Craniofacial and dental manifestations of Proteus syndrome: a case report

Phenotype and Surgical Treatment in a Case of Proteus Syndrome With Craniofacial and Oral Findings

BACKGROUND/AIM

Proteus syndrome is a sporadic disease that is particularly noticeable due to the disproportional growth of body segments. The disease is a genetic mosaic. The mutations can arise from any of the germ layers, an explanation of the very variable phenotype. The aim of this report is to communicate the diagnosis and management of an unusual case of Proteus Syndrome with special attention to oral and craniofacial findings.

CASE REPORT

A 15-year-old patient was referred for surgical treatment of pronounced skull malformations and correction of oral mucosal hyperplasia. Treatment caused significant improvement in facial appearance and oral soft tissue conditions.

CONCLUSION

Surgical measures adapted to the local findings and symptoms can often relieve severe disfigurement of the patient.

Hamartomas of the oral cavity

The majority of oral diseases present as growths and masses of varied cellular origin. Such masses may include simple hyperplasia, hamartoma, choristoma, teratoma, benign or malignant neoplasms. The distinguishing features of hamartomatous lesions are not certain, and often these non-neoplastic masses are indiscreetly denoted as neoplasms without weighing their pathology or biological behaviour. Essentially, understanding the dynamics of each of these disease processes forms an integral part of the appropriate treatment planning.

Missense mutation in the PTEN promoter of a patient with hemifacial hyperplasia

The cellular mechanisms involved in the asymmetric facial overgrowth syndrome, hemifacial hyperplasia (HFH), are not well understood. This study was conducted to compare primary cell cultures from hyperplastic and normal HFH bone for cellular and molecular differences. Primary cultures developed from biopsies of a patient with isolated HFH showed a twofold difference in cell size and cell number between hyperplastic and normal bone. Microarray data suggested a 40% suppression of PTEN (phosphatase-tensin homolog) transcripts. Sequencing of the PTEN gene and promoter identified novel C/G missense mutation (position -1053) in the regulatory region of the PTEN promoter. Western blots of downstream pathway components showed an increase in PKBa/Akt1 phosphorylation and TOR (target of rapamcyin) signal. Sirolimus, an inhibitor of TOR, when added to overgrowth cells reversed the cell size, cell number and total protein differences between hyperplastic and normal cells. In cases of facial overgrowth, which involve PTEN/Akt/TOR dysregulation, sirolimus could be used for limiting cell overgrowth.

Craniofacial and dental development in Costello syndrome

Costello syndrome (CS) is a RASopathy characterized by a wide range of cardiac, musculoskeletal, dermatological, and developmental abnormalities. The RASopathies are defined as a group of syndromes caused by activated Ras/mitogen-activated protein kinase (MAPK) signaling. Specifically, CS is caused by activating mutations in HRAS. Although receptor tyrosine kinase (RTK) signaling, which is upstream of Ras/MAPK, is known to play a critical role in craniofacial and dental development, the craniofacial and dental features of CS have not been systematically defined in a large group of individuals. In order to address this gap in our understanding and fully characterize the CS phenotype, we evaluated the craniofacial and dental phenotype in a large cohort (n = 41) of CS individuals. We confirmed that the craniofacial features common in CS include macrocephaly, bitemporal narrowing, convex facial profile, full cheeks, and large mouth. Additionally, CS patients have a characteristic dental phenotype that includes malocclusion with anterior open bite and posterior crossbite, enamel hypo-mineralization, delayed tooth development and eruption, gingival hyperplasia, thickening of the alveolar ridge, and high palate. Comparison of the craniofacial and dental phenotype in CS with other RASopathies, such as cardio-facio-cutaneous syndrome (CFC), provides insight into the complexities of Ras/MAPK signaling in human craniofacial and dental development.

Proteus syndrome revealing itself after the treatment of a bilateral subdural haematoma

INTRODUCTION

Hypertrophy of the calvarium has different aetiologies, among them the rare Proteus syndrome.

