BRIEF REPORT Composite Mantle Cell and Primary Cutaneous Anaplastic Large Cell Lymphoma: Case Report and Review of the Literature Charles Leduc, MD,* Ivan I. P. Blandino, MD, PhD,* Abdulmohsen Alhejaily, PhD,* Tara Baetz, MD,† David J. Good, MD,* Patricia L. Farmer, MD,* Jeremy A. Squire, PhD,* and David P. LeBrun, MD* Abstract: We describe the first reported occurrence of a composite cutaneous lymphoma involving a mantle cell lymphoma (MCL) and primary cutaneous anaplastic large cell lymphoma. The lesion occurred in a 76-year-old man with longstanding MCL who developed nodular skin lesions on his trunk and extremities. Biopsy revealed a CD30-positive lymphoma with pathological features characteristic of cutaneous anaplastic large cell lymphoma in the superficial dermis and a subjacent deposit of MCL in the deep dermis and subcutaneous adipose tissue. Immunophenotyping demonstrated T versus B lymphoid origin, respectively, for the 2 neoplasms, and fluorescence in situ hybridization demonstrated an 11;14 chromo- somal translocation exclusively in the MCL. These results argue that the lymphomas represented clonally distinct neoplasms. Our case illustrates the extreme diversity associated with the cutaneous manifestations of lymphoid neoplasia and in particular of composite lymphomas, which present diagnostic challenges for clinicians and pathologists alike. Key Words: composite lymphoma, mantle cell lymphoma, anaplas- tic large cell lymphoma, cutaneous lymphoma, primary cutaneous CD30 + lymphoproliferative disorders (Am J Dermatopathol 2015;37:232–236) INTRODUCTION The term “composite lymphoma” (CL) describes the simultaneous occurrence of 2 distinct and well-delineated varieties of lymphomas occurring at a single anatomic site. 1,2 The concept excludes cases that appear to arise through the progression and transformation of an indolent to a more aggressive lymphoma as occurs, for example, when chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/ SLL) progresses to diffuse large B-cell or Hodgkin lymphoma (HL). Although the literature describes a wide variety of combinations, most CLs involve the co-occurrence of a B lineage non-HL with HL. 3 CLs composed of lymphomas of different cell lineages are rare; when they occur, such cases most often combine diffuse large B-cell lymphoma and mycosis fun- goides (MF). 4 Here we report the first occurrence, to our knowl- edge, of a CL composed of mantle cell lymphoma (MCL) and primary cutaneous anaplastic large cell lymphoma (C-ALCL). CASE REPORT A 76-year-old man presented in November 2006 with shortness of breath and unintentional weight loss. He had mild cervical lymphadenopathy and normocytic anemia. Endoscopy and random duodenal biopsies revealed MCL involving the duodenal mucosa. Computed tomography revealed wall thickening of the small bowel and distal colon and extensive intra-abdominal and axillary lymphadenopathy. Six cycles of chemotherapy with ritux- imab, cyclophosphamide, doxorubicin, vincristine, and prednisone completed in June 2007 produced a good response with substantial reduction of lymphadenopathy. One year later, computed tomogra- phy demonstrated progression of abdominal lymphadenopathy, which responded well to chlorambucil treatment. However, approx- imately 2 months into treatment, a pruritic maculopapular rash appeared on the trunk and extremities. Repeat imaging studies indicated progressing intra-abdominal lymphadenopathy. The peripheral lymphocyte count and lactate dehydrogenase and liver transaminase levels were within normal limits. Third-line therapy with intravenous cyclophosphamide, vincristine, and prednisone produced no clinical response in either the lymphadenopathy or the rash. The rash remained relatively unchanged over several months and eventually progressed into several separate raised nodules, which became painful and ulcerated (Fig. 1). An excisional biopsy of one of the skin lesions was performed, and the patient was started on oral prednisone. The patient was then lost to follow-up before expiring in September 2010. Macroscopically, the skin ellipse exhibited a central ulcer and was markedly indurated. Histologic examination showed 2 distinct infiltrative cell populations within the dermis and subcutaneous tissue separated by a mildly fibrotic “demarcation zone” (Fig. 2). The deep- er component infiltrated the deeper portions of the reticular dermis and subcutaneous fat. These neoplastic cells were arranged in a vaguely nodular pattern and consisted of small lymphoid cells with somewhat irregular nuclear contours and dense chromatin (Fig. 3). Immunostains demonstrated expression by the lesional cells of CD45, CD20, CD43, CD5, PAX5, CD79a, and cyclin D1 but not CD2, CD3, CD4, CD10, CD23, CD15, CD30, T1A1, ALK, cytokeratin, or S100 protein. These findings identified the deeper component as cutaneous and subcutaneous involvement by MCL. In contrast, the more superficial process consisted of diffuse infiltration by mostly large, pleomorphic, prominently nucleolated From the *Department of Pathology and Molecular Medicine, Queen’s Uni- versity, Kingston, Ontario, Canada; and †Department of Oncology, Queens University and Cancer Centre of Southeastern Ontario, Kingston General Hospital, Kingston, Ontario, Canada. T. Baetz provides consultancy for Lundbeck, Roche, and Bristol Myers Squibb. The remaining authors declare no conflicts of interest. Reprints: Charles Leduc, MD, Department of Pathology and Molecular Medicine, Queen’s University, Richardson Laboratory, 88 Stuart Street, Kingston, Ontario, Canada K7L 3N6 (e-mail: 8cl58@queensu.ca). Copyright © 2014 Wolters Kluwer Health, Inc. 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