This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and

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2 Int. J. Oral Maxillofac. Surg. 2009; 38: doi: /j.ijom , available online at Case Report Head and Neck Oncology Ameloblastic fibroodontosarcoma: a case report P. Mainenti, G. S. Oliveira, J. B. Valério, L. S. L. Daroda, R. F. Daroda, G. Brandão, L. E. B. Rosa: Ameloblastic fibro-odontosarcoma: a case report. Int. J. Oral Maxillofac. Surg. 2009; 38: # 2008 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. This paper reports one case, of an ameloblastic fibro-odontosarcoma (AFOS) affecting the mandible, in a 12-year-old girl. This neoplasm is a rare odontogenic neoplasm. To the authors knowledge this is the fifteenth case of AFOS reported in English. The patient s chief complaint was a swelling in the face for 6 months. An incisional biopsy was performed diagnosing the case as an ameloblastic fibroma. After radiography ameloblastic fibro-odontoma was diagnosed. Computed tomography was performed and a stereolithography model made to plan the surgical procedures. A hemimandibulectomy followed by a vascularized fibular flap was then proposed. The surgery was uneventful. Microscopic features diagnosed an AFOS. After 23 months of close follow-up there is no sign of recurrence or metastasis. Dental implants were recently placed in the fibular flap. P. Mainenti 1,4,5, G. S. Oliveira 1, J. B. Valério 2, L. S. L. Daroda 3, R. F. Daroda 3, G. Brandão 4, L. E. B. Rosa 5 1 Department of Oral and Maxillofacial Surgery, Hospital Nove de Julho - Instituto Oncológico de Juiz de Fora, Rua Santos Dumont, 56 Centro, Juiz de Fora (MG) , Brazil; 2 Department of Head and Neck Surgery, Hospital Nove de Julho - Instituto Oncológico de Juiz de Fora, Rua Santos Dumont, 56 Centro, Juiz de Fora (MG) , Brazil; 3 Department of Plastic Surgery, Hospital Nove de Julho - Instituto Oncológico de Juiz de Fora, Rua Santos Dumont, 56 Centro, Juiz de Fora (MG) , Brazil; 4 Department of Pathology, Santa Casa de Misericórdia de Juiz de Fora, Av. Barão do Rio Branco, Centro, Juiz de Fora (MG) , Brazil; 5 Department of Oral Pathology, Universidade Estadual Paulista - UNESP, Engenheiro Francisco José Longo, 777, São José dos Campos (SP) , Brazil Keywords: ameloblastic fibro-odontosarcoma; hemimandibulectomy; reconstruction; fibula; stereolithography. Accepted for publication 24 November 2008 Available online 15 January 2009 The 2005 World Health Organization classification of odontogenic sarcomas presented 2 entities: ameloblastic fibrosarcoma (AFS); and ameloblastic fibrodentinosarcoma (AFDS) and/or fibroodontosarcoma (AFOS). The first is a tumor with a benign epithelial and a malignant ectomesenchymal component, the second a neoplasm with features of AFS associated with dysplastic dentin and/or enamel/enameloid and dentin/dentinoid 2. AFS is a rare tumor 1,5,6,7 and probably shares the same biological behavior as AFDS and AFOS 1,2,5. It is thought that AFS are the malignant counterparts of ameloblastic fibroma (AF) 1,3,6,9. The tumor can arise in a pre-existing AF or can present de novo 1 3,6,7,9. One-third of the reported cases have developed in recurrent AF 1,6. Despite the local aggressiveness, metastases are not expected 1 3,5,6. This paper reports the case of an AFOS developing in an AF. The surgical procedure and the histological features are presented, including patient follow-up and the use of dental implants for rehabilitation. Case report A 12-year-old girl was referred to the Oral and Maxillofacial Surgery Service at Hospital Nove de Julho (Instituto Oncológico), Juiz de Fora (MG), Brazil, in June 2006, with a left facial swelling and a complaint of 6 months mild pain due to masticatory trauma in the gum. Oral examination revealed a fixed and protruding mass, tender to palpation and covered with a whitish and red mucosa and pseudomembrane (Fig. 1). Orthopantomography revealed a poorly defined radiolucency extending from the left bicuspid to the molar region, an unerupted tooth and calcified material (Fig. 2). An incisional biopsy disclosed a mixed epithelial and mesenchymal cellular neoplasm. The lesion was diagnosed as an / $30.00/0 # 2008 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

3 290 Mainenti et al. Fig. 1. Intraoral view on admission to hospital. AF. The sum of radiographic features and histopathology suggested an ameloblastic fibro-odontoma (AFO). Computed tomography revealed a radiolucent lesion in the left mandible with evidence of a retained molar associated with dense focal radiopacity. A stereolithography model was made to plan the surgical procedure and to guide the bending of the titanium plates. A hemimandibulectomy followed by reconstruction was planed because of the size of the tumor, the mandibular destruction and to minimize the patient s morbidity after the surgery. Under general anesthesia, the patient was operated on by 3 teams (Oral and Maxillofacial Surgery, Head and Neck Surgery, Plastic Surgery). Intermaxillary fixation was performed using Erich s splints and wires to hold the occlusion in a centric position. Through a neck incision, a sub-platysmal dissection created an apron flap. The lesion was then exposed and excised, with inclusion of the oral mucosa, by a left hemimandibulectomy. The condyle was preserved. One titanium reconstructive plate, bent previously, was adapted to bridge the defect, achieving optimal contour (2.4 System, MDT, Brazil). A vascularized fibular flap was transplanted to the site and fixed with two titanium miniplates (2.0 System, MDT, Brazil) and wires. The fibular vessels were sutured to the facial artery and to the external jugular vein. All surgical wounds were closed in layers. The