Mucosal pseudolipomatosis of the colon.

Twenty-four cases of a lesion characterized by unlined spaces in the colorectal lamina propria are presented. While lesions such as this have been reported previously as "lipomatosis" of the colon, histochemical and ultrastructural examination reveals that they are not, in fact, composed of adipocytes. It appears that they may be composed of gas trapped in the lamina propria. Because of their gross and microscopical similarity to fat, however, the term "pseudolipomatosis" is proposed.