The punch biopsy revealed dense lymphoid hyperplasia consistent with pseudolymphoma. The punch biopsy sample underwent notable immunohistochemical analysis to exclude lymphoma and was remarkable for a polyclonal set of B and T lymphocytes in a benign ratio, without epidermotropism.
Pseudolymphoma is an inflammatory response often induced by an arthropod bite, or occasionally, medication. Both T cell predominant and B cell predominant pseudolymphoma occur. Most present as a 5- to 30-mm pink papule on the head. They are rare below the waist and more common in young adults.
Basal cell carcinoma (BCC) is such a common diagnosis for a novel pink neoplasm on the face of an older adult that it is easy to forget the many other rare tumors and benign lesions (such as this one) present this way. An expanded differential diagnosis included cutaneous lymphoma, amelanotic melanoma, and granulomatous rosacea.
In this case, dermoscopy of the lesion (shown above) also was of limited help because BCC features of arborized vessels and shiny white lines were evident. There was a lack of more specific dermoscopic features such as spoke wheel–like structures, leaflike structures, or blue clods. This lack of more specific features might be the subtle clue to think beyond BCC when approaching the diagnosis. The history of rapid change was somewhat atypical for a BCC, which tends to grow more slowly. Patient history about the timing of facial lesions can be poor, but this patient’s history fit the ultimate diagnosis well.
This patient was treated with a superpotent topical steroid, clobetasol ointment 0.05% bid for 3 weeks. As a general rule, use of such a strong steroid is avoided on the face because of the risk of steroid atrophy, but in the case of pseudolymphoma or lymphoma, an exception is allowed. An alternative would be intralesional triamcinolone at a 5 to 10 mg/mL concentration. At follow-up 6 weeks later, the lesion was completely resolved.
Photos and text for Photo Rounds Friday courtesy of Jonathan Karnes, MD (copyright retained). Dr. Karnes is the medical director of MDFMR Dermatology Services, Augusta, ME.