Collagenoma or collagen nevus of the connective tissue is a hamartomatous malformation of the dermis, characterized by a proliferation of normal collagen tissue. This may be congenital or acquired, solitary or multiple, hereditary or sporadic. The solitary type are sporadic, not associated with any disease, and may appear on any part of the body. Histology studies show an increase of collagen fibers in the dermis and a variable decrease in elastic fibers. We discuss the case of a child with a solitary giant cerebriform collagenoma on the lumbar region of her back.