Subepidermal calcified nodule

13 year-old female on the left upper eyelid

At low power (40x), there is a somewhat exophytic papule with prominent epidermal hyperplasia and hyperkeratosis. There are dilated follicle-like structures filled with compact keratotic material. Clearly evident even at this low magnification is an altered dermis filled with basophilic material.

At higher power (100x), it becomes more apparent that the dermis is filled with deposits of crystalline material that extend right up to the dermoepidermal junction.

The deposits are polygonal in shape with blue to purple hues. Many seem to be fractured from adjacent deposits and even rimmed by a fibrous border. Dilated vascular structures are also observed.

The follicle-like structure is lined by pale, hyperplastic epithelium, although keratinocytes do not demonstrate cytologic atypia. Pale basophilic polygonal deposits are surrounded by neutrophils.

The deposits extend up through the follicle to the surface and are present in the stratum corneum.

Subepidermal calcified nodule is a condition often seen in children characterized by large deposits of calcified material