Malignant histiocytosis of the intestine. Its relationship to malabsorption and ulcerative jejunitis.

The clinical and histopathologic features in seven patients with intestinal lymphoma are reported. Three of these presented with ulcerative jejunitis and four with overt lymphomas. A short history of abdominal pain with weight loss followed by intestinal obstruction, hemorrhage, or perforation characterized all the patients except one in whom a nine year history of malabsorption preceded the acute phase of the disease. Malabsorption was demonstrated in four of the patients, and all showed villous atrophy with crypt hyperplasia of the jejunum remote from areas of ulceration or frank lymphoma. The malignant lymphoma cells showed varying degrees of pleomorphism and exhibited phagocytosis of platelets, red cells, and cell debris. The accompanying infiltrate of inflammatory cells often overshadowed the neoplastic histiocytes, and in those cases showing little pleomorphism these cells could be easily overlooked. In the intestine the tumor cells were usually present as a diffuse infiltrate in the lamina propria or within the bases of ulcers and in five of seven cases did not give rise to macroscopic tumor masses. In all patients dissemination of tumor cells to the lymph nodes, liver, spleen, and bone marrow was evident, the infiltrate in all these organs resembling that seen in malignant histiocytosis. The morphology of the tumor cells, their phagocytic nature, the diffuse character of the tumor infiltrate, and the pattern of dissemination suggest that this lesion should be designated malignant histiocytosis of the intestine rather than histiocytic lymphoma (reticulum cell sarcoma). It is suggested that the tumor may arise from cells of monocyte-histiocyte lineage normally present in the lamina propria of the gut and that a prolonged cryptic phase accompanied, and often overshadowed, by an inflammatory reaction may give rise to malabsorption and ulcerative jejunitis before overt lymphoma is manifest.