Neurofibromatosis of the maxillofacial region

Khalid A. Al-Ruhaimi, BDS, MSc, Dr Med Dent*
Hermann F. Sailer, Dr Med, Dr Med Dent**
*Oral and Maxillofacial Surgery, Department of Biomedical Dental SciencesCollege of Dentistry, King Saud University
**Oral and Maxillofacial Surgery, Zurich University Hospital & Dental School, Zurich

Neurofibromatosis was first described by Akenside.1 However, Friedrich von Recklinghausen2 was the one who concluded that multiple tumors of nerves and skin (neuromas and fibromas) existed simultaneously and were structurally related, and
thus justified the name neurofibromatosis, which later became known as Recklinghausen's disease.
Recklinghausen's disease is an inherited disease transmitted as an autosomal dominant trait with a positive family history in most cases. It is considered to be one of the most devastating and destructive diseases in mankind.

 In addition to the associated skeletal lesions, neurocutaneous syndrome is characterized by
cutaneous and subcutaneous fibrous tumors of the skin, cafe'au-lait pigmentations, vascular and lymphatic anomalies, neurofibromas of the peripheral  and central nerves. These are in addition to the associated skeletal lesions.

The data for this study was gathered from seventeen patients with neurofibromas in the maxillofacial region. The patients were seen between 1970 and 1987 at the Department of Oral and Maxillofacial Surgery of the Zurich University Hospital.
Cases with inadequate information, or patients whose records could not be traced, were not
included in the study. When diagnosis was made, the patients were analyzed for age, sex, family history of the disease, associated complications and other dis­
eases. Evidence of malignant transformation, clinical site of neurofibromas, associated radiologic findings, and, finally, surgical procedures that were carried out for treating deformities caused by the disease were also noted.

Age, Sex and Family History: 

Table 1 shows the ages of the seventeen patients when diagnosis was made. There was a wide age distribution from 1 to 75 years (mean: 21.5 years). However, the incidence of neurofibromas was slightly higher in females than males. Ten (58.8%) were females and seven (41.2%) were males.

There was positive family history in five patients (29.4%) as shown in Table 1. Types of complications and other associated lesions seen in these patients are presented in Table 2 and they were as follows:

Clinical Sites:

The distribution of the lesions in various anatomical sites is shown in Table 3. All cases of this study were involved unilaterally. The tumor masses affected one or several anatomical locations. However, the lower jaw was involved in 11 (64.7%) out
of the seventeen cases.

Upper jaw lesions were recorded in nine (52.9%) cases. Lips were deformed in six (35.3%) patients. Tumor mass in the nose was evident in
two (11.8%) patients. Cheek was disfigured with hyperplastic masses of the tumor in six (35.3%) patients. Orbit and eyelids were involved in three (17.6%) patients. Unilateral macroglossia was evident in two (11.8%) cases while deformity of the
ear was present in one (5.9%) patient.

Radiologic Findings:

Radiologic findings of this series are listed in Table 4, and skeletal manifestations, in some cases,
are illustrated in Figs. 1 to 4. Skeletal involvements associated with the tumor masses were encountered in 13 (76.4%) cases. These cases were
reported as bony changes in the maxilla, clinically presenting as hypoplasia of the maxilla and maxillary sinus 6 (35.3 %), dental impaction, spacing and displacement of the teeth 5 (29.4%), and outwardly curvature of the zygomatic arch 2(11.8%)

In the mandible the bony changes were found in 12 (70.6%) cases. They were recorded as: hypoplasia and flattening of the contour 10 (58.8%), small condyle and flat glenoid fossa 7 (41.1%), obtuse gonial angle 8 (47.1 %), large funnel-shaped inferior dental canal opening 6 (35.3%), large mental foramen 1 (5.9%), increased depth of the sig­
moid notch 7 (41.1 %), deviation of the mandible 5 (29.4%), intra-osseous cystic formation 6(35.3%), spacing, impaction and displacement of the teeth 10(58.8%).

Orbital involvements were noticed in two (11.8%) cases. The characteristic changes seen were enlargement of the orbit in one (5.9%) case and hypoplastic deformity of the lateral wall, floor, and inferior rim in another case (5.9%)

Surgical Management:

Methods used in the surgical management of these patients are listed in Table 5.The most frequent operative procedure was excision of the tumor mass. Incomplete excision of the tumor lesions was carried out in 11 (84.6%) patients. Complete removal of the mass was done in five (31.3%) patients. One patient failed to present for surgical treatment after being scheduled.

Dental extraction of impacted teeth or surgical release of fibrous hyperplastic tissue from crowns of teeth was carried out on seven (43.8%) cases.

Surgical correction of the facial or occlusal asymmetry included sagittal splitting, genioplasty, and LeFort I osteotomy, in three (17.6%), two (12.5%),
and one (6.3%) patient(s), respectively.

