Facial Hemihypertrophy - Types, Causes, Symptoms, Diagnosis and Treatment

Introduction:

Developmental defects are not so uncommon nowadays. Anomalies keep happening from time to time with an incidence rate of six percent in the total births worldwide. One such disorder that happens by birth and is not a very frequent condition, is called facial hemihypertrophy. Hemi means half and hypertrophy means an increase in the size of the cells; which explains facial hypertrophy as an increase in the size of one-half of the face. In some, this condition is barely noticeable; whereas in others the features are quite prominent.

What Is Facial Hemihypertrophy?

Facial hemihypertrophy is a rare congenital defect affecting babies. It involves excessive development of the hard and soft tissues of one side of the face which leads to an asymmetrical appearance of the face. This condition appears at birth and keeps getting prominent with age advancement. The affected side grows at the same rate as the other side; leaving no possibility to camouflage the defect. The common structures of the face affected during facial hemihypertrophy include; the bones of the face including the mandible (lower jaw), maxilla (upper jaw), palate, nose, chin, teeth, soft tissues of the face (lips, cheek), tongue, ear, and also the head.

What Are the Types of Hemifacial Hyperplasia?

Hemifacial hyperplasia is classified based on the soft tissue involvement as;

• True Hemifacial Hyperplasia - It involves excessive growth of more than one structure of one side of the face or all the structures of the particular side of the face.

• Partial Hemifacial Hyperplasia - It involves excessive growth of only one of the tissues of the face.

What Are the Other Names for Facial Hemihypertrophy?

Facial hypertrophy is also addressed by the following names;

• Hemifacial hypertrophy.

• Hemimacrosomia.

• Congenital hemifacial hyperplasia.

• Facial hemihyperplasia.

• Partial or unilateral gigantism.

What Are the Causes of Facial Hemihypertrophy?

There is no proper theory that explains the cause of facial hemihypertrophy. So, the cause of this condition still remains unknown. But following are considered the possible causes of facial hemihypertrophy;

• Inherited chromosomal alterations or alterations in the genes could be the cause, but there have been cases reported with no prior history in the family.

• Hormonal dysfunctions.

• Problems encountered during pregnancy that alter the intrauterine atmosphere for the fetus such as infections, drug or alcohol abuse, medications, or problems faced during delivery.

• Blood or nerve-related disorders.

• Consanguineous marriages (getting married to a closely related person such as a second cousin).

What Are the Features of Facial Hemihypertrophy?

The features are not supposedly similar and can vary by one or two features in each case. They vary depending upon the structures involved. Facial hemihypertrophy is associated with evident features like;

• Face: Asymmetry of the face with enlargement on either the right or the left side. Swelling on the affected side.

• Dentition: The abnormalities in the dentition of the affected side are classified based on three factors such as; rate of development, size of the tooth (both crown and root), and shape of the tooth (both crown and root).

1. Reports also suggest that not all the teeth are affected at the same rate as they found the incidence to be more in certain teeth.

2. In the deciduous teeth, second molars are the most commonly affected teeth. Whereas in permanent dentition, canines are the most commonly affected teeth, next on the list are the first molars and premolars.

3. Also, the incidence of congenitally missing teeth, premature eruption, delayed eruption, and early shedding of deciduous teeth are more on the affected side.

4. Palate bone if involved could appear thicker than usual.

5. The tongue might be larger as a whole in some cases.

6. The jawbones could be larger on the affected side.

7. Dental malocclusion involving deviation of the midline and spacing between teeth is common in the patients affected by facial hemihypertrophy.

• Nose: The nose might show deviation towards the affected side.

• Chin: Chin might as well show deviation towards the affected side.

• Ear: If the ear is involved; it might have a different shape and can appear to be larger than the other side.

• Cheek and Lips: The soft tissues of the face such as the cheek and the lips appear thicker and bulkier than usual on the affected side.

What Are the Radiographic Features of Facial Hemihypertrophy?

Radiographic features of facial Hemihypertrophy are unilateral enlargement of all the viscerocranium structures bounded by the frontal bone, excluding the eye, inferiorly by the inferior border of the mandible and the midline and laterally by the ear. The key findings for the diagnosis of hemifacial hypertrophy are enlargement and deformity of all tissues of the face, including teeth and their related tissues in the jaw.

What Is Hemiphyperplasia of the Face?

Hemifacial hyperplasia is a rare congenital developmental disorder which shows asymmetrical overgrowth of one or more body parts. Hemifacial hyperplasia effects the facial soft tissues, bone and the associated structures.

What Are the Symptoms Associated With Facial Hemihypertrophy?

The individuals affected by this condition are otherwise healthy and physically fit in most cases. Due to the abnormalities in the facial structures the patients might encounter difficulties with normal functions such as;

• Disturbances in speech.

• Difficulties in chewing.

• Restriction in the mouth opening and difficulties in closing the mouth properly (open bite).

• Some might experience pain in the jaw.

What Are the Syndromes Associated With Facial Hemihypertrophy?

Facil hemihypertrophy can occur by itself or can be associated with other conditions such as;

• Sturge-Weber syndrome (rare disorder associated with a birthmark on the face).

• Beckwith-Wiedemann syndrome(affected kids are larger in size than others).

• Von Recklinghausen’s neurofibromatosis (a genetic disorder which shows tumors associated with the nerves).

• Klippel-Trenaunay-Weber syndrome (condition affecting the development of soft and hard tissues such as bones).

• Proteus syndrome (condition which shows excess growth of the bones, and other tissues).

• McCune-Albright syndrome (a disorder that affects the bones, skin and the hormone secreating glands).

How Is Facial Hemihypertrophy Treated?

• There is no specific treatment required in facial hemihypertrophy unless there is a cosmetic concern for the patient.

• If the patients requests treatment, it is initiated only after the physiologic growth ends.

• Treatment usually includes; reconstructive surgeries of the jaw, and soft tissue bulk reduction procedures by removing the subcutaneous tissue (fats) without affecting the nerve and its functions.

Conclusion:

Facial hemihypertrophy is not a serious condition that needs to be worried about as there is no reported malignancy associated with this condition. It demands treatment only when the patients feel their appearance to be aesthetically displeasing. Though the treatment planning for this condition might be tedious and lengthy involving multiple surgeries, it is not impossible to do. Thorough analysis and a proper diagnosis of the condition is necessary before undergoing the surgery and if the patient satisfies the demanded criteria for the surgery; there is no restriction to undergoing treatment.