Primary Cutaneous B-cell Lymphoma Presenting in an Adolescent Male: A Case Report

Primary cutaneous marginal zone lymphoma (PCMZL) is a low-grade B-cell lymphoma of the skin that arises from mucosa-associated lymphoid tissue (MALT) and is characterized by a heterogeneous infiltrate of marginal zone B cells, small lymphocytes, and plasma cells. PCMZL is a subtype of primary cutaneous B-cell lymphoma (pcBCL). Pediatric PCMZL is exceedingly rare, with only a limited number of cases reported, and it is rarely encountered in clinical practice. Clinically, it typically presents in children or adolescents as solitary or multifocal skin lesions, most commonly on the limbs and trunk, with occasional involvement of the face. Histopathologically, the disease is marked by a mixed inflammatory infiltrate involving B cells and reactive immune cells. In children, PCMZL usually follows a slow-growing course, and treatment often involves localized or conservative therapies, with an overall excellent prognosis. Here, we report the case of a 16-year-old male patient presenting with a solitary skin nodule on the upper left arm.