Extranodal marginal zone lymphoma from ocular adnexae with subcutaneous involvement.

Extranodal marginal zone lymphoma (MZL) of mucosa-associated lymphoid tissue usually originates from cutaneous or mucosal surfaces. A rare site of involvement is the subcutaneous tissue of any location. Here, we describe a 58-year-old man who presented with bilateral extranodal MZL of mucosa-associated lymphoid tissue from ocular adnexae that involved subcutaneous tissue and subsequently extended to multiple anatomical locations in the head and neck, upper back, and arm. The neoplastic cells expressed B-cell markers, and the plasma cells expressed IgG4. The unusual pattern of infiltration of this extranodal MZL and the possible significance of IgG4 expression in this case are discussed.