Antisolarium egenum is a small sea snail, a marine gastropod mollusc in the family Trochidae, the top shells.

The thin, minute shell has a low ovate-conic shape and is amply umbilicated.

Each whorl is encircled by four sharply-compressed well-elevated ribs, the two uppermost of which are beaded.

The interspaces are concave, smooth, with a single groove near the margin of the umbilicus.

The aperture is nearly circular, slightly encroached upon by the inflection of the columella.