Diffuse peritoneal seeding in immunoblastic lymphosarcoma.

The authors report a case of immunoblastic lymphosarcoma of B cells with an unusual presentation. Laparotomy on a 67-year-old women with an abdominal mass revealed extensive peritoneal seeding resembling carcinomatosis. At autopsy, immunoblastic lymphosarcoma, probably originating in the bowel wall, was found. It was studied by light, immunofluorescent and electron microscopy. Histologic examination showed monomorphic proliferation of malignant immunoblasts with plasmacytoid features. Immunofluorescent microscopy was positive for intracytoplasmic IgG, IgA, kappa and lambda light chains. The presence of diffuse peritoneal seeding in patients with malignant lymphomas is not well documented. The clinical and pathologic features of this entity and its relation to Mediterranean lymphoma are discussed.