donor site was sutured and a cast was applied. The patient s recovery was uneventful and she was discharged after 5 days. Ten days after surgery, the patient underwent 99m Tc scintigraphy. It showed normal mandibular blood flow and uptake fully compatible with the surgery. Histological examination showed a biphasic neoplasia with areas of epithelial Fig. 2. Orthopantomographic view revealing the left mandibular radiolucency associated with an unerupted tooth and hard tissues. and mesenchymal elements (Fig. 3). The epithelial component combined strands and buds with peripheral layer of cells exhibiting reverse nuclear polarity. In some fields, the connective element consisted of stellate cells resembling normal fibroblasts. Other fields presented a solid stroma with cellular atypia, nuclear pleomorphism and numerous mitotic figures (Fig. 4). Structures resembling dentinal tubules and immature enamel formation were noted. These patterns were recognized as an AFOS arising in a pre-existing AFO. All surgical resection margins were free of tumor. Despite the malignant presentation, chemotherapy has not been used because its use is controversial. After 12 months follow-up the graft was in place and the occlusion was maintained (Fig. 5). After 23 months of close follow-up there is no sign of recurrence or metastasis. Recently, dental implants were placed in the fibular flap. The donor site recovered uneventfully and the patient walks without problems. Discussion AFS are rare, true, mixed neoplasms exhibiting a benign epithelial component and malign ectomesenchymal cells 2,3,6,7,9. Some authors consider that AFS are the malignant counterparts of the AF 1,3,6,9. AFO are considered possible precursor lesions for AFDS and AFOS 2. CARLOS et al. 2 state that, 64 cases of AFS and 14 cases of AFDS/ AFOS have been reported in the English-language literature, up to To the authors knowledge, the case presented here is the fifteenth case of AFDS/AFOS published in English. It is the fifth case in a female patient. Table 1 presents the characteristics of AF, AFS and related lesions. The diagnosis of AFS is made histologically; 6 some features of the mesenchymal pattern, such as cellularity, cellular atypia, mitosis and palisading patterns must be observed as well as the possible step-wise progression of benign to malignant presentation. The first biopsy taken from this case showed only the benign profile of the tumor. Histological evaluation of the whole specimen revealed dentin, enamel and atypical stroma with mitotically active cells. These findings led the authors to recognize an AFOS arising in a preexisting AFO. The case presented here was not microscopically striking so no immunohistochemical markers were used. Nevertheless, other cases might require

4 Ameloblastic fibro-odontosarcoma: a case report 291 Fig. 3. Mixed tumor disclosing benign epithelial tissue surrounded by atypical cellularity. Hematoxylin & Eosin, 630. Fig. 4. Malignant stroma disclosing cellular and nuclear polymorphism. Hematoxylin & Eosin, Fig. 5. Orthopantomography showing titanium plates maintaining the fibular graft and occlusion after 6 months follow-up. adjuvant diagnostic tools. Although scarce, immunohistochemical staining reports could provide information about tumor growth and behavior. The study of Ki-67 3,9, p53 3,6 and PCNA 6,9 showed immunolocalization in the connective tissue of the AFS, revealing a high growth profile in the mesenchymal component, not evident in AF. Poorly differentiated tumors tend to show greater stromal cellularity with a decrease in the epithelial component 2,3,5,9. LEE et al. 7 described cytokeratin immunostaining as a helpful key in identifying epithelial nests, excluding pure sarcomas. They also reported that mesenchymal cells of AFS showed diffuse and moderate expression of CD34. Although malignant, AFS rarely metastasizes 2,3. Fatal cases are associated with uncontrolled local tumor infiltration after numerous recidivations 3. Some of the recurrences are linked to curettage or enucleation of a previously diagnosed AF 6. According to KOBAYASHI et al. 6, 20% of the patients treated for AFS died within 3 months to 19 years, due to locally aggressive tumor growth. In the 12 months after the present patient s surgery, there was no sign of recurrence or metastasis. A surgical protocol with wide resection was used in accord with published reports and has the best prognosis 3,7. Microscopically there were no signs of tumor infiltration in the surgical resection margins. The use of titanium plates, bent before the surgery, helped to preserve the patient s facial contour, masticatory function and teeth occlusion. Shaping the plates before surgery reduced the operating time 4. Healing was uneventful. Scintigraphy, performed 10 days after surgery, and post-surgical radiographs allowed close follow-up for 23 months. The patient is now undergoing dental implant treatment. In conclusion, the authors present a case similar to others, with some peculiar aspects. The malignization of a benign lesion suggests an unexpected profile and a brief evolution of the case. At diagnosis, the mean age of AF is 14.8 years 5. For AFS, arising in a pre-existing AF, the mean age is 33 years. In the present case, an AFOS arising in an AFO, occurred in a 12-year-old girl. The authors agree with BREGNI et al. 1, CARLOS et al. 2, HAYASHI et al. 5 and LEE et al. 7 that AFS have the same biological behavior as AFDS and AFOS. The difference between them is the formation of tooth-like structures. An AFO can change its profile to a malignant tumor, such as an AFS or AFDS/ AFOS, therefore it is advisable to investigate all cases of AF/AFO because they can disguise a malignant tumor.

