February 2003

2.

3.

4.

Histopathology:

There is a normal epidermis overlying a nodular infiltrate with large mononuclear cells (centroblasts and immunoblasts). Numerous mitotic figures and apoptotic cells are present (Figures 2 and 3). Immunohistochemical stains results include: Myeloperoxidase -, lysozyme -CD20 + (Figure 4), CD79a +, CD2 -, CD3 -, CD5RO ­

Diagnosis:

Primary cutaneous B-cell lymphoma, large cell type

Discussion:

Non-Hodgkin's lymphomas arise from the lymphoreticular system. Extranodal involvement occurs in 25% of NHL, with the skin being the second most common site of involvement. The annual incidence of cutaneous lymphomas is 0.5-1 per 100,000 people, of which B-cell lymphomas comprise 20-25%. Primary cutaneous B-cell lymphoma (PCBCL) is a Non-Hodgkin's lymphoma that is subdivided into follicle center cell large B-cell lymphoma (>40%), large B-cell lymphoma of the leg (5-10%), and a provisional category. The etiology of PCBCL is unclear but may be related to infectious, chromosomal, or immunologic factors. Diagnosis is based on clinical, histopathologic, and immunophenotypic evaluation. Treatment includes radiation therapy, polychemotherapy, surgical excision, or a combination of these modalities. Newer therapies, including interferon alfa and monoclonal antibodies, are currently being investigated. Recurrence rates are significant, as high as 68%.

Follicle center large B-cell lymphoma affects middle aged men and women equally. It typically presents as red papules on the head, neck, and trunk and has an excellent prognosis with a 5-year survival rate of >90% with treatment.

Large B-cell lymphoma of the leg occurs predominantly in women over 70 years of age. It presents as red to bluish papules and nodules on one or both lower extremities. It behaves more aggressively, with a 5-year survival rate of < 50%.

References:

1. Fitzpatrick's Dermatology in General Medicine, 5th ed. (Freedberg IM, Eisen AZ, Wolff K, Austen KF, Goldsmith LA, Katz SI eds.). New York: McGraw-Hill, 1999. pp 1250-56.

2. Burg G, Kaudewitz P, Kelpzig K, Przybilla B, and Braun-Falco O. Cutaneous B-cell lymphoma. Dermatol Clin, 3:689-703, 1985.

3. Pandolfino TL, Siegel RS, Kuzel TM, Rosen ST, and Guitart J. Primary cutaneous B-cell lymphoma: Review and current concepts. J Clin Oncol, 18:2152-68, 2000.

4. Wechsler J and Bagot M. Primary cutaneous large B-cell lymphomas. Semin Cutan Med and Surg 19:130-2, 2000.

My thanks to Drs.Helen Kim-James,Yadira Rothschild and Susan Mallory for their assistance inthe preparation of tis case.