LAUSR

Primary cutaneous lymphomas (PCLs) are classified as a type of non-Hodgkin’s lymphoma (NHL). They are the second most common group of extranodal NHLs after the gastrointestinal lymphomas, with a global an­ nual incidence of approximately 1/100,000 in Western countries (1). PCLs include cutaneous T-cell lymphomas (CTCLs), which constitute approximately 75–80% of all PCLs, and cutaneous B-cell lymphomas (CBCLs), which represent approximately 20–25% of all PCLs (2). Mycosis fungoides (MF) is the most common type of CTCL, whereas primary cutaneous CD30+ lympho­ proliferative disorders (CD30+PCLPDs) are the second most common type. Within the group of CD30+PCLPDs, lymphomatoid papulosis (LyP) and cutaneous anaplastic large cell lymphomas (C-ALCL) can be distinguished (2). Both LyP and C-ALCL have an excellent prognosis (3). LyP is an indolent lymphoproliferative disorder clinically characterized by recurrent papulonodular lesions, which undergo spontaneous regression (4). Histologically, 6 types (A–F) of LyP with different histopathological and clinical features have been described (5–8). C-ALCL generally presents clinically with solitary or localized ulcerating tumours or nodules, although multifocal distribution of lesions are described in 20% of cases (9). Histologically C-ALCL are characterized by a diffuse non-epidermotropic infiltrate with more than 75% of cells positive for CD30 (10). Treatment of LyP usually involves low-dose methotrexate (MTX) and ultraviolet (UV) phototherapy, whereas localized radiotherapy and surgical excision are commonly used for treatment of CALCL (3). Recently, a variant of C-ALCL, characterized by an angiocentric/angiodestructive pattern and cytotoxic phenotype, has been described (11).