Leontiasis Ossea

LEONTIASIS OSSEA (from Latin leo - lion), "bony lion-ness" (syn.: hyperostosis cranii, cranio-sclerosis), a name proposed by Virchow to denote a rare disease consisting of more or less uniform hyperostosis, i.e., the overgrowth and hardening of the bone substance of the facial and cranial bones. In view of the fact that the altered facial bones begin to protrude in the form of massive bumps, the face acquires a certain resemblance to the muzzle of a lion (see figure). It should be noted that the name L. o. must not be confused with the term "facies leontina" (lion face), which is applied to a change in facial appearance similar in external signs during leprosy, leukemia (see), and other diseases, which, however, are based not on bone lesions, but on a specific change in the skin.

L. o. usually begins in youth, and in some cases, the onset of the disease could be linked to trauma to the face or skull, erysipelas of the scalp, or purulent inflammation of the lacrimal sac. Of the facial bones, the zygomatic bones and zygomatic arches, the edges of the eye sockets, and the lower jaw are most intensely affected. In these bones, the bone substance increases in mass, overgrows, the bone tissue acquires a compact character, and the bone marrow becomes fibrous; flat growths of bone substance appear on the surface of the bones, initially finely porous, later becoming compact, very dense, resembling ivory. The bones of the cranial vault sometimes thicken up to 3-4 cm, the diploe disappears, and the bones become heavy and marble-dense. The weight of the entire skull in a dried state reaches 3 kg (normal 1 kg). The above-mentioned change in the bones results in a decrease in the volume of the cranial cavity, a narrowing of various cavities and openings on the face, as well as slits and openings through which blood vessels and nerves pass. This is the cause of headaches, neuralgias, weakening of vision, hearing, and smell, paralysis, and convulsions, from which patients with L. o. often suffer. - The pathogenesis of L. o. after the works of Recklinghausen and M. B. Schmidt is considered clarified in the sense that L. o. is identical to the hyperostotic form of fibrous osteitis, i.e., deforming osteitis (Paget), representing this disease localized to the bones of the skull and face and already having ended in osteosclerosis (see Fibrous osteitis). It is interesting that in L. o., as in fibrous osteitis, hypertrophy of the parathyroid glands can be observed. There is an indication (Nauwerck) that syphilis can sometimes cause a change in the facial bones similar in appearance to L. o. One must distinguish from L. o. the overgrowth of facial bones observed in acromegaly (see); in the latter, the overgrowth is more uniform, without osteosclerosis and fibrous transformation of the bone marrow. The same can be said about those small hyperostoses of the cranial bones that occur with prolonged venous hyperemia of the head region, for example, in cardiac and pulmonary patients. As for the so-called familial hyperostosis of the jaws, this is a rarely encountered disease, apparently of genotypic origin; it differs from L. o. in that it affects only the jaw and histologically does not coincide with L. o.