Mediastinal gray zone lymphoma (MGZL) is a rare B cell lymphoma originated from the thymic niche. An incostistency between morphological and immunohistochemical findings is the hallmark of the disease . Both 2022 WHO classification and International Consensus Classification renamed the disease as Mediastinal Gray Zone Lymphoma which excluded non-mediastinal forms. Due to rarity and clinical presentation of mediastinal bulky disease prospective trials for the management of MGZL is limited.

Case report: Twenty-nine years old female patient admitted to hospital with dyspnea and night sweats. Basal scans showed an anterior mediastinal mass lesion of 5 × 5 × 6 cm diameter. Tru-cut biopsy of the lesion showed MGZL, cHL -like subtype with immunohistochemically CD 30, CD15, PAX-5 positivity and strong CD20 positive giant cell containing atypical lymphoproliferative mass in a sclerotic background . Background consisted of numerous mature lymphocytes, rare eosinophils, histiocytes and plasma ce

PET-CT showed anterior mediastinal mass of 8,7 X 6,2 cm standing just behind pericardium with a SUVmax of 28,3 . Along with mediastinal mass right prevascular,preparacardiac and anterior diaphragmatic lympadenopaties of maximum length of 2,5 cm and with a SUVmax ranging between 7,04 and 24,7 were detected. Basal tests showed iron deficiency anemia of hemoglobin 9,8 g/dl and erythrocyte sedimentation rate of 29 mm/hour. LDH was 645 IU/l. Pretherapy echocardiograpy showed pericardial effusion

Background consisted of numerous mature lymphocytes, rare eosinophils, histiocytes and plasma cells . PET-CT showed anterior mediastinal mass of 8,7 X 6,2 cm standing just behind pericardium with a SUVmax of 28,3 . Along with mediastinal mass right prevascular,preparacardiac and anterior diaphragmatic lympadenopaties of maximum length of 2,5 cm and with a SUVmax ranging between 7,04 and 24,7 were detected. Basal tests showed iron deficiency anemia of hemoglobin 9,8 g/dl .

Targeted therapies especially PD-1 blockage and anti-CD30 therapies are increasingly filling the gap for the management of GZL s as well as cHL and PMBCL. Brentuximab vedotin is a promising agent for the management of GZLs both in the first line and in the relapsed/ refractory setting.