Unusual B-Cell Lymphoproliferative Disorders Co-Occurring With Nonmelanoma Skin Cancer: Report of Three Cases.

The coexistence of nonmelanoma skin cancers and B-cell lymphoproliferative disorders represents a significant diagnostic challenge. Although peritumoral lymphoid infiltrates are frequently interpreted as reactive, they may occasionally correspond to underlying or previously unrecognized lymphoproliferative disorders, with relevant clinical implications. We report three diagnostically challenging cases of epithelial skin cancers associated with unusual B-cell lymphoproliferative disorders, including composite lymphomas and previously unreported associations. These cases highlight the broad spectrum of B-cell lymphoproliferative conditions that may coexist with epithelial skin malignancies and underscore the importance of meticulous morphological assessment, comprehensive immunophenotypic characterization, and careful clinicopathological correlation. Awareness of this potential association is crucial to avoid misclassification of neoplastic lymphoid infiltrates as reactive processes and to ensure appropriate hematological work-up and optimal patient management.