Fibrous dysplasia of the head and neck in Southern Finland: a retrospective study on clinical characteristics, diagnostics, and treatment.

PURPOSE: Fibrous dysplasia (FD) is a rare genetic disease with benign bone tumors. FD can affect one (monostotic FD) or multiple bones (polyostotic FD), with craniofacial lesions being common. Because of its rarity, there are only few clinical reports on FD in the head and neck region and its clinical characteristics remain incompletely defined. This study aimed to determine patient demographics, symptoms, diagnostics, and given treatment in patients with FD of the head and neck in a Finnish population. METHODS: A retrospective review on all patients diagnosed with or treated for FD of the head and neck at the Helsinki University Hospital during 2005-2020. RESULTS: In total 74 patients were identified; 54% were male and the mean age 45 years. Overall 95% had monostotic FD. Mandibula and maxilla were the most common anatomic sites. Majority of patients had symptoms, most commonly pain and lesion growth, and 49% had extra-skeletal symptoms. For all, diagnosis was primarily based on imaging findings, biopsies were obtained from 41%. Altogether 54 patients (73%) were managed by observation only, 20 patients (27%) received treatment; ten bisphosphonates, six surgery and four both. CONCLUSION: Although highly variable in its clinical manifestations, head and neck FD lesions are often symptomatic and impose risk for extra-skeletal complications. Treatment is often conservative but should be individually tailored. Future studies are encouraged to better define the disease characteristics and hopefully offer new treatment possibilities.

Successful Implant Placement in a Case of Florid Cemento-Osseous Dysplasia: A Case Report and Literature Review.

Florid cemento-osseus dysplasia (FCOD) has been described as a reactive process in which normal bone is replaced by fibrous connective tissues and cementum-like materials. Radiographically it appears as dense, lobulated masses, often occurring bilaterally with symmetric involvement. In this case report, a successful implant placement has been reported in a 62-year-old Caucasian woman with a chief complaint of mandibular partial edentulous. Radiographic images showed the bilateral radiopaque lesions in edentulous regions of mandible, and mandibular anterior teeth alike. All mandibular teeth were vital and no root resorption was detected. The findings of X-ray images were attributable to FCOD. A highly conservative step-by-step 2-stage implant surgery was performed. After 6 months the implants loaded with fixed prosthesis. 2, 4, 6, 12, and 18 months after the surgery radiographic images were taken, which revealed an optimal functional rehabilitation and complete integration of implants. This report confirms that treating the edentulous area near the FCOD lesions could be planned, if conservative step- by-step implant placement been considered. To the best of our knowledge, a case of FCOD with successful implant placement has not been reported previously. More studies in more patients are needed to confirm results of such a therapeutic modality.

Diagnosis and management of benign fibro-osseous lesions of the jaws: a current review for the dental clinician.

Benign fibro-osseous lesions of the maxillofacial skeleton constitute a heterogeneous group of disorders that includes developmental, reactive (dysplastic) and neoplastic lesions. Although their classification has been reviewed multiple times in the past, the most common benign fibro-osseous lesions are fibrous dysplasia, osseous dysplasia and ossifying fibroma. For the dental clinician, the challenges involve diagnosis and treatment (or lack thereof). A careful correlation of all clinical, radiologic and microscopic features is essential to establish a proper diagnosis and a clear treatment plan. This article aimed to review the clinical, radiologic and histopathologic characteristics of benign fibro-osseous lesions of the jaws, with emphasis on their differential diagnoses. With a deeper understanding of benign fibro-osseous lesions, clinicians will be better prepared to manage these lesions in their practice.

Fibrous dysplasia of bone: craniofacial and dental implications.

Fibrous dysplasia (FD) is a rare bone disease caused by postzygotic somatic activating mutations in the GNAS gene, which lead to constitutive activation of adenylyl cyclase and elevated levels of cyclic AMP, which act on downstream signaling pathways and cause normal bone to be replaced with fibrous tissue and abnormal (woven) bone. The bone disease may occur in one bone (monostotic), multiple bones (polyostotic), or in combination with hyperfunctioning endocrinopathies and hyperpigmented skin lesions (in the setting of McCune-Albright Syndrome). FD is common in the craniofacial skeleton, causing significant dysmorphic features, bone pain, and dental anomalies. This review summarizes the pathophysiology, clinical findings, and treatment of FD, with an emphasis on the craniofacial and oral manifestations of the disease.

