Anaplastic large cell Ki-1 lymphoma of the stomach with villopodial projections: an immunocytochemical and ultrastructural study and review of the literature.

The report describes a case of anaplastic large cell Ki-1 lymphoma of the stomach with a rapidly fatal course observed in a 28-year-old woman. By electron microscopy the neoplastic cells presented long projections of the cytoplasmic membrane arranged uniformly along all the cell circumference. The morphology and distribution of these projections were characteristic, and the term villopodial is proposed for them. A review of the literature revealed 18 cases of lymphoma and 7 cases of nonlymphoid neoplasms composed of cells with projections similar to those observed in the present case. It is suggested that such tumors be denominated villopodial lymphomas and villopodial tumors. The present case is the first anaplastic large cell Ki-1 lymphoma with villopodial projections reported in the literature.