Malignant lymphoma of the rectum

Eleven patients with primary lymphoma of the rectum were reviewed on a mainly histological basis, especially in association with reactive lymphoid hyperplasia (RLH). They included three males and eight females with an age range of 21-71 (median 59) years. Common symptoms were anal bleeding, melena, difficulty with defecation and constipation. A physical examination echogram and computed tomographic scans showed the tumor to be restricted to the rectum. The tumors were classified microscopically as six intermediate lymphocytic lymphomas (ILL) and five others. Histologic findings compatible with RLH were found in all five ILL cases and three of the others. Immunohistochemistry on paraffin-embedded sections revealed eight cases to be of B-cell type and one with a pleomorphic histology, to be of T-cell type; one case did not react with any of the antibodies tested, but were regarded as being of B-cell type purely on morphological grounds. A gene rearrangement study carried out in one ILL case showed a monoclonal rearrangement of the Jh chain. The findings showed rectal lymphoma to be characterized by a high frequency of ILL cases and an association with RLH. These are also common findings among patients with thyroid, salivary and gastric lymphoma, suggesting a common etiologic role in these diseases of long-standing inflammation.