Management of fibro-osseous lesions of the craniofacial area. Presentation of 19 cases and review of the literature.

INTRODUCTION: Fibro-osseous lesions constitute a rare benign type of pathology with a non-odontogenic lineage that affect the craniofacial area. According to Waldrom's classification, these lesions are divided into: fibrous dysplasia (FD), cemento-ossifying fibroma (COF) and desmoplastic fibroma (DF). MATERIAL AND METHODS: A retrospective study was performed on patients diagnosed with fibro-osseous lesions of the craniofacial area at the Hospital Universitario La Fe, Valencia, during 1987-2009. A total of 19 cases were collected: 15 cases compatible with an FD diagnosis, 3 cases with a COF diagnosis and 1 case with a DF diagnosis. RESULTS: In the differential diagnosis, entities having similar clinical manifestations in the maxillofacial area with possible involvement of teeth or manifestations present as an asymptomatic radiolucent image should be ruled out. We hereby present the management and development of patients treated in our hospital for fibro-osseous lesions. CONCLUSIONS: Fibro-osseous lesions share many clinical and radiological characteristics in common, with histological features confirming the nature of the lesion. Management of patients should be individualized and case-specific, assessing the clinical evolution of each case and taking into account the benign nature and growth behavior of this type of tumors.

Function after injection of benign bone lesions with a bioceramic.

BACKGROUND: A novel calcium sulfate-calcium phosphate composite injectable bone graft substitute has been approved by the FDA for filling bone defects in a nonweightbearing application based on preclinical studies. Its utility has not been documented in the literature. QUESTIONS/PURPOSES: We therefore determined postoperative function and complications in patients with benign bone lesions treated with this bioceramic. METHODS: We retrospectively reviewed all 56 patients with benign bone lesions treated with the bioceramic from 2006 to 2008. There were 29 male and 27 female patients with an average age of 17.6 years (range, 4-63 years). They were treated for the following diagnoses: unicameral bone cyst (13), aneurysmal bone cyst (10), nonossifying fibroma (eight), fibrous dysplasia (five), enchondroma (four), chondroblastoma (four), and other (12). We obtained a Musculoskeletal Tumor Society (MSTS) functional evaluation on all patients. The minimum followup was 26 months (average, 42 months; range, 26-57 months). RESULTS: The average MSTS score was 29 (range, 20-30). Most patients returned to normal function. There were three local recurrences, all of which were treated with repeat injection or curettage. Two patients had postoperative fractures treated in a closed manner. Two patients had wound complications, neither of which required removal of the graft material. CONCLUSION: Patients treated with this material reported high MSTS functional scores more than 24 months after operative intervention and experienced low complication rates. We believe the novel bioceramic to be a reasonable treatment option for benign bone lesions.

Chronic non-bacterial osteomyelitis masquerading as fibrous dysplasia.

Chronic non-bacterial osteomyelitis is a rare auto-inflammatory bone disease seen predominantly in the paediatric population. We describe a unique case of a 30-year-old female who presented with right-sided jaw pain and intermittent swelling over the course of 6 years. She was initially treated with antibiotics for possible osteomyelitis, then temporarily diagnosed with fibrous dysplasia. She underwent extensive investigations consisting of an infectious workup, numerous imaging modalities, and three separate biopsies of her right jaw. She was ultimately diagnosed with chronic non-bacterial osteomyelitis based upon her history of recurrent episodes of painful swelling, response to non-steroidal anti-inflammatories, previously raised acute phase reactants, and magnetic resonance imaging findings. Unfortunately, she became refractory to non-steroidal anti-inflammatory therapy. Consequently, she was successfully treated with pamidronate, achieving clinical remission with improvement in her imaging findings. This case highlights the difficulty of diagnosis of chronic non-bacterial osteomyelitis and the need for increased awareness of the disease in the adult population. Additionally, the effective treatment with pamidronate supports the use of a bisphosphonate as an early intervention for adult-onset chronic non-bacterial osteomyelitis in patients who have failed non-steroidal anti-inflammatory therapy.

[Progress in the diagnosis of florid cemento-osseous dysplasia].

