Anetoderma arising in cutaneous B-cell lymphoproliferative disease.

Anetoderma is circumscribed atrophy of the skin due to a localized deficiency in elastic tissue. It can follow inflammatory skin diseases of several types, and occasionally is present in the skin around neoplasms. There are a few reports of anetoderma in the lesional skin of cutaneous lymphoma. We report on two patients who presented with multiple lesions of anetoderma and who later proved to have low-grade cutaneous B-cell lymphomas. One patient (Patient 1) is a 39-year-old man and the other patient is a 26-year-old woman who is a renal transplant recipient (Patient 2). Some biopsy specimens from the anetodermic skin of Patient 1 appeared to show an urticarial reaction, although plasma cells were present. A large nodule showed lymphoid follicles surrounded by plasmacytoid lymphocytes, with loss of elastic tissue in the adjacent dermis. The plasmacytoid cells stained overwhelmingly for lambda light chain, and staining of the urticarial lesions from this patient also showed a marked majority of lambda positive cells. Immunoglobulin heavy chain gene (IgH) rearrangements showed a dominant clonal pattern in the nodular lesion. We classified the disease in Patient 1 as marginal zone lymphoma and the disease in Patient 2 as a post-transplant lymphoproliferative disorder. Because of the intimate association of anetoderma and cutaneous B-cell lymphoproliferative disorders in these two patients, it seems possible that anetoderma could result from either a local effect of the neoplastic cells or associated inflammatory cells, especially neutrophils as in Case 1. The infiltrates of Case 1 had many interstitial neutrophils and only a few clonal plasmacytoid lymphocytes, indicating that this presentation of B-cell lymphoma can be a diagnostic pitfall. Given these two cases and similar ones in the literature, biopsy of lesional skin in anetoderma should be performed to ensure that lymphomatous infiltrates are not present. Even if plasma cells are sparse, studies to detect clonality are appropriate. Cutaneous B-cell lymphoma can be added to the list of associations of elastolysis and cutaneous lymphoma, which includes granulomatous slack skin (T-cell lymphoma) and cutis laxa (myeloma).