Primary cutaneous extranodal marginal zone B-cell lymphoma of the eyelid skin: Diagnostic clues and distinction from other ocular adnexal diseases.

A 60-year-old man developed a rubbery thickening and erythema of his left lateral upper and lower eyelids and lateral canthus over several months. He was treated for an extended period of time for blepharitis and chalazia. Incisional biopsy eventually disclosed microscopically a hypercellular lymphoid population sparing the epidermis that surrounded adnexal structures and infiltrated between orbicularis muscle fibers. Immunohistochemically, the lesion was found to be composed of neoplastic, kappa-restricted B cells with an equal number of reactive T cells and small reactive follicles. The diagnosis was a primary cutaneous extranodal marginal zone B-cell lymphoma of the eyelid skin (EMZL). We review the distinguishing clinical, histopathologic, and immunohistochemical features of cutaneous EMZL and contrast those with EMZL of other ocular adnexal sites. Also offered is a differential diagnosis of cutaneous lymphomas of the eyelid skin, which are predominately T-cell lesions.