Multiple lymphomatous polyposis of the gastrointestinal tract is a heterogenous group that includes mantle cell lymphoma and follicular lymphoma: Analysis of somatic mutation of immunoglobulin heavy chain gene variable region

Multiple lymphomatous polyposis (MLP) is characterized by multiple polyps i nvolving long segments of the gastrointestinal (GI) tract. MLP is thought t o represent mantle cell lymphoma (MCL) of the GI tract; however, some cases of follicular lymphoma (FL) of the GI tract are found with a multiple poly poid appearance. In the present study, to clarify the cellular origin of ML P, clonal immunoglobulin heavy chain (IgH) gene rearrangement of four cases with MLP was amplified by polymerase chain reaction (PCR) and analyzed for the presence of somatic mutation. The IgH variable (VH) region sequences o f three cases (CD5+ CD10- cyclin D1+) showed a little somatic mutation comp ared with the closest published germline, The other case (CD10+ CD5- cyclin D1-) was highly mutated and showed intraclonal heterogeneity (ongoing soma tic hypermutation). These data indicate that three of the cases with MLP ar e derived from pregerminal center B cells (mantle zone B cells) and one cas e with MLP from germinal center B cells. Our study suggests that MLP is a h eterogenous group that includes MCL and FL. HUM PATHOL 30:581-587. Copyrigh t (C) 1999 by W.B, Saunders Company.