Dermoscopy of primary cutaneous B-cell lymphoma (PCBCL) Vincenzo Piccolo, MD,a Massimo Mascolo, MD, PhD,b Teresa Russo, MD,a Stefania Staibano, MD, PhD,b and Giuseppe Argenziano, MD, PhDa Naples, Italy Key words: dermoscopy; primary cutaneous B-cell lymphoma. CLINICAL PRESENTATION A 74-year-old woman presented with a patchy infiltrated oval erythematous lesion of her left breast that appeared 3 months before (Fig 1, A). A second patient, a 77-year-old man, sought consultation for the rapid appearance of multiple reddish, variably sized, firm nodules on his back (Fig 1, B). Fig 1. Clinical aspect, primary cutaneous B-cell lymphoma. A, Patchy infiltrated ovalar erythematous lesion of the left breast. B, Multiple reddish variably sized firm nodules on the back. DERMOSCOPIC APPEARANCE Dermoscopy in both patients showed a similar pattern, resulting from the combination of subtle arborizing vessels, salmon-colored background, and white areas/circles (Fig 2). From the Dermatology Unit, Second University of Naples,a and Department of Advanced Biomedical Sciences, Pathology Section, University of Naples Federico II.b Funding sources: None. Conflicts of interest: None declared. Reprint requests: Vincenzo Piccolo, Dermatology Unit, Second University of Naples, c/o II Policlinico, Edificio 9, Primo piano, Via Pansini 5 - 80131 Napoli, Italy. E-mail: piccolo.vincenzo@ gmail.com. J Am Acad Dermatol 2016;75:e137-9. 0190-9622/$36.00 ª 2016 by the American Academy of Dermatology, Inc. http://dx.doi.org/10.1016/j.jaad.2016.02.1217 e137 e138 Piccolo et al J AM ACAD DERMATOL OCTOBER 2016 Fig 2. Dermoscopy of primary cutaneous B-cell lymphoma. A combination of the same dermoscopic features including subtle arborizing vessels, salmon-colored background, and white areas/circles is seen in both patients. HISTOLOGIC DIAGNOSIS Histology showed a dense, diffuse, lymphoid infiltrate within the dermis and the subcutaneous fat consisting of small-cleaved lymphocytes and lymphoplasmacytic cells admixed with plasma cells, mainly located at the periphery of the infiltrate. The overlying epidermis was not involved. Neoplastic cells were CD201, CD79a1, and B-cell lymphoma-21 and CD5 , CD10 , and B-cell lymphoma-6 . The proliferative rate was low (Ki 67/MIB-1 of around 15%) (Fig 3). On the basis of these findings, a diagnosis of primary cutaneous B-cell lymphoma (PCBCL) (marginal zone) was made in both patients. Fig 3. Histopathology of primary cutaneous B-cell lymphoma (marginal zone). A, Dense diffuse infiltrate of small lymphocytes involving the dermis. There was no epidermal involvement. B, The infiltrate was composed of a predominance of small-cleaved lymphocytes. C and D, Neoplastic infiltrate. (A and B, Hematoxylin-eosin stain; C and D, CD20; original magnifications: A and C, 325; B and D, 3200.) J AM ACAD DERMATOL Piccolo et al e139 VOLUME 75, NUMBER 4 KEY MESSAGE PCBCLs are B-cell lymphomas that originate in the skin and usually present at the time of diagnosis without evidence of extracutaneous disease.1 Clinical presentation is extremely variable2 and histopathology is mandatory for definitive diagnosis. Recently, some of us have described a dermoscopic pattern for PCBCL, characterized by the association of white circles with a salmon-colored background/area, scales, and/or arborizing vessels.3 Because these features were also observed in the above-reported cases, these findings might be considered highly repetitive. To date, no precise correlation exists between each dermoscopic feature and its histopathologic correlation. However, the identification of such a combination of dermoscopic features may be very useful in clinical practice for the early recognition of PCBCL and prompt excision of this tumor. REFERENCES 1. Suarez AL, Pulitzer M, Horwitz S, et al. Primary cutaneous B-cell lymphomas: part I. Clinical features, diagnosis, and classification. J Am Acad Dermatol. 2013;69:329.e1-329.e13; quiz 341-342. 2. Mascolo M, Piccolo V, Iannuzzo G, et al. Primary cutaneous diffuse large B-cell lymphoma with cranial vault and dura mater involvement. J Eur Acad Dermatol Venereol. 2016;30:186-187. 3. Mascolo M, Piccolo V, Argenziano G, et al. Dermoscopy pattern, histopathology and immunophenotype of primary cutaneous B-cell lymphoma presenting as a solitary skin nodule. Dermatology. 2016;232:203-207.