Correction of the nose was performed in one (6.3%) case. Two (12.5%) patients had undergone partial glossectomy for removal of unilateral hyperplastic tissue. One (6.3%) case had radical neck dissection because of evidence of malignant transformation. Parotidectomy was done in one (6.3%) case. Face lifting and eyebrow lifting for improved cosmetic outcome were performed in two (12.5%) cases.

Neurofibromatosis is, by no means, a rare disease although it is not a very common one.It is probably the most common genetic disease in mankind.3 The incidence is recorded in most of the reports as 1 in 3000 live births.4, 5, 6. The age distribution of patients in this study is in the same range reported by others.7, 8. There appears to be no significant difference in the inci­ dence of disease between males and females in this series. In most of the previous reports, the sex ratio was approximately equal.5, 9

Family history may be detected in some instances, and, in our study, it was positive in 5 (29.5%) cases. Other reports have shown inherited transmission in 10 to 50 percent of cases.8,10. The presence of cafe'au-lait spots ordinarily may be normal, but association of clinical and skeletal lesions is considered to be a characteristic diagnos­ tic feature of neurofibromatosis.11

These cutaneous brown spots were found in 14 (82.4%) of our cases in agreement with previous reports.11, 12. Multiple cutaneous nodules are mainly found after puberty and are usually manifestations of long standing or adult disease.13, 14. They were recorded in only 4 of our patients.  Maceri and Saxon9 reported that 66.6% of their 63 patients had these nodules, whereas Crawford12 found only 18% of his 116 children with neurofibromatosis nodules.

Incidence of malignancy is rare with neurofib­ romatosis, although it is, beyond question, part of the disease considerations. It is recorded in only one case of our group. Others8, 15, 16, 17 found malignant frequency of between two and five percent. Mental retardation in patients with neurofibromatosis18 was associated with four of our patients. Psychologic depression10 is a problem of patients with neurofibromatosis due to isolation from the surrounding society. Two of our patients suffered from this problem. Other clinical findings reported by others,10, 19 which we also found in our series, were grandmalepilepsy and iris nodules (one case each).

Hemangiomatous and lymphangiomatous mal­ formations in neurofibromatous lesions are
anomalies of vascular and lymphatic systems con­ tributory to massive bleeding.20-26 However, in our study, four patients did show this problem and
were managed without difficulty. Preliminary ligation of feeding vessels was not considered by us, as advocated by some authors,26 since the procedure increases vascularity by opening up the collateral vessels.

Adekeyeetal17 used boiling water as a sclerosing agent. This caused operative difficulty and post-operative hematoma in 7 of their 28 patients. Intra­ arterial embolisation by introducing strips of lyophilized dura into the main feeding vessels was recommended by Littlewood and Stillwell.27. Frame et al28 suggested the use of Gelfoam and Polyvinyl sponges as embolising agents. However, extensive tamponment packing was used to over­
come spontaneous massive hemorrhage in our cases. It was left in the operative site and removed after approximately two weeks without significant post-operative bleeding. Pressure dressing was applied to reduce post-operative hematoma. The neurofibromatous changes of this series were exclusively unilateral, whereas Vincent and Williams29 reported a rare case of bilateral involvement.

In contrast to the report of Koblin and Reil,25 the lower jaw was the most involved site in our patients (11 out of 17 cases). Occlusal plane distortion and facial asymmetry are common findings with this disease14, 16, 30 and were noticed in 8 of our patients. Tongue is a common site for neurofibromatous lesions,6, 22, 31-32 and two of our patients
presented with unilateral macroglossia. Hyperplastic deformities of other common sites, as reported by other authors,21, 32 were also encountered in this series in the palate and alveolar process, lips, nose, cheek, orbit, and ear. Rather surprisingly, skeletal
lesions were associated with 76.4% of our cases whereas other comparable studies4, 6, 7,9 reported bone lesions in the range of 18-70% of the cases.

All skeletal deformities of our cases were of hypoplastic features. Several authors9, 25, 33-35 drew attention to deformities of the facial bones in patients with neurofibromatosis as hypertrophy, hypoplasia, asymmetry, and radioluscent defects. However, the bony defects in this study which had been reported in various previous studies were recorded as hypoplasia of the maxilla and maxillary sinus, maxillary teeth impaction and spacing,16 hypoplasia of the zygoma with prominent convex­ ity of the zygomatic arch,36 mandibular hypoplasia with flat contour, 14small size of the mandibular condyle and flatness of the glenoid fossa,37 obtuse gonial angle, large funnel-shaped opening of the inferior dental canal, enlargement of the mental foramen,38 increased depth of the sigmoid notch,35 intra-osseous cystic radiolucencies,4, 39, 40, 41 deviation of the mandible,34 mandibular teeth impaction and spacing,25 enlargement of the orbit, and hypoplastic deformities of the lateral wall, floor, and inferior rim.33, 38, 42, 43

Address reprint requests to:

Dr. K.A. Al-Ruhaimi,
Dept. of Biomedical Dental Sciences,
College of Dentistry, King Saud University,
P.O. Box 60169, Riyadh 11545,
Kingdom of Saudi Arabia