Author: Assoc Prof Patrick Emanuel, Dermatopathologist, Auckland, New Zealand, 2013.
Dermoid cysts are derived from the ectoderm and involve embryologic closure lines.
Histology of dermoid cyst
Sections show a subcutaneous cyst which is often received “shelled out” (figure 1).
The lining is typically a keratinizing squamousepithelium (figures 2, 3). The hallmark of these cysts is the presence of pilosebaceous structures in the cyst wall (figures 2, 3). Hair shafts are often found within the cyst (figure 3, arrow).
Less common findings include a columnar or mucous secreting epithelium, smooth muscle in the cyst wall, and surrounding eccrine glands.
Steatocystoma – Steatocystoma shows sebaceous glands connecting to the cyst lining but the pilar structures are not seen. The lining lacks a granular layer and has a characteristic corrugated keratin layer.
Weedon’s Skin Pathology (Third edition, 2010). David Weedon