Primary cutaneous lymphomas in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL): A series of 12 cases

Background Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is associated with an increased risk of a second malignancy. Methods We conducted a retrospective clinicopathologic review of 12 patients with CLL/SLL who developed a second lymphoma in the skin. Demographic data, clinical information, and histopathology from 31 biopsies were recorded. Cases of secondary cutaneous involvement by CLL/SLL (leukemia cutis) and non‐primary cutaneous lymphomas were excluded. Results A wide variety of primary cutaneous lymphomas was identified, including classic mycosis fungoides (3), cutaneous marginal zone lymphoma (2), primary cutaneous peripheral T‐cell lymphoma unspecified (2), folliculotropic mycosis fungoides (1), Sézary syndrome (1), cutaneous gamma‐delta T‐cell lymphoma (1), cutaneous CD8+ aggressive epidermotropic cytotoxic T‐cell lymphoma (1), and cutaneous anaplastic large cell lymphoma (1). A male predominance was observed, and the average age was 74.1 years. In all patients, CLL/SLL predated the development of the second lymphoma, which was aggressive in the majority of cases (58%). Aggressive cytotoxic T‐cell lymphomas, generally rare neoplasms, were relatively common (30%). Conclusions CLL/SLL patients may develop a second lymphoma in the skin, which may be aggressive. Atypical cutaneous lymphoid infiltrates in this patient population should not be assumed to represent secondary CLL/SLL involvement and require thorough immunohistochemical analysis.