Florid cemento-osseous dysplasia (FLCOD) is a rare, extensive bone metabolism disorder, which occurs only in the jaw bone. It is usually asymptomatic for a long time and discovered incidentally during a radiological examination. The characteristics of FLCOD in the initial stages are similar to those of periapical granuloma or jaw cyst, which may lead to misdiagnosis. After the lesion is mature, the imaging findings show that radiopaque with a thin radiolucent peripheral halo, which is crucial for the diagnosis of FLCOD, but other jaw lesions have similar imaging findings. Due to the poor blood supply of the lesion, the alveolar bone of root apices of vital teeth is slow to heal after trauma, increasing the chance of infection, which can lead to the osteomyelitis of the jaws and emerge sequestrum. This paper reviews the aspects of pathogenesis, clinical characteristics, diagnosis, differential diagnosis and treatment.

Maxillofacial fibrous dysplasia: a diagnostic challenge.

A 30-year-old woman presented for orthodontic treatment, with a chief symptom of a 'shifting bite' and concurrent facial asymmetry with aesthetic concerns. The patient had previously received treatment from several general dentists and several specialists, without accurate diagnosis. Radiological investigation coupled with biopsy confirmed a diagnosis of fibrous dysplasia. Proper diagnosis led to changes in the treatment plan and gave the patient realistic expectations about the options she had for the outcome of treatment. Prompt diagnosis by dental practitioners is critical to patient satisfaction and successful outcome; therefore, it is important to familiarise ourselves with the signs, symptoms and proper course of management of fibrous dysplasia.

[Florid osseous dysplasia: Management of a symptomatic case]. / Dysplasie osseuse floride : gestion d'un cas symptomatique.

INTRODUCTION: Florid osseous dysplasia is a rare and benign fibro-osseous pathology, in which bone is replaced by fibrous tissue and metaplastic bone. It can remain asymptomatic for a long time and is most often discovered incidentally during a radiological examination. Sometimes, patients are seen because of an infectious complication. OBSERVATION: An edentulous 62 years-old woman was referred for a painful mandibular swelling preventing insertion of her removable denture. Clinical examination showed a chin swelling, a deformation of mandibular bone tables of approximately four centimeters in diameter, an intra-oral fistula and a suppuration. Radiological examination showed a mixed bone lesion blowing up the buccal and lingual cortical plates and a bone sequestrum. Blood test was normal and there were no other skeletal abnormalities. The diagnosis of florid osseous bone dysplasia was made thanks to the confrontation of the clinical, radiological and histological examinations. Excision of the bone sequestrum associated to remodeling osteoplasty was performed under general anesthesia. The removable denture was rebased to drivehealing. DISCUSSION: Surgical management of osseous bone dysplasia is legitimate only in the presence of complications not responding to medical treatment. In all other cases, therapeutic abstention and long term supervision are essential.

A rare case of unilateral fibrous dysplasia of the condyle of the mandible. Diagnosis and therapy using an axiographic technique and digital X-ray ­ a case report.

Introduction: The aim of the paper is to present the diagnostic procedure and treatment of a female patient with dysfunction of the right temporomandibular joint, caused by fibrous dysplasia of the head of the right mandibular condyle. Material and methods: In the diagnostic process of bony structures digital radiography (Digora) was used. To examine the mobility of the mandible axiographic measurements were performed using the Cadiax (Gamma Diagnostic) device. Conclusions: These methods allowed the confirmation of the diagnosis and the determination of a treatment plan which included the use of a therapeutic appliance. The performed procedures had a positive therapeutic effect.

Infected florid osseous dysplasia: clinical and imaging follow-up.

Florid osseous dysplasia (FOD) is a rare fibro-osseous lesion of the jaw usually identified incidentally on radiograph. It rarely presents with clinical symptoms. A case of FOD presenting with features similar to osteomyelitis is discussed here. The diagnosis is based on radiographic findings; biopsy or surgical intervention should be avoided as it may predispose to infection.

