Melatonin deficiency and fibrous dysplasia: might a relation exist?

[The experience of interdisciplinary interaction in elimination of midface deformation (clinical observation)]

Fibrous dysplasia is a hamartoma appearing as a benign pathologic process in which normal bone tissue formation is replaced by overgrowth of fibrous connective tissue. The problem of diagnosis and treatment of patients with fibrous dysplasia remains unsolved in the absence of a uniform understanding of its etiology and pathogenesis. Treatment and rehabilitation of patients with midface fibrous dysplasia is a complicated medico-social problem, which requires interaction of specialists of different fields to resolve it. The disease presents a practical interest for doctors of more than 20 specialties, as it can lead to disability. The present article describes a clinical case of interdisciplinary interaction of specialists in the fields of maxillofacial surgery, ophthalmology, otorhinolaryngology, plastic surgery and radiology involved in complex treatment of a patient with midface fibrous dysplasia accompanied by eyeball dislocation, decreased vision, as well as progressive impairment of nasal breathing function. The performed treatment resulted in favorable functional and aesthetic outcomes including elimination of exophthalmos, vertical strabismus, lacrimation disorders, nasal breathing disorders, increase of visual acuity and improvement of external appearance.

The nature of fibrous dysplasia

Fibrous dysplasia has been regarded as a developmental skeletal disorder characterized by replacement of normal bone with benign cellular fibrous connective tissue. It has now become evident that fibrous dysplasia is a genetic disease caused by somatic activating mutation of the Gsα subunit of G protein-coupled receptor resulting in upregulation of cAMP. This leads to defects in differentiation of osteoblasts with subsequent production of abnormal bone in an abundant fibrous stroma. In addition there is an increased production of IL-6 by mutated stromal fibrous dysplastic cells that induce osteoclastic bone resorption.

Skeletal disorders associated with skin pigmentation: a role of melatonin?

Although frequently encountered, no available consensus about the association between skeletal abnormalities and skin pigmentation. Several syndromes are characterized by the presence of skin pigmentation in association with skeletal disorders like neurofibroamtosis 1, McCune-Albright Syndrome, Jaffe-Campanacci Syndrome and Jaffe-Lichtenstein Syndrome. Even in the absence of these syndromes, skeletal abnormalities were detected in all radiologically examined patients having patterned skin pigmentation. Although skin pigmentation is controlled by several factors, melatonin is the most reliable factor to have relation to development of skeletal abnormalities. Recent research works support that melatonin might play a role in bone development and several hypotheses link melatonin with some bone diseases associated with skin pigmentation. It seems that melatonin deficiency is a probable operating co-factor in a lot of clinical situations characterized by skin pigmentation and skeletal disorders. This would explain some of the un-explained observations related to these syndromes and research works along these lines might lead to the development of efficient treatment for these diseases.