Primary Mediastinal B-Cell Lymphoma
Lessons From the Friday Unknowns
Histologic examination demonstrates sheets of neoplastic cells of intermediate-large size and admixed histiocytes are present, associated with sclerosis of tissue.
The neoplastic cells are positive for CD20, CD23 (variable), CD30 (weakly positive), CD45 (variable, weak), BCL6 and BCL2. Approximately 30–35% of neoplastic cells show positive immunostaining for MYC protein. Proliferation of neoplastic cells, as determined by the immunostain for Ki-67 antigen, is high, with percentage Ki-67 positive cells ranging from 70% to 85%. The neoplastic cells are non-immunoreactive for CD3, CD5, CD15, CD43, CD10, CD68 and cyclin D1. No meshworks of CD21 positive of follicular dendritic cells are are detected. In situ hybridization for EBV (EBER) is negative.
These findings in the setting of a 22 years old woman presenting with a mediastinal mass, are supportive of the diagnosis of primary mediastinal B-cell lymphoma (PMBL)
Digital to slides: https://bit.ly/3nyY0B1 | Slides labeled case 3
