thymic carcinoma

Thymic carcinoma is part of the malignant end of thymic epithelial tumors.

Epidemiology

Patients are typically 50 to 70 years of age at presentation .

Pathology

The incidence of paraneoplastic syndromes is thought to be low. At least 10 different histologic variants have been described . The most common subtypes are squamous cell carcinoma and lymphoepithelial-like carcinoma .

Classification

Labeled as "type C" under the WHO classification scheme for thymic epithelial tumors.

Radiographic features

CT

Useful features for differential from more benign thymic epithelial tumors include :

  • larger and highly aggressive anterior mediastinal mass
  • areas of necrosis, hemorrhage, calcification, or cyst formation
  • gross invasion of contiguous mediastinal structures and wide spread to involve distant intrathoracic sites
  • high incidence of extrathoracic metastases
Nuclear medicine

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%) .

Treatment and prognosis

They are often associated with a poor prognosis.

Differential diagnosis

For an invasive anterior mediastinal mass lesion consider:

  • aggressive mediastinal germ cell tumor
  • primary mediastinal lymphoma with invasive spread: lack infiltration
  • lung cancer with mediastinal invasion