Conservative Treatment of Chronic Osteomyelitis Associated with Florid Osseous Dysplasia / Tratamiento Conservador de la Osteomielitis Crónica Asociada con Displasia Ósea Florida

ABSTRACT: Florid osseous dysplasia (FOD) is an extensive form of osseous dysplasia where normal trabecular bone is substituted by fibrous connective tissue and amorphous mineralized tissue. Usually, the lesions are mainly asymptomatic and the patients should be followed with clinical and imaging examination, requiring no intervention. Nevertheless, due to the poor vascularization of the lesion and to local trauma, secondary infections and osteomyelitis may occur. Patients may present with pain, mucosal ulceration, lesion exposure in the oral cavity, fistula and swelling. In such cases, the correct diagnosis and management of the lesion is decisive to reestablish patient's health and quality of life. The aim of this article is to present a case of complicating secondary chronic osteomyelitis treated successfully with conservative intervention. A 68-year-old black female patient reported a "swelling of the gums" that was present for eleven years, with episodes of periodic pain and swelling. On physical examination, a papule with suppuration in the alveolar mucosa in the right side of the mandible was observed. Panoramic radiography and CBCT showed a mixed lesion surrounded by sclerotic bone. The patient was diagnosed with chronic osteomyelitis in association with FOD and treated with antibiotic therapy together with surgical curettage. The incidence, etiophatology, differential diagnosis, treatment and prevention of secondary osteomyelitis associated with FOD are discussed in the light of literature. This information might assist the dentists while choosing the best treatment options for similar cases.

RESUMEN: La displasia ósea florida (DOF) es una forma de displasia ósea donde el hueso trabecular normal es sustituido por tejido conectivo fibroso y tejido mineralizado amorfo. En general, las lesiones son de origen asintomático y los pacientes deben ser seguidos con el examen clínico. Sin embargo, debido a la pobre vascularización de la lesión y al trauma local, pueden producirse lesiones secundarias y osteomielitis. Los pacientes pueden presentarse con dolor, ulceración mucosa, lesión de exposición en la cavidad oral, fístula y edema. En estos casos, el correcto diagnóstico y tratamiento de la lesión es decisivo para reestabilizar la salud y la calidad de la vida. El objetivo de este artículo consistió en presentar un caso de complicación secundaria crónica de osteomielitis tratados con tratamiento conservador. El paciente, negro, de 68 años de edad, consulta por "hinchazón de las encías" que se presentó durante once años, con episodios de dolor. En el examen intraoral, se observó una pápula con supuración en la mucosa alveolar en el lado derecho de la mandíbula. La radiografía panorámica y CBCT mostraron una lesión mixta rodeada de hueso esclerótico. El paciente fue diagnosticado con osteomielitis crónica en asociación con DOF y fue tratado con tratamiento antibiótico junto con curetaje quirúrgico. La incidencia, la etiopatología, el diagnóstico diferencial, el tratamiento y la prevención de la osteomielitis secundaria asociada con DOF se discuten a la luz de la literatura. Esta información puede ayudar a los dentistas a elegir las mejores opciones de tratamiento para casos similares.

Displasia cemento-óssea florida: relato de dois casos tratados por diferentes abordagen / Florid cemento-osseous dysplasia: report of two cases treated with different approaches

Objetivo: relatar dois casos de displasia cemento-óssea florida, descrevendo a evolução clínico-radiográfica ao longo de 5 anos em um paciente assintomático e a abordagem cirúrgica em um caso sintomático. Relato de caso 1: paciente, melanoderma, sexo feminino, 56 anos de idade, encaminhada ao Serviço de Cirurgia Bucomaxilofacial da Universidade Federal da Bahia, por cirurgião-dentista clínico que notou alterações imagiológicas em radiografia panorâmica de rotina. Apesar da importante extensão da lesão em maxila e mandíbula, não havia qualquer sintoma ou sinal clínico de infecção. A paciente foi acompanhada durante 5 anos, com exames de imagem bianuais e medidas clínicas profiláticas. Relato de caso 2: paciente, melanoderma, sexo feminino, 57 anos, apresentou-se ao ambulatório de cirurgia queixando-se de atraso em cicatrização após remoção de um dente. A radiografia panorâmica e a tomografia computadorizada, em conjunto com dados clínicos, permitiram o diagnóstico de displasia cemento-óssea florida com infecção secundária. A paciente foi abordada por meio de osteotomia em região do defeito em mandíbula. A análise microscópica do espécime obtido confirmou a alteração displásica cementoide. Os sinais e sintomas regrediram e a paciente segue em acompanhamento. Considerações finais: a displasia cemento-óssea florida, portanto, é uma doença pouco frequente, cujas manifestações podem demandar diferentes abordagens. É importante o domínio clínico do cirurgião-dentista, uma vez que o diagnóstico equivocado pode guiar a escolhas terapêuticas com resultados insatisfatórios. (AU)

