Grey zone lymphoma - diagnostic and therapeutic challenge

Introduction. ?Grey zone Lymphoma?? is associated with various entities. The last published classification of lymphoproliferative neoplasms includes mediastinal grey zone lymphoma. Precise diagnostic criteria are insufficient and establishing a diagnosis is as complex as deciding on treatment options. In this article pathologist and hematologist discuss issues on this topic through case presentation and literature review. Clinical characteristics. It presents in the younger population usually with a mediastinal mass, sometimes large, with compressive symptoms. Pathologic characteristics. Some cases can?t be classified neither as Hodgkin nor Primary mediastinal B-cell lymphoma. Morphology resembles Hodgkin, but with a positive immunophenotype for primary mediastinal or diffuse large B-cell lymphoma, and vice versa. Case report. We presented a case of a 33-year-old male with cervical lymphadenomegaly, B symptoms and clinical deterioration during the diagnostic period. After the first biopsy, differential diagnosis was Epstein-Barr virus-associated lymphoproliferative disorder or classical Hodgkin lymphoma. The second biopsy confirms Epstein-Barr virus-positive diffuse large B-cell lymphoma. The World Health Organization Classification of lymphoproliferative neoplasms - clinical perspective. The term ?grey zone lymphoma? is associated with overlapping diagnosis or uncertainty in diagnosis in more clinical settings than the ones provided in the 5th World Health Organization Classification. Discussion. For now, chemotherapeutic regimen (rituximab-cyclophos phamide, doxorubicin, vincristine, prednisone) stays the standard first line therapy for diffuse large B-cell lymphoma regardless of the Epstein- Barr virus status. Mediastinal grey zone lymphoma treatment varies: chemotherapeutic regimen (rituximab-cyclophos phamide, doxorubicin, vincristine, prednisone) was linked with better outcomes than chemotherapeutic regimen (adriablastin, bleomycin, vinblastine, dacarbazine) +/-R, but for some patients chemotherapeutic regimen (dose adjusted-etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin) might be beneficial. Conclusion. Grey zone lymphoma is a rare hematologic malignancy that needs extensive sampling for correct diagnosis and is still subject to inter-observer variability.