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Pediatric Thymoma Differential Diagnoses

  • Author: Richard A Bickel, MD; Chief Editor: Harumi Jyonouchi, MD  more...
Updated: Mar 21, 2016

Diagnostic Considerations

Other medical problems associated with thymomas include the following:[15, 13]

  • Dermatomyositis
  • Polymyositis
  • Autoimmune thyroiditis
  • Pernicious anemia
  • Scleroderma
  • Rheumatoid arthritis
  • Raynaud phenomenon
  • Regional enteritis
  • Diabetes
  • Amyloidosis
  • Chronic hepatitis
  • Cushing syndrome
  • Addison disease
  • Undifferentiated thymic carcinoma (found to be associated with Epstein-Barr virus in a 12-year-old girl)[11]

Other abnormal growths of the anterior mediastinum include thymic cysts or thymic carcinoma (also referred to as malignant thymoma).

Other mediastinal masses in the differential diagnosis include the following:[15]

  • Thymolipoma
  • Mediastinal germ cell tumor
  • Mediastinal lymphangioma (rare tumors that predominantly occur in children)
  • Mediastinal goiter
  • Mediastinal parathyroid adenomas (uncommon and rarely cause a discernible mass)

Levels of serum beta-subunit human chorionic gonadotrophin (beta-HCG) or alpha-fetoprotein (AFP) may be elevated in germ cell tumors.

Differential Diagnoses

Contributor Information and Disclosures

Richard A Bickel, MD Chief, Allergy Clinic, Moncrief Army Community Hospital

Richard A Bickel, MD is a member of the following medical societies: American Academy of Allergy Asthma and Immunology, American Academy of Pediatrics, American College of Allergy, Asthma and Immunology

Disclosure: Nothing to disclose.


Cecilia P Mikita, MD, MPH Associate Program Director, Allergy-Immunology Fellowship, Associate Professor of Pediatrics and Medicine, Uniformed Services University of the Health Sciences; Staff Allergist/Immunologist, Walter Reed National Military Medical Center

Cecilia P Mikita, MD, MPH is a member of the following medical societies: American Academy of Allergy Asthma and Immunology, American College of Allergy, Asthma and Immunology

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

David J Valacer, MD 

David J Valacer, MD is a member of the following medical societies: American Academy of Allergy Asthma and Immunology, American Academy of Pediatrics, American Association for the Advancement of Science, American Thoracic Society, New York Academy of Sciences

Disclosure: Nothing to disclose.

Chief Editor

Harumi Jyonouchi, MD Faculty, Division of Allergy/Immunology and Infectious Diseases, Department of Pediatrics, Saint Peter's University Hospital

Harumi Jyonouchi, MD is a member of the following medical societies: American Academy of Allergy Asthma and Immunology, American Academy of Pediatrics, American Association of Immunologists, American Medical Association, Clinical Immunology Society, New York Academy of Sciences, Society for Experimental Biology and Medicine, Society for Pediatric Research, Society for Mucosal Immunology

Disclosure: Nothing to disclose.

Additional Contributors

Terry W Chin, MD, PhD Associate Clinical Professor, Department of Pediatrics, University of California, Irvine, School of Medicine; Associate Director, Cystic Fibrosis Center, Attending Staff Physician, Department of Pediatric Pulmonology, Allergy, and Immunology, Memorial Miller Children's Hospital

Terry W Chin, MD, PhD is a member of the following medical societies: American Academy of Allergy Asthma and Immunology, American Association of Immunologists, American College of Allergy, Asthma and Immunology, American College of Chest Physicians, American Federation for Clinical Research, American Thoracic Society, California Society of Allergy, Asthma and Immunology, California Thoracic Society, Clinical Immunology Society, Los Angeles Pediatric Society, Western Society for Pediatric Research

Disclosure: Nothing to disclose.


The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous author Marion Johnson, MD, to the development and writing of this article.

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Table 1. Comparison of the Different Classifications of Thymic Epithelial Tumors[27]
Clinicopathologic ClassificationWHO TypeTerminology of the Histogenetic Classification for the Histologic Subtypes of Thymic Epithelial Tumors
Benign thymomaA


Medullary thymoma

Mixed thymoma

Malignant thymomas,

Category I




Predominantly cortical thymoma

Cortical thymoma

Well-differentiated thymic carcinoma

Malignant thymomas,

Category II

CEpidermoid keratinizing (squamous cell) carcinoma

Epidermoid nonkeratinizing carcinoma

Lymphoepithelioma-like carcinoma

Sarcomatoid carcinoma (carcinosarcoma)

Clear cell carcinoma

Mucoepidermoid carcinoma

Undifferentiated carcinoma

Table. Macchiarini et al (1991)[38]
Cisplatin75 mg/m2 on day 13 courses repeated q3wk
Epirubicin100 mg/m2 on day 1
Etoposide120 mg/m2 on days 1, 3, and 5
Surgery and radiation

in patients with

complete or partial

response to chemotherapy

4500 cGy if complete


6000 cGy if incomplete


Table. Loehrer et al (1997)[39]
Cisplatin50 mg/m22-4 cycles q3wk
Doxorubicin50 mg/m2
Cyclophosphamide500 mg/m2
Followed by radiation54 Gy to the primary tumor and lymph nodes
Table. Venuta et al (1997)[40]
Cisplatin75-100 mg/m2 on day 1Repeated q3wk 3 times before surgery and 2 or 3 times after surgery
Epirubicin hydrochloride100 mg/m2 on day 1
Etoposide120 mg/m2 on days 1, 3, and 5
Postoperative radiation in patients with radical resection30 GyDelivered in 3 wk with 5 fractions per wk
Postoperative radiation in

patients with incomplete resection

50 GyDelivered in 5 wk with 5 fractions per wk
Table. Palmieri et al (1999)[42]
Octreotide1.5 mg/d SCIn patients shown to have

somatostatin receptors

Lanreotide30 mg/d SC q14dSwitch to this longer-acting

somatostatin analogue or depot form of octreotide if short-acting octreotide

is well tolerated

Prednisone0.6 mg/kg/d PO

for 3 mo, then

decreasing to 0.2 mg/kg

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