Key Points

• This chapter will discuss mesenchymal tumors, primary mediastinal carcinoma, and Castleman’s Disease, all rare tumours not covered elsewhere in the book.
• Literature is largely based on case reports and case series.
• Castleman’s disease is perhaps the most frequently seen of these rare mediastinal tumours in adults.
• There is no universally accepted classification system; however, we offer in Table 1 an attempt to unify and summarize the available information about this heterogeneous collection of lesions.
• CT or MRI may be useful in diagnosis. However, tissue diagnosis is often required to make the definitive diagnosis.
• Resection is the treatment of choice as chemotherapy and radiation are often not effective.
• In occasional cases it is wise to onsider pre-operative embolization for some solitary fibrous tumors, hemangiomas and Castleman’s disease.
• Prognosis is variable and dependent on histology and completeness of resection.