Symptomatic ovarian involvement as the initial presentation of primary mediastinal large b-cell lymphoma

•PMLBCL is an uncommon thymic B-cell neoplasm accounting for about 2.5% of NHLs.•Patients present with bulky mediastinal lymphadenopathy,causing dyspnea and dry cough.•Extrathoracic distal extranodal sites is a rare event at disease presentation.•This is a unique case of a young female patient with symptomatic, bulky ovarian tumor.•PMLBCL was finally diagnosed with a clinically silent bulky mediastinal mass.