5 292 Mainenti et al. Table 1. Characteristics of AF, AFS and related lesions. AF AFD AFO AFS AFDS/AFOS Gender predilection Males Males no predilection Males Males Mean age 14.8 years 14.8 years 8-12 years 27.5 years 30 years Age range 7 weeks 62 years 7 weeks 62 years X 3 83 years years Rarity Rare Rare Less common than Very rare Very rare AF/AFD Anatomic Mainly in the Posterior mandible None Posterior mandible X predilection posterior mandible Clinical features Asymptomatic Asymptomatic Asymptomatic Swelling and pain Asymptomatic, swelling Imaging radiolucency; malpositioned tooth radiolucency; malpositioned tooth; radiolucency; uni or multilocular; Ill-defined radiolucency Ill-defined radiolucency; dental hard tissues; radiopacities radiopacities radiopacities Odontogenic Benign Benign Benign Malign Malign ectomesenchyme Epithelial strands Benign Benign Benign Benign Benign and buds Dental structures No Dysplastic dentin Dental hard No Dental hard structures structures Treatment Enucleation and Enucleation and X Wide surgical resection Wide surgical resection Prognosis curettage Rare malignant progression curettage Rare malignant progression Excellent Recurrence without distant metastasis Recurrence without distant metastasis AF, ameloblastic fibroma; AFD, ameloblastic fibrodentinoma; AFO, ameloblastic fibro-odontoma; AFS, ameloblastic fibrosarcoma; AFDS, amelobasitic fibrodentinossarcoma; AFOS, ameloblastic fibro-odontosarcoma; X, no data from consulted authors. BREGNI et al. 1 (2001); CARLOS et al. 2 (2005); de PAULA et al. 3 (2003); KOBAYASHI et al. 6 (2005); TAKEDA 9 (1999); TAKEDA &TOMICH 10 (2005); SLOOTWEG 8 (2005). References 1. Bregni RC, Taylor AM, Garcia AM. Ameloblastic fibrosarcoma of the mandible: report of two cases and review of the literature. J Oral Path Med 2001: 30: Carlos R, Altini M, Takeda Y. Odontogenic sarcomas. In: Barnes L, Eveson Pathology and Genetics of the Head and Neck Tumors. Lyon: IARC Press 2005: de Paula AMB, Neto JQC, Gusmão ES, Santos FBG, Gomez RS. Immunolocalization of the p53 protein in a case of ameloblastic fibrosarcoma. J Oral Maxillofac Surg 2003: 61: Hannen EJM. Recreating the original contour in tumor deformed mandibles for plate adapting. Int J Oral Maxillofac Surg 2006: 35: Hayashi Y, Tohnai I, Ueda M, Nagasaka T. Sarcomatous overgrowth in recurrent ameloblastic fibrosarcoma. Oral Oncology 1999: 35: Kobayashi K, Murakami R, Fujii T, Hirano A. Malignant transformation of ameloblastic fibroma to ameloblastic fibrosarcoma: case report and review of the literature. J Cranio-Maxillo-Facial Surg 2005: 33: Lee OJ, Kim HJ, Lee BK, Cho KJ. CD34 expressing ameloblastic fibrosarcoma arising in the maxilla: a new finding. J Oral Pathol Med 2005: 34: Slootweg PG. Ameloblastic fibroma/ fibrodentinoma. In: Barnes L, Eveson Pathology and Genetics of the Head and Neck Tumors. Lyon: IARC Press 2005: Takeda Y. Ameloblastic fibroma and related lesions: current pathology concept. Oral Oncology 1999: 35: Takeda Y, Tomich CE. Ameloblastic fibroma-odontoma. In: Barnes L, Eveson Pathology and Genetics of the Head and Neck Tumors. Lyon: IARC Press 2005: 309. Address: Pietro Mainenti Department of Oral and Maxillofacial Surgery Centro Médico Rio Branco Av. Barão do Rio Branco 1034 Centro Juiz de Fora (MG) Brazil Tel: Fax: pietromainenti@terra.com.br