Objective: the objective of this article is to report two cases of florid cemento-osseous dysplasia describing the clinical-radiographic evolution over 5 years in an asymptomatic patient and the surgical approach in a symptomatic one. Case report 1: patient, melanoderma, female, 56 years old, referred to the service by a clinical Dentist who noticed imaging alterations in a routine panoramic radiography. Despite the important extension of the maxillary and mandibular lesion, there was no clinical sign or symptom of infection. The patient has been followed for 5 years with biannual imaging exams and prophylactic clinical measures. Case report 2: patient, melanoderma, female, 57 years old, presented to the surgery outpatient complaining of delay in healing after removal of a tooth. Panoramic X-ray and Computed Tomography together with clinical data allowed the diagnosis of florid cemento-osseous dysplasia with secondary infection. The patient was approached through osteotomy in the region of the mandible defect. The microscopic analysis of the specimen confirmed the dysplastic cementenoid alteration. Signs and symptoms regressed and the patient is in follow up. Final considerations: florida cementoosseous dysplasia is an infrequent disease, whose manifestations may require different approaches. The clinical domain of the Dentist is important, since misdiagnosis can lead to therapeutic choices with unsatisfactory results. (AU)

Fibrous dysplasia of the nasal bone: case reports and literature review.

INTRODUCTION: Craniofacial fibrous dysplasia commonly affects the larger mandible and the maxillary bones. Although involvement of the frontal, temporal and sphenoid bones has been described, fibrous dysplasia of the nasal bone has not been previously described; the two cases reported here have been made rarer by their isolated involvement. Clinical management is dependent on disease activity and patient symptoms. OBJECTIVE: To present two cases of isolated fibrous dysplasia of the nasal bone: a 46-year-old woman with gradual widening of the nasal bridge and a 47-year-old man with an incidental finding of a nasal bone mass. METHOD: Two case reports. RESULTS: The 46-year-old woman underwent excision of the lesion while the 47-year-old man opted for watchful waiting. CONCLUSION: We have presented the first case reports of fibrous dysplasia of the nasal bone. The care of these patients should be customised to their needs and wishes.

Characterization of a biodegradable coralline hydroxyapatite/calcium carbonate composite and its clinical implementation.

A partially converted, biodegradable coralline hydroxyapatite/calcium carbonate (CHACC) composite comprising a coral calcium carbonate scaffold enveloped by a thin layer of hydroxyapatite was used in the present study. The CHACC was characterized using powder x-ray diffraction, scanning electron microscopy and energy dispersive x-ray spectroscopy. The ability of the CHACC to promote conductive osteogenesis was assessed in vitro using human mesenchymal stem cells (hMSCs) and in vivo using an immunodeficient mouse model. The clinical performance of CHACC as a bone substitute to fill voids caused by excision of bone tumours was also observed in 16 patients. The CHACC was found to consist of two overlapping layers both morphologically and chemically. Hydroxyapatite formed a thin layer of nanocrystals on the surface and a thick rough crystal layer of around 30 µm in thickness enveloping the rock-like core calcium carbonate exoskeletal architecture. hMSCs cultured on CHACC in osteogenic medium demonstrated significant osteogenic differentiation. After subcutaneous implantation of CHACC incorporating osteogenically differentiated hMSCs and an anti-resorptive agent, risedronate, into an immunodeficient mouse model, bone formation was observed on the surface of the implants. Clinical application of CHACC alone in 16 patients for bone augmentation after tumour removal showed that after implantation, visible callus formation was observed at one month and clinical bone healing achieved at four months. The majority of the implanted CHACC was degraded in 18-24 months. In conclusion, CHACC appears to be an excellent biodegradable bone graft material. It biointegrates with the host, is osteoconductive, biodegradable and can be an attractive alternative to autogenous grafts.