CASE REPORT

We report here the case of a young girl initially treated for relapsing right then left large chronic subdural haematoma, who progressively developed craniofacial hypertrophy consistent with the diagnosis of Proteus syndrome. Calvarium hypertrophy was shaved and remodelled combining midface advancement, essentially for cosmetic purposes. During the first calvarium remodelling, important bleeding of the bone required large volume of blood replacement. Haemostasis workup revealed platelets aggregation anomalies. Bleeding issues during subsequent surgeries were controlled with tranexamic acid and desmopressin acetate.

DISCUSSION

Other manifestations of Proteus syndrome, such as a right hypertrophy of the face with hypoplasia of its middle third, a pigmented epidermal nevus and asymmetric limbs and scoliosis, appeared progressively over time. Blood and fibroblast phosphatase and tensin homolog mutation was not found.

CONCLUSION

Literature review of operated patients with Proteus syndrome did not reveal an association with platelets anomalies. A complete haemostasis workup following this unexpected haemorrhagic complication is recommended for this rare pathology.

Dental approach to craniofacial syndromes: how can developmental fields show us a new way to understand pathogenesis?

The paper consists of three parts. Part 1: Definition of Syndromes. Focus is given to craniofacial syndromes in which abnormal traits in the dentition are associated symptoms. In the last decade, research has concentrated on phenotype, genotype, growth, development, function, and treatment. Part 2: Syndromes before Birth. How can the initial malformation sites in these syndromes be studied and what can we learn from it? In this section, deviations observed in syndromes prenatally will be highlighted and compared to the normal human embryological craniofacial development. Specific focus will be given to developmental fields studied on animal tissue and transferred to human cranial development. Part 3: Developmental Fields Affected in Two Craniofacial Syndromes. Analysis of primary and permanent dentitions can determine whether a syndrome affects a single craniofacial field or several fields. This distinction is essential for insight into craniofacial syndromes. The dentition, thus, becomes central in diagnostics and evaluation of the pathogenesis. Developmental fields can explore and advance the concept of dental approaches to craniofacial syndromes. Discussion. As deviations in teeth persist and do not reorganize during growth and development, the dentition is considered useful for distinguishing between syndrome pathogenesis manifested in a single developmental field and in several fields.

Radiographic manifestations of the temporomandibular joint in a case of Proteus syndrome

Proteus syndrome is a rare disorder with progressive asymmetrical and disproportionate overgrowth of various tissues of the body. The syndrome is characterized by a wide range of malformations, including craniofacial deformities. Extraoral examination revealed several of the classical craniofacial features of Proteus syndrome: pronounced hemifacial hypertrophy, macrodactyly and hyperostosis. Intraoral examination revealed a high arched palate and gingival hyperplasia. Other findings were unilateral enlargement of the tongue, alveolar growth and dilaceration of the roots of the teeth. There were severe degenerative changes and deformities in the left temporomandibular joint but the oversized condyle was asymptomatic; there was no pain, limitation and deviation at mouth opening. Treatment was not necessary owing to the asymptomatic situation but periodic follow-up with clinical and radiographic examination was considered. The aim of this article is to describe the radiographic manifestations of an asymptomatic condyle malformation and other craniofacial, oral and dental findings in a 33-year-old female patient with known Proteus syndrome.

Ossicular Discontinuity and Exostoses in Proteus Syndrome: A Case Report

Proteus syndrome (PS) is a rare hamartomatous disorder characterized by mosaic overgrowth of multiple tissues that manifests early in life and is progressive. The presence of unilateral external auditory canal exostoses in a patient who is not a swimmer or surfer is suggestive of PS. However, hearing loss is not a typical feature. Here, we describe exostoses and ossicular discontinuity with conductive hearing loss in a patient with PS. The treatment consisted of canalplasty and ossicular chain reconstruction. A postoperative reduction was demonstrated in the patient's air-bone gap, from 21 dB to 13 dB for the pure tone average (four frequencies) and from 41 dB to 15 dB in the high-frequency range (6,000 to 8,000 Hz). Causes of ossicular discontinuity are discussed. Routine annual audiometric and otolaryngological evaluation should be considered in all patients with temporal bone inyolvement of PS.