Clinical and pathological diagnosis of peripheral T-cell lymphoma and emerging treatment options: A case-based discussion.

The diverse group of peripheral T-cell lymphomas (PTCLs) present clinical and pathologic challenges. Proper recognition and diagnosis can be difficult even for experienced pathologists because these entities tend to vary in morphologic appearance from case to case within the same subtype and often mimic other diseases in appearance. This makes the use of immunologic markers an essential tool. Clinically, PTCLs are difficult to treat because they often present in an advanced stage and are resistant to traditional first-line chemotherapeutic regimens. Five-year overall survival rates are dismal, ranging from 20-50%, depending upon subtype. Although high-dose sequential chemotherapy followed by autologous hematopoietic stem cell transplantation has been reported to improve overall survival in patients with PTCL, this therapy is only feasible for the small minority of patients who experience a durable complete response to induction therapy. Therefore, there is much interest in the field in developing novel first-line approaches that will improve response rates and duration. In this monograph, 2 case studies of different subtypes of PTCL will be presented, and the clinical and pathologic features will be discussed. In addition, data on emerging therapies for PTCLs will be reviewed with an emphasis on novel and investigational agents.