Nodular B-Cell Cutaneous Lymphoid Infiltrate With Limited Tissue for Molecular Evaluation: A Case Highlighting Diagnostic Challenges and Management Variability

Cutaneous lymphoid infiltrates can mimic lymphoma and often present a diagnostic challenge. While gene rearrangement studies may help assess clonality, they are not always feasible in routine practice. We present a case of a nodular B-cell-predominant lymphoid infiltrate in the left proximal arm for which molecular testing could not be performed due to insufficient tissue. Histopathology and immunohistochemistry favored a reactive process, but diagnostic uncertainty remained. Management differed between providers. Dermatopathology recommended clinical monitoring, while the treating dermatologist referred the patient to hematology/oncology for further evaluation. The patient underwent a systemic workup but was ultimately lost to follow-up. This case highlights the limitations of tissue sampling, variability in management, and the importance of clinicopathologic correlation in cutaneous lymphoid infiltrates.