B-Cell Lymphoma with a Folliuclar Immunophenotype Involving the Skin: Primary Cutaneous Follicle Center Lymphoma vs Large Follicular Lymphoma
Lessons From the Friday Unknowns
Histologic sections show fragments of skin and deep dermis involved by lymphoma. The lymphoma has a follicular pattern and is composed predominantly of cleaved and non-cleaved centroblasts, with scattered small centrocytes in the background. No epidermotropism seen.
The lymphoma cells are positive for CD10, CD20, BCL-6 and negative for CD3, CD30, BCL-2, kappa and lambda light chain. PAS special stain is negative for fungal organisms. The CD3 stain highlights scattered T-cells in the background. . Rare plasma cells are present and show a polytypic immunostaining pattern for kappa and lambda light chains.
The morphology and immunophenotype are consistent with B-cell lymphoma with a follicular immunophenotype. While primary cutaneous follicle center lymphoma is favored, the possibiliity of secondary cutaneous involvement by systemic follicular lymphoma cannot be excluded on histologic basis alone. If the current findings are related to systemic follicular lymphoma, the morphology could be classified as follicular grade 3A. Correlation with history and clinical findings is therefore suggested.
Link to digital slides: https://bit.ly/3WEWJIa | Case 3