PMLBCL : Differential Diagnosis

Comments:
Differential Diagnosis of Primary Mediastinal Large B-cell Lymphoma (PMLBCL) (continued from previous slide): The list includes - classic Hodgkin lymphoma (cHL), diffuse large B-cell lymphoma, NOS (DLBCL-NOS), anaplastic large cell lymphoma (ALCL), mediastinal seminoma, thymic carcinoma, and thymic carcinoid.

Features favoring Anaplastic Large Cell Lymphoma: hallmark cells - large anaplastic cells with eccentric horseshoe- or kidney-shaped nuclei and abundant clear, eosinophilic or basophilic cytoplasm, pan B-cell -ve, pan T-cell +/-, ALK+/-, CD30+, EMA+/-, cytotoxic markers +/-

Features favoring PMLBCL: Presence of sclerosis, Pan B-cell+, Pan T-cell-ve, EMA-ve

Features favoring Mediastinal Seminoma: male patient, round nuclei, lymphocytes in fibrous septa separating tumor cells, CD45-, CD117+, PLAP+, OCT3/4+

Features favoring Thymic Carcinoma: cohesive sheets, cytokeratin+, squamoid features, Pan B-cell-, CD45-

Features favoring Thymic Carcinoid: Organoid pattern, rich vasculature, rosettes, cytokeratin+, neuroendocrine markers+, CD45-, Pan B-cell-