Gray Zone Lymphoma: Current Diagnosis and Treatment Options.

The morphology of gray zone lymphoma (GZL) is variable with tumor cells spanning the spectrum of diffuse large B-cell lymphoma (DLBCL) and classical Hodgkin lymphoma. The immunophenotype is frequently discordant. Clinically, the initial case descriptions of GZL were primarily with mediastinal presentation; however, a nonmediastinal (systemic) clinical subtype is now recognized. Patients with GZL have high relapse rates. Recommended treatment of GZL is with a DLBCL-directed regimen with consideration for consolidative radiotherapy for bulk disease. Continued biologic examination of this entity is needed and there should be exploration toward integration of novel targeted therapeutic agents into the treatment paradigm of GZL.