8580/1 Thymoma, NOS


Definitions

Bronchus and lung
ICD-O-3 topography code: C34

A neoplasm arising from the epithelial cells of the thymus. Although thymomas are usually encapsulated tumors, they may invade the capsule and infiltrate the surrounding tissues or even metastasize to distant anatomic sites. The following morphologic subtypes are currently recognized: type A, type B, type AB, metaplastic, micronodular, microscopic, and sclerosing thymoma. Thymomas type B are further subdivided into types B1, B2, and B3. Thymoma type B3 usually has the most aggressive clinical course.



Thymus
ICD-O-3 topography code: C37

A neoplasm arising from the epithelial cells of the thymus. Although thymomas are usually encapsulated tumors, they may invade the capsule and infiltrate the surrounding tissues or even metastasize to distant anatomic sites. The following morphologic subtypes are currently recognized: type A, type B, type AB, metaplastic, micronodular, microscopic, and sclerosing thymoma. Thymomas type B are further subdivided into types B1, B2, and B3. Thymoma type B3 usually has the most aggressive clinical course.



Thyroid gland
ICD-O-3 topography code: C73

A neoplasm arising from the epithelial cells of the thymus. Although thymomas are usually encapsulated tumors, they may invade surrounding tissues or even metastasize to distant anatomic sites. The following morphologic subtypes are currently recognized: type A, type B, type AB, metaplastic, micronodular, microscopic, and sclerosing thymoma. Thymomas type B are further subdivided into types B1, B2, and B3. Thymoma type B3 usually has the most aggressive clinical course 1
 
Travis WD, Brambilla E, Müller-Hermelink HK, Harris CC (Eds.)
World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Lung, Pleura, Thymus and Heart.
3rd Edition
IARC Press: Lyon 2004



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Ectopic thymoma only rarely occurs within the thyroid gland
2
Click to access Pubmed
Chan JK, Rosai J (1991)
Tumors of the neck showing thymic or related branchial pouch differentiation: a unifying concept.
Hum Pathol 22: 349-67



3
Click to access Pubmed
Martin JM, Randhawa G, Temple WJ (1986)
Cervical thymoma.
Arch Pathol Lab Med 110: 354-7



. Most patients are middle-aged, with a strong female predominance. Thyroid thymoma usually does not recur after surgical excision 4
 
Ronald A. DeLellis, Ricardo V. Lloyd, Philipp U. Heitz, Charis Eng
World Health Organization Classification of Tumours. Pathology and Genetics of Tumors of Endocrine Organs
IARC Press: Lyon 2004



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