Primary cutaneous B-cell lymphoma in a 74-year-old Caucasian male.

Primary cutaneous B-cell lymphoma is an uncommon neoplasm with classification schemes that may be confusing, but with clinical presentations that are relatively consistent. Clinical exam and history can raise the index of suspicion for this condition, although the diagnosis is confirmed only by pathological evaluation. We report such a scenario in the case of a 74-year old male with a slowly expanding oval plaque on his right upper arm.