Follicular lymphoma with prominent Dutcher body formation: a pathologic study of 3 cases in comparison with nodal or splenic lymphoplasmacytic lymphoma and marginal zone lymphoma.

Dutcher bodies have been described in lymphoid neoplasms with plasmacytic differentiation, including plasma cell myeloma, lymphoplasmacytic lymphoma, and marginal zone lymphoma. We report a pathologic study of 3 cases of follicular lymphoma with extensive Dutcher body formation in comparison with lymphoplasmacytic lymphoma and marginal zone lymphoma. Of 3 cases, 1 showed a follicular growth pattern, whereas the other 2 cases demonstrated only a vague nodular appearance highlighted by immunohistochemical analysis. Cells containing Dutcher bodies were counted at 25, 90, or 110 per high-power field in each case, respectively. In 2 cases, cells with Dutcher bodies were clustered in an intrafollicular distribution, a possible histopathologic clue for follicular lymphoma. Immunoglobulin M κ was identified as the component of Dutcher bodies in all 3 cases, implying a possible molecular basis for the formation of Dutcher bodies in B-cell lymphomas. All 3 cases had cytogenetic changes supporting the diagnosis of follicular lymphoma, including dual rearrangement of BCL2 and BCL6, rearrangement of BCL2 with trisomy 3 (BCL6), and isolated BCL6 rearrangement. We emphasize immunohistochemical analyses with anti-κ/λ and anti-immunoglobulin heavy-chain isotypes to characterize Dutcher bodies and document clonality in addition to the routine lymphoma workup and indicated cytogenetic studies in B-cell lymphomas with prominent Dutcher bodies.