Ataxia-telangiectasia mutated (ATM) gene mutation in a patient with primary cutaneous marginal zone lymphoma

Primary cutaneous marginal B-cell lymphoma (PCMZL), a type of extranodal marginal zone lymphoma (MZL) of mucosa-associated lymphoid tissue, is a common indolent non-Hodgkin lymphoma that typically presents with solitary or multifocal papules/plaques or tumors.1 Two types of PCMZL have been noted pathologically.1,2 The more common subtype is characterized by class-switched immunoglobulins without C-X-C chemokine receptor 3 expression and a small proportion of neoplastic B cells.1 A smaller subset shows a diffuse proliferation of neoplastic B cells that express immunoglobulin M (and often C-X-C chemokine receptor 3) and has a higher likelihood of extracutaneous disease manifestations.