Thymic carcinoma is part of the malignant end of thymic epithelial tumours.
Patients are typically 50 to 70 years of age at presentation 9.
The incidence of paraneoplastic syndromes is thought to be low. At least 10 different histologic variants have been described 4. The most common subtypes are squamous cell carcinoma and lymphoepithelial-like carcinoma 1.
Labelled as "type C" under the WHO classification scheme for thymic epithelial tumours.
Useful features for differential from more benign thymic epithelial tumours include 1:
- larger 5 and highly aggressive anterior mediastinal mass
- areas of necrosis, haemorrhage, calcification, or cyst formation
- gross invasion of contiguous mediastinal structures and wide spread to involve distant intrathoracic sites
- high incidence of extrathoracic metastases
FDG PET-CT may be useful in differentiating thymic carcinoma from other thymic neoplasms, thymic hyperplasia, and normal physiologic uptake. The standardized uptake value (SUV) for thymic carcinoma is considered to be significantly greater than that for invasive or noninvasive thymoma, often with an SUV cutoff point of 5.0, thymic carcinoma can be differentiated from thymoma with reasonably high sensitivity (84.6%), specificity (92.3%), and accuracy (88.5%) 6.
Treatment and prognosis
They are often associated with a poor prognosis.
For an invasive anterior mediastinal mass lesion consider:
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- 7- Nasseri F, Eftekhari F. Clinical and radiologic review of the normal and abnormal thymus: pearls and pitfalls. Radiographics. 2010;30 (2): 413-28. Radiographics (full text) - doi:10.1148/rg.302095131 - Pubmed citation
- 8- Do YS, Im JG, Lee BH et-al. CT findings in malignant tumors of thymic epithelium. J Comput Assist Tomogr. 1995;19 (2): 192-7. Pubmed citation
- 9- Lee JD, Choe KO, Kim SJ et-al. CT findings in primary thymic carcinoma. J Comput Assist Tomogr. 1991;15 (3): 429-33. Pubmed citation