<unk> , also known as type C thymoma, is a rare condition (less than 0.13/100,000/year) but should be included in the differential diagnosis of anterior mediastinic masses. It is a tumor of the<unk>  epithelium, like thymoma,  but it is associated with lack of immature lymphocytes and often presents with more invasive or metastatic disease.<unk> s can metastasize, generally to pleura, kidney, bone, liver, or brain. The<unk>  is a tumor of the<unk>  epithelium, but it is associated with lack of immature lymphocytes and often presents with more invasive or metastatic disease. The pathophysiology of<unk>  depends on the histological subtype. On microscopic histopathological analysis,<unk>  is divided into squamous cell<unk> , basaloid<unk> , mucoepidermoid<unk> , lymphoepithelioma-like<unk> , sarcomatoid<unk>  <unk> rcoma),  clear cell<unk> , papillary adenocarcinoma,<unk>  with t(15;19) translocation, neuroendrocrine<unk> s, undifferentiated<unk> , and combined<unk>  epithelial tumors.<unk>  has not been reported in association with myasthenia gravis, in contrast with thymoma. The cause of<unk>  has not been identified. The most common differential diagnosis of<unk>  is thymoma, which is the most common pathology of the thymus.<unk>  must be differentiated from other mediastinal masses such as germ cell tumors, lymphoma, thyroid tumors, and metastatic<unk>  to the mediastinal lymph nodes. The prevalence of<unk>  is approximately 0.00006 per 100,000 individuals worldwide. Males are more commonly affected with<unk>  than females. The male to female ratio is approximately 3 to 1. It is more common in Asians and African Americans than in Caucasians. There are no established risk factors for<unk> .<unk> s are generally considered indolent tumors due to the long recurrence intervals (median of 68 months). The most common sites of distant recurrence are lung, liver, bone, kidney, brain and bone marrow. The most important factor for prognosis is the stage and grade of the<unk> . The 5-year and 10-year overall survival rates in patients with<unk>  are 38% and 28% respectively. The subtypes squamous cell<unk> , mucoepidermoid<unk> , and basaloid<unk>  have a better prognosis than other histological subtypes. The staging of<unk>  is based on the Masoka and GETT staging system. Symptoms of<unk>  include dull chest pain, cough, dyspnea, and constitutional symptoms. Chest CT scan may be helpful in the diagnosis of<unk> . On CT scan of the chest,<unk>  is characterized by lobulated mass with irregular borders, heterogeneous attenuation, and mediastinal fat invasion with areas of necrosis, hemorrhage, calcification, or cyst formation. Chest MRI scan may be diagnostic of<unk> . Findings on chest MRI suggestive of<unk>  include isointense to slightly hyperintense signal compared to muscle on T1 weighted image and heterogeneous signal on T2 weighted image. On T1 weighted image with gadolinium contrast, linear regions of enhancement may be observed coursing through the mass, which are thought to represent fibrous septae. Other imaging studies for the diagnosis of<unk>  include FDG PET scan. The standarized uptake value (SUV) in the FDG PET is much higher for the<unk>  than thymoma, with a high sensitivity (84.6%) and specificity (92.3%). Other diagnostic studies for<unk>  include immunohistochemistry. The predominant therapy for<unk>  is surgical resection. Adjunctive cisplatin-basedchemotherapy may be required. Surgery is the mainstay of treatment for<unk> . There is no established method for primary prevention of<unk> . There are no secondary preventive measures available for<unk> .
Thymic carcinoma
Nodal marginal zone lymphoma
Silent thyroiditis
Follicular lymphoma
B-cell lymphoma
Primary thyroid lymphoma
Anaplastic thyroid cancer
T-cell lymphoma