Primary lymphomas of the gastrointestinal tract. I. Plasma cell tumours.

The histology of 125 cases of primary gastrointestinal lymphomas arising in the stomach and small and large intestine has been reviewed. The material was gathered from the Bland-Sutton Institute of Pathology at the Middlesex Hospital and from the Westminster Hospital. Of the initial total of 143 cases diagnosed, 18 were rejected. Of the acceptable 125 cases, 51 lymphomas were arising in stomach, 53 in the small intestine and 21 in the large intestine including rectum. Excluding the four children in the series, ages ranged from 18 to 82 and were fairly evenly distributed across the decades. There was no significant sex difference in the Middlesex Hospital cases but in the Westminster Hospital series the male to female ratio was approximately 2.6 to 1. One significant finding to emerge from this histological survey, and which forms the basis of this communication, is the proportion of lymphomas considered to be predominantly of plasma cell type. These plasma cell tumours, or extramedullary plasmacytomas, accounted for 49 out of the 125 cases (39%) of gastrointestinal lymphomas. They were less common in stomach and most common in the intestine, the majority occurring in the ileocaecal region. Conversely, Hodgkin's disease, in contrast to some series, was not encountered. Of the non-Hodgkin's lymphomas, grade I tumours were uncommon and true histiocytic lymphomas were distinctly rare. The high incidence of plasma cell tumours were uncommon and true histiocytic lymphomas were distinctly rare. The high incidence of plasma cell tumours in our series is in keeping with the morphological findings of a previous study carried out in patients with alpha-chain disease and in a small series of primary gastrointestinal lymphomas.