ABSTRACT
Checkpoint inhibitors, cancer immunotherapies, are the new forms of treatment for gray zone lymphoma, a rare subtype that combines the characteristics of both Hodgkin and non-Hodgkin disease forms. Programmed cell death protein 1/programmed cell death ligand 1 (PD-L1/PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) modulate the immune system function. Immunological checkpoints can be stimulatory or inhibitory, and tumors can use these checkpoints to protect against immune system attacks. This is a case report of a difficult diagnosis and describes the most current treatment using checkpoint inhibitors, through the review of the clinical record of a patient diagnosed with gray area lymphoma in August 2019, using a descriptive and cross-sectional analysis of the clinical history and disease evolution. The case showed that pembrolizumab therapy is an effective treatment option for patients with rare gray zone lymphoma refractory to different lines of treatment. Both the diagnosis and treatment of gray area lymphoma remain a challenge for the medical and multiprofessional teams, and collaboration between them ensured effective treatment for the patient.