Primary Cutaneous Mantle Cell Lymphoma: A Case Report

Primary cutaneous mantle cell lymphoma (MCL) is a rare cutaneous proliferation of naive pregerminal CD-5 positive B cells in the skin with no extracutaneous involvement. Overexpression of cyclin D1 is pathognomonic of this condition, and surgery and radiation therapy are the most common therapeutic options. In this case, we describe the clinical, histopathological, immunohistochemical, and molecular characteristics of a new case of primary cutaneous MCL. 1. Introduction Mantle cell lymphoma (MCL) is a clinical entity characterized by the proliferation of CD5-positive antigen-na？ve pregerminal centre B cells within the mantle zone that surrounds normal germinal centre follicles [1]. This lymphoma is associated with the chromosomal translocation t(11, 14)(q13; q32) responsible for cyclin D1 overexpression [2–4]. Primary MCL is not included in the World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) classification for cutaneous lymphomas [5]. 2. Clinical Case A 72-year-old woman was seen in our clinic because of a solitary, slowly progressive erythematous nodule on the back of six months of duration. Her general health was otherwise unremarkable (Figure 1). Figure 1: See the solitary and erythematous nodule of 1？cm in diameter on the patient’s back. Punch biopsy of the lesion was performed. Histopathological examination showed a diffuse lymphoid infiltrate of intermediate to large cells that involved the dermis (Figure 2). Figure 2: Histopathology: lymphoid dermal proliferation infiltrating epidermis (arrow) hematoxylin-eosin (10x). Immunohistochemistry showed the following phenotypical characteristics: CD3+, CD5+, CD20+, CD43+, CD45+, CD23？, BCL2+, and cyclin D1+ (Figures 3 and 4). On the basis of the histological and immunohistochemical data, a diagnosis of MCL was made. Figure 3: Positive cyclin D1 nuclear immunoreactivity in lymphoma cells (40x). Figure 4: Positive CD5 immunoreactivity in cytoplasm of lymphoma cells (40x). Computed tomography scans of the head, neck, thorax, abdomen, and pelvis showed no pathological findings. Total body positron emission tomography (PET) did not reveal any systemic involvement. Clinical staging showed no evidence of bone marrow or peripheral blood involvement. Histopathological flow cytometry and cytogenetic of the bone marrow revealed no evidence of MCL with karyotype 46 XX. A diagnosis of primary cutaneous MCL was therefore made and the nodule was operated. After three months, a new lesion of similar characteristics was seen on the back, 15？cm away from the first. The new