Review
Thymomas: Review of Current Clinical Practice

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Thymomas are the most common tumors of the mediastinum. The introduction of multimodality treatment strategies, as well as novel approaches to the diagnosis of these tumors, has led to changes in the clinical management of thymomas. Here we review the literature for current clinical practice in the diagnosis, management, and treatment of thymomas.

Section snippets

Classification of Thymomas

Several classification systems of thymomas have been developed and described. However, clinical, pathologic, and surgical classification of thymomas remains controversial. The histomorphologic variability and heterogeneity of cells within thymomas is a major factor guiding this intense debate [8, 9, 10, 11]. The most commonly used classification systems are summarized in Table 1.

In 1961, Bernatz and colleagues [12] described thymomas according to their dominant cell type: predominantly spindle

Methods

To determine the state of the art in thymoma therapy, prognostic factors, and outcome, we searched the PubMed database for “thymoma” (with 6,981 hits listed). Only abstracts published in English were considered, and clinical studies with a case load with greater than 100 patients (n > 100) were selected for complete review. As no large prospective studies have been conducted as yet, all reviewed studies were retrospective. Due to the lack of larger studies evaluating diagnostic methods and the

Patient Characteristics

Twenty-eight studies that include 5,487 patients overall diagnosed with thymoma were identified, reviewed, and analyzed. Within these studies, patients' median age ranged from 45 to 59.5 years with an average follow-up of 95.2 months.

Applying the Masaoka staging system, 36% of all study patients had a stage I thymoma, 26% were stage II, 22% were stage III, and 10% were stage IV. Applying the World Health Organization classification system, 8% were type A, 26% were type AB, 15% were type B1, 28%

Radiological Imaging

Currently, computed tomography is the first choice technique to characterize a mediastinal mass with regard to its anatomic dissemination and invasion of neighboring structures, as well as possible distant metastases. Chest roentgenograms show merely a nonspecific broadened mediastinum [31], as shown and represented in Figure 1. Applying computed tomography, thymomas can often be distinguished from benign mediastinal lesions or from lymphoma in the case of multiple mediastinal abnormalities [32

Surgery

As the only curative treatment, surgery remains the baseline attempt in thymoma therapy. Complete or partial median sternotomy with complete thymectomy is the operative approach of choice [22, 23, 26, 46, 47, 48, 49], as first described by Blalock in 1941 [50]. In advanced tumors, especially if the lung or pleural space is invaded, the extension of a sternotomy to a hemi-clamshell incision or a full clamshell incision can be suitable. Approaches like transcervical and video-assisted

Comment

In summary, the Masaoka staging system seems to be the current state of the art in thymoma diagnostics and therapy. Computed tomography is the diagnostic tool of choice to image the mediastinal lesion and its anatomical extent. For histopathologic diagnosis, especially if the lesion is invading the neighboring structures, a preoperative specimen acquisition by FNA or core biopsy should be considered, especially if neoadjuvant therapy is considered.

Median sternotomy is the surgical approach of

References (78)

  • A. Larghi et al.

    EUS-guided fine needle tissue acquisition by using high negative pressure suction for the evaluation of solid masses: a pilot study

    Gastrointest Endosc

    (2005)
  • J.F. Regnard et al.

    Prognostic factors and long-term results after thymoma resection: a series of 307 patients

    J Thorac Cardiovasc Surg

    (1996)
  • C.D. Wright et al.

    Induction chemotherapy followed by resection for locally advanced Masaoka Stage III and IVa thymic tumors

    Ann Thorac Surg

    (2008)
  • G. Zhu et al.

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

    Int J Radiat Oncol Biol Phys

    (2004)
  • A. Aubert et al.

    Video-assisted extended thymectomy in patients with thymoma by lifting the sternum: is it safe?

    Ann Thorac Surg

    (2004)
  • M.K. Ferguson

    Transcervical thymectomy

    Semin Thorac Cardiovasc Surg

    (1999)
  • Y.J. Cheng et al.

    Videothoracoscopic resection of stage II thymoma: prospective comparison of the results between thoracoscopy and open methods

    Chest

    (2005)
  • K. Kondo et al.

    Therapy for thymic epithelial tumors: a clinical study of 1,320 patients from Japan

    Ann Thorac Surg

    (2003)
  • A.A. Mangi et al.

    Adjuvant radiation of stage III thymoma: is it necessary?

    Ann Thorac Surg

    (2005)
  • J.A. Cesaretti

    Adjuvant radiation with modern techniques is the standard of care for stage III thymoma

    Ann Thorac Surg

    (2006)
  • C. Sugie et al.

    Invasive thymoma: postoperative mediastinal irradiation, and low-dose entire hemithorax irradiation in patients with pleural dissemination

    J Thorac Oncol

    (2008)
  • S. Bretti et al.

    Multimodal management of stages III-IVa malignant thymoma

    Lung Cancer

    (2004)
  • M. Lucchi et al.

    Advanced stage thymomas and thymic carcinomas: results of multimodality treatments

    Ann Thorac Surg

    (2005)
  • E.S. Kim et al.

    Phase II study of multidisciplinary approach with induction chemotherapy, followed by surgical resection, radiation therapy, and consolidation chemotherapy for unresectable malignant thymomas: final report

    Lung Cancer

    (2004)
  • J. Huang et al.

    Multimodality therapy for locally advanced thymomas: state of the art or investigational therapy?

    Ann Thorac Surg

    (2008)
  • K. Kondo et al.

    Thymoma and myasthenia gravis: a clinical study of 1,089 patients from Japan

    Ann Thorac Surg

    (2005)
  • F. Romi et al.

    Titin and ryanodine receptor epitopes are expressed in cortical thymoma along with costimulatory molecules

    J Neuroimmunol

    (2002)
  • C. Hon et al.

    Thymoma associated with keratoconjunctivitis, lichen planus, hypogammaglobinemia, and absent circulating B cells

    J Clin Oncol

    (2006)
  • S. Miyakis et al.

    Thymoma with immunodeficiency (Good's syndrome): review of the literature apropos three cases

    Scand J Infect Dis

    (2006)
  • T. Murakawa et al.

    Thymoma associated with pure red-cell aplasia: clinical features and prognosis

    Asian Cardiovasc Thorac Ann

    (2002)
  • G.O. Skeie et al.

    Guidelines for the treatment of autoimmune neuromuscular transmission disorders

    Eur J Neurol

    (2006)
  • E.A. Engels et al.

    Malignant thymoma in the United States: demographic patterns in incidence and associations with subsequent malignancies

    Int J Cancer

    (2003)
  • G. Chen et al.

    New WHO histologic classification predicts prognosis of thymic epithelial tumors: a clinicopathologic study of 200 thymoma cases from China

    Cancer

    (2002)
  • N.L. Harris et al.

    Thymoma classification: a siren's song of simplicity

    Am J Clin Pathol

    (1999)
  • M.J. Kornstein

    Thymoma classification: my opinion

    Am J Clin Pathol

    (1999)
  • S. Suster et al.

    Thymoma classificationThe ride of the valkyries?

    Am J Clin Pathol

    (1999)
  • T.T. Kuo

    Classification of thymic epithelial neoplasms: a controversial issue coming to an end?

    J Cell Mol Med

    (2001)
  • J. Rosai et al.

    Tumors of the thymusAtlas of Tumor Pathology 2nd series, Fasc 13

    (1976)
  • M. Marino et al.

    Thymoma and thymic carcinoma: Relation of thymoma epithelial cells to the cortical and medullary differentiation of thymus

    Virchows Arch A Pathol Anat Histopathol

    (1985)
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