The case of a 58-year-old man with chronic lymphocytic leukemia (B-cel
l type) who later developed an intussuception of the small intestine d
ue to a tumor is described. The histopathological findings of the remo
ved tumor were compatible with those of diffuse small lymphocytic lymp
homa (B-cell type). The residual tumor became smaller with CHOP therap
y. It is considered that CLL cell infiltration into the small intestin
e resulted in intussuception. Since many tumors and lymphomas can form
polypoid lesions causing an intussuception. This is a possible compli
cation of CLL and it could occur even when the WBC count is well contr
olled.