Diagnóstico y tratamiento de displasia fibrosa madura complicada con osteomielitis crónica. Reporte de caso / Diagnosis and treatment of mature fibrous dysplasia complicated by chronic osteomyellitis. Case report

La displasia fibrosa es una lesión congénita, lentamente progresiva que puede provocar graves alteraciones morfológicas y funcionales, y estar sujeta a complicaciones de tipo infeccioso. En este reporte de caso se presenta a un paciente masculino de 8 años de edad diagnosticado con una displasia fibrosa madura luego de un hallazgo incidental durante un examen de rutina, el paciente durante el curso de los últimos cinco años ha presentado osteomielitis a repetición en el sitio de biopsia y de exfoliación dentaría, el cuadro clínico se ha tratado mediante curetajes y aseos quirúrgicos y con la indicación antibiótica de clindamicina sin resultados positivos. Se concluye que el manejo de las displasias fibrosas maduras puede ser difícil una vez que se ha instalado un proceso infeccioso crónico sin poder dar de alta al paciente, manteniéndolo permanentemente en control. (AU)

Fibrous dysplasia is a slowly progressive congenital lesion that can cause serious morphological and functional alterations , and complications of infectious type . This case report presents a 8 years old male patient diagnosed with a mature fibrous dysplasia after an incidental finding during a routine examination, the patient during the course of the last five years has been presented recurrent osteomyelitis episodes in the biopsy site and temporal tooth during exfoliation, it has been treated by surgical curettage and clindamycin with no positive results. We conclude that the management of mature fibrous dysplasia can be difficult once a chronic infectious process has been installed without being able to discharge the patient, constantly keeping it in control.(AU)

Fibrous dysplasia: a systematic review.

OBJECTIVES: To evaluate the principal features of fibrous dysplasia (FD) by systematic review (SR) and to compare their frequencies between four global groups. METHODS: The databases searched were the PubMed interface of Medline and LILACS. Only those reports of FD which occurred in a series in the reporting authors' caseload were considered. All cases were confirmed fibro-osseous lesions histopathologically. The SR-included series must also have included radiographs. RESULTS: Of the 106 reports considered (including the Hong Kong report), 31 reports and a total of 788 cases were included in the SR. 11 SR-included series were in languages other than English. FD affected both genders equally, but was 50% more prevalent in the maxilla. The mean age at first presentation was 24 years. The decade with the greatest frequency was the second, in which males accounted for 63%. The main symptom in 90% of all SR-included cases was swelling (including deformation of the jaws). Not one SR-included case directly involved the ocular apparatus. All cases displayed buccolingual expansion; all mandibular cases exhibited downward displacement of the lower border of the mandible and almost all maxillary cases involved the maxillary antrum. Only 35% of reports included follow-up; 18% of cases recurred or were reactivated. Not one case displayed sarcomatous change. CONCLUSIONS: Long-term follow-up of large series that would have revealed the long-term outcomes of FD was lacking. This is necessary because many cases do not burn out at the end of adolescence, as expected of a hamartoma, but are reactivated.

[Fibrous dysplasia of maxilla and the orthodontic treatment. Case report]. / Dysplazja wlóknista w obrebie szczeki a leczenie ortodontyczne. Opis przypadku.

INTRODUCTION: Patients who have malocclusions caused by bone diseases come to see the dentist for the orthodontic treatment. One of these diseases is fibrous dysplasia. The aim of this study was to present the patient with the active form of fibrous dysplasia who reported to the Orthodontic Department of Pomeranian Medical University in Szczecin for treatment. MATERIAL AND METHODS: We used the patient's own documentation, photos, radiological view and histopathological investigations. RESULTS: The extraoral, clinical examination revealed the asymmetry of the face on the left side, while the intraoral examination showed the convex lesion similar to an egg on the palate which crosses the medial line and clear "distension" of the alveolar bone in the direction of the oral vestibule. The dysplastic lesions are extensive and cause numerous malocclusions and disorders of the symmetry. The radiological and histopathological examinations were added to the clinical examination. The panoramic radiographs have shown the asymmetry and heterogenic structure of the bone with areas of"ground glass". Computer tomography demonstrated bumpy thickening of the zygomatic bone, maxilla, and a great wing of the sphenoid bone and almost completely filled maxillary sinus. The histopathological examination is the confirmation of the diagnosis of fibrous dysplasia. It demonstrates immature bone. CONCLUSIONS: The diagnosis of fibrous dysplasia commands the periodic observation and the postponement of the orthodontic treatment in the stage of active development of lesions, but when the overgrowth impairs the function, there is the necessity to use surgical and radical excision to remove lesions. We must pay particular attention to the possibility of malignant transformation of these lesions.