoma. These patients took part in a multimodality treatment program including neoadjuvant chemotherapy, surgery, and postoperative radiotherapy in our center between December 1995 and June 2001. The induction chemotherapy consisted of 4 courses of the CAP regimen (cyclophosphamide 600 mg/m2 day 1, doxorubicin 50 mg/m2 day 1, and cisplatin 80 mg/m2 day 2), every 3 weeks. Patients underwent surgical resection after complete hematological recovery pending sufficient tumor response with a postchemotherapy resectable status. Adjuvant radiotherapy up to 60 Gy in 30 fractions was attempted postsurgically or after best chemotherapeutic response in nonsurgical patients. Among the 8 patients, 3 had a thymic carcinoma and 5 a malignant thymoma; 5 had a stage IV and 3 a stage III disease (Masaoka). Six patients partially responded to the chemotherapy regimen. Three patients were operated upon, and complete resection was performed in 2 cases. Finally, 4 patients achieved the planned radiotherapy. Four patients are still alive without evidence of tumor activity (23-77 months from the diagnosis) and 1 patient is alive with relapse at 56 months. The low compliance with the program led us to an early discontinuation. The high proportion of thymic carcinoma and advanced disease in our limited series might be an explanation for this unsatisfactory result. Optimal multimodality treatment of epithelial thymic tumor remains to be defined in multicenter trials.

Radiotherapy and prognostic factors for thymoma: A retrospective study of 175 patients

PURPOSE

To assess the factors that predict local control and survival in patients with thymoma treated with adjuvant radiotherapy (RT) and suggest strategies for optimizing adjuvant RT.

METHODS AND MATERIALS

The study population comprised 47 patients with noninvasive thymoma and 128 patients with invasive thymoma. Treatment was surgery in 175 patients and radiotherapy in 169 patients; 25 patients also received adjuvant chemotherapy. The clinical factors (age, histologic features, stage, presence of myasthenia gravis) and therapeutic factors (extent of operation, irradiation dose, and field size) were retrospectively recorded and accessed using multivariate analysis.

RESULTS

The overall survival rate at 5 and 10 years was 86.4% and 80.6%, respectively. Only 2 patients had a relapse in the noninvasive group. None died of thymoma during the study period. The patients with invasive disease had a 5- and 10-year disease-free survival rate of 64.4% and 55.6%, respectively, with 24 intrathoracic failures, 14 extrathoracic failures, and 8 combined failures. The univariate and multivariate analyses showed that Mosaoka stage and extent of resection were the important prognostic factors for patient with invasive thymoma. The 5-year survival rate and local control rate was 96% and 96% for Stage II, 77.8% and 56.4% for Stage III, 56.6% and 42.7% for Stage lVa, and 35.6% and 21.6% for Stage IVb (p < 0.0001 among different stage groups), respectively. The 5-year local control rate in patients with the tumor bed irradiated was 68.2%, comparable to the group treated with an extended RT field (66.6%). Age, histopathologic findings, radiation dose, and presence of myasthenia gravis were not statistically significant prognostic factors.

CONCLUSION

Disease stage and extent of resection affected the prognosis of invasive thymoma patients. Extending the radiation field prophylactically was not associated with greater local control and is of questionable value for patients with invasive thymoma.

Treatment of thymoma: a comparative study between Thailand and the United States and a review of the literature

This article provides a unique perspective on thymoma by describing the clinical scenarios from 2 diverse patient populations followed by an update. A comparative chart review was conducted on patients diagnosed at 2 university-based hospitals, 1 in the United States and 1 in Thailand. A comprehensive review of the literature was then performed through MEDLINE for articles between 1980 and 2002. During the last 23 years, charts from 16 patients at each institution were available for review. The most common presenting symptoms were myasthenia gravis (47%), dyspnea (25%), and chest discomfort (19%) and are similar to those reported in the literature. The primary treatment of stages I-III disease included surgery with or without radiation. Trimodality therapy with surgery, radiotherapy, and chemotherapy was pursued in 43% of patients with stage IV disease in the United States, whereas no patients from Thailand underwent this regimen. Median overall survivals were 124 and 76 months in the Thai and the US groups, respectively (P = 0.76). No major differences in the clinical features were observed between the 2 institutions, although a trend toward more advanced disease was seen in the United States. Surgery and radiation remain the backbone of treatment, but the role for chemotherapy is increasing.

Thymic carcinoma: state of the art review

Thymic carcinoma is a rare neoplasm with distinct clinical and pathological characteristics. The prognosis is often poor with an aggressive course that belies its numerical rarity. Potentially prognostic factors for survival include histopathologic grade, clinical stage, and resectability of the tumor. Five-year survival rates for all patients are approximately 30-50%, with a significant survival time differential between low-grade and high-grade neoplasms. Owing to the paucity of cases, optimal management of thymic carcinoma has yet to be defined. At present, a multimodality approach involving aggressive surgical resection, platinum-based combination chemotherapeutic interventions, and radiotherapy represent the preferred therapeutic approach. Though our knowledge remains somewhat speculative at present, several scientific, technological and therapeutic innovations may have a potentially significant impact on the future of this disease.

Thymoma and myotonic dystrophy: successful treatment with chemotherapy and radiation: case report and review of the literature

We present the case of a 42-year-old woman with myotonic dystrophy and thymoma. She was treated with combination chemotherapy followed by external beam radiation, and remains in remission 19 months after thymoma was diagnosed. The myotonic dystrophy is unchanged. Only six cases of this nature have been reported in the literature, and this patient is the first to be successfully treated with combined modality therapy.