The purpose of this exhibit is to display the pathologic events in acne vulgaris. Because it attacks the face, histopathologic study heretofore has been limited.
The lesions of acne occur in special follicles, the sebaceous follicles (Fig. 1), which are found in great abundance on the cheek and forehead. These follicles also occur on the chin, in the beard, and to a less extent, on the back and chest. They are characterized by (1) widely dilated follicular canals filled with keratin, lipids, and organisms; (2) massive multilobular sebaceous acini lying deep in the dermis; (3) small inconspicuous vellus hairs which cannot keep the follicle cleared out.
Two types of comedones develop in sebaceous follicles: 1. The clinical "black-head" (Fig. 2) is an open comedo composed of an epithelium-lined sac filled with horny lamellated material (Fig. 3). The mouth is widely dilated; the contents can escape to the surface, and it