[Pilomatrixoma. Pseudoampullar form and other clinical varieties].

Pilomatrixoma presents clinical variants, ulcerated and tumorous, angioid and one very special type characterized because the skin covering the tumor is very thin (anetodermic), pink and folded, simulating an involuting blister. The authors that observed six cases of this variant, considered that for this reason they can name it the "pseudoblistering form of pilomatrixoma". The histopathology that appears in this pseudoblistering variant is characteristic because the collagen existing between the tumor and the epidermis is atrophied and its fibers are separated by the intense edema.