Cutaneous marginal zone lymphoma (MZL) may be a primary cutaneous condition or the result of secondary involvement from noncutaneous MZL. Distinguishing primary cutaneous MZL (PCMZL) from secondary cutaneous MZL (SCMZL) is of utmost importance for prognostic and therapeutic approach.

We describe the clinical and histologic features of 4 cases of SCMZL (3 cases of nodal MZL and one case of orbital extranodal MZL), compare them with a cohort of 30 cases of PCMZL, and describe distinctive features of SCMZL.

Thirty cases of PCMZL and 4 cases of non-PCMZL with secondary skin involvement were identified in our cutaneous lymphoma and dermatopathology databases. The medical records were reviewed regarding clinical, histologic, laboratory, and radiologic findings; disease course; response to treatment; and follow-up. All cases were reviewed by 3 dermatopathologists.

The histopathological and immunohistochemical features of SCMZL were indistinguishable from our cases with PCMZL. However, the clinical presentation in SCMZL appeared to be distinct. We observed these lesions in an older patient population and in 3 of 4 cases the lesions predominantly involved the head/neck area.

As PCMZL and SCMZLs are exceedingly rare, only 34 patients were identified in this single-institution study.

The histologic and immunophenotypic changes in skin lesions from SCMZL may be indistinguishable from those in PCMZL. However, there may be some differences in the typical clinical presentation. PCMZL may be seen in younger patients and favors the trunk and extremities whereas MZL secondarily involving the skin favors the head/neck regions and is limited to older patients. Because there may be considerable overlap in the clinical presentations for patients with primary and secondary cutaneous disease, it is not unreasonable to perform a systemic evaluation for all patients.