Lipoma of the corpus callosum with atypical calcification

Lipomas of the corpus callosum are uncommon. They are usually associated with total or partial agenesis of the corpus callosum. The diagnosis can often be made from plain skull radiographs, which characteristically show a relative radiolucency in the position of the lipoma. Calcification is often associated with the lucency. This has a typical appearance, and standard text-books describe it as a thin, shelllike density in the capsule of the lipoma. In the frontal projection it converges inferiorly, like the letter U, and is symmetric around the mid-line. In the lateral projection a shell-like brim, partially surrounding the central lucency, is seen (Bergerhoff, 1963; Decker, 1960; du Boulay, 1965; Mullen and Hannan, 1950; Sutton, 1949; Taveras and Wood, 1964; Oftedal, 1959). None of these authors mentions solid calcifications, which must, therefore, occur extremely seldom. By perusal of the pertinent literature we have, however, found that Benjamin in 1858 described a lipoma with “a more 576 than walnut-sized centre” showing bone structure and Haversian canals. In Caffey's text-book there are pictures of a child, aged five months, with a probable lipoma of the corpus callosum and an irregular central calcification (Caffey, 1967).