PE-206 - MANDIBULAR OSTEOSARCOMA: CASE REPORT. JULYANNA FILGUEIRAS GONÇALVES DE FARIAS, DANIELA PITA DE MELO, POLLIANNA MUNIZ ALVES, CASSIANO FRANCISCO WEEGE NONAKA, GUSTAVO PINA GODOY, PATRÍCIA MEIRA BENTO, DALIANA QUEIROGA DE CASTRO GOMES. UNI- VERSIDADE ESTADUAL DA PARAÍBA. Osteosarcoma is an aggressive malignancy that originates from primitive bone-forming mesenchymal cells and is charac- terized by osteoid matrix production. Osteosarcomas are rela- tively rare in the head and neck region. Approximately 5% of all osteosarcomas occur in the jaws. Woman, 40, had a chief complaint of strong pain and swelling in the mandible. Her medical history revealed breast cancer. Intraoral examination showed a lesion localized in the alveolar ridge between the third molar and the second premolar on the right side of the mandible. Panoramic radiograph and computed tomography revealed alteration in the trabecular bone with no well-defined bound- aries. Microscopically, intense cell proliferation and osteoid matrix deposition were observed. The diagnosis was consistent with osteosarcoma of metastatic breast cancer origin. Osteosar- comas of the jaws are rare entities, but can evolve rapidly and aggressively. Therefore knowledge of this lesion is vital to correctly diagnose and treat patients. PE-207 - MASTICATORY SPACE TUMOR: SCHWAN- NOMA WITH PSEUDOCYSTIC CHANGES. ANDREZA VERUSKA LIRA CORREIA, LUCIANO PADILHA DOS SANTOS, JUREMA FREIRE LISBOA DE CASTRO, FLÁVIA MARIA DE MORAES RAMOS-PEREZ, FELIPE PAIVA FONSECA, OSLEI PAES DE ALMEIDA, DANYEL ELIAS DA CRUZ PEREZ. FEDERAL UNIVERSITY OF PERNAM- BUCO; STATE UNIVERSITY OF CAMPINAS. Schwannomas are benign neoplasms that arise from Schwann cells. About 45% are located in the head and neck region. The presence of pseudocystic areas is uncommon. A case of schwannoma with pseudocystic areas was reported. Woman, 57, was referred for diagnosis of a swelling located in the oropharynx. Computed tomography revealed a well-defined hypodense image within the medial and lateral pterygoid muscles, measuring 4.0 cm in length. The lesion was excised under local anesthesia. Microscopically, there were hyper- cellular areas, with frequent nuclear palisading arrangements (Antoni A pattern), interspersed by less dense reticular areas. A large pseudocystic area was observed. Tumor cells were posi- tive for S-100 protein, suggesting the diagnosis of schwan- noma. In conclusion, schwannomas are well-circumscribed lesions that may contain pseudocystic areas but carry a good prognosis. PE-208 - MELANOMA IN THE ORAL CAVITY: CLINICAL CASE REPORT. VIVIANE DA SILVA SIQUEIRA, ANELISE RIBEIRO PEIXOTO ALENCAR, ANDRESA BORGES SOARES, JOSÉ FERREIRA DE MENEZES FILHO, FABRICIO PASSADOR SANTOS, RAFAEL STELINI. FAC- ULDADE DE ODONTOLOGIA SÃO LEOPOLDO MANDIC. Melanoma is rare in the oral cavity, representing 0.2% to 8% of all melanomas. Man, 73, complained of a swelling, present for the last 2 months, occurring after a dental extraction. The lesion had been increasing in size. Oral examination revealed an asymptomatic, exophytic, pigmented lesion, measuring 5 Â 5 cm, that was accompanied by an unpleasant odor. An incisional biopsy was performed. Histopathological examination revealed a fragment of mucosa lined by a stratified squamous parakeratinized epithelium, showing numerous irregularly distributed melanocytes, intense nuclear pleomor- phism, and hyperchromatism. Melanocytic positivity was demonstrated on immunohistochemical tests for HMB 45, S- 100, and Melan-A. The definitive diagnosis was melanoma. The patient was referred to a head and neck surgeon for treatment. After investigation, metastatic lung disease was diagnosed. The treatment of choice was palliative chemotherapy, but the patient died 2 months after diagnosis. PE-209 - MELANOTIC NEUROECTODERMAL TUMOR OF INFANCY: CASE REPORT WITH 1-YEAR FOLLOW- UP. JULIANA SEO, DANIEL ISAAC SENDYK, MARIA CRISTINA ZINDEL DEBONI, DANIEL MARTINS DE SOUZA, NORBERTO NOBUO SUGAYA, FABIO DAUMAS NUNES. FACULDADE DE ODONTOLOGIA DA UNI- VERSIDADE DE SÃO PAULO. Melanotic neuroectodermal tumor of infancy (MNTI) is a rare, fast-growing tumor with a high recurrence rate. Com- monly it develops in the anterior maxilla of children younger than age 1 year. Tumor origin is the neural crest. Girl, 2 months, had an increasingly large area of swelling on the left cheek. After tomography and biopsy, the diagnosis of MNTI was established. Histological examination indicated a remarkable combination of neural, melanocytic, and epithelial cell differ- entiation. One year after tumor excision, the child has had no recurrence. Since its first description, about 260 cases of this tumor have been reported. Early diagnosis minimized difficulties and risks during treatment and leads to an optimal outcome. Despite complete surgical excision, careful follow-up is rec- ommended. Maxillary functional orthopedic care and recon- struction may be necessary. PE-210 - MONOSTOTIC FIBROUS DYSPLASIA OF THE JAW: CASE REPORT WITH 10-YEAR FOLLOW-UP. SÍNTIQUE PRISCILA ALVES LUZ, JULIANA BASTOS FIGUEIRA, JÉSSICA OLIVEIRA MELO SILVA, LAIRA RENATA LEMOS SANTOS, VIVIANE ALMEIDA SARMENTO, PATRÍCIA LEITE RIBEIRO LAMBERTI. UNI- VERSIDADE FEDERAL DA BAHIA. Fibrous dysplasia is an idiopathic benign fibro-osseous lesion in which the normal bone is replaced by fibrous tissue. The monostotic form is found in 80% of diagnosed cases. Computed tomography is the most common imaging method performed to demonstrate the extent of the lesion in craniofacial bones. Sur- gical treatment includes reducing the injury to an acceptable margin, but future development is possible in 25% to 50% of cases. Woman, 34, was diagnosed with monostotic fibrous dysplasia of the jaw. She had been followed up for 10 years through clinical and imaging surveillance at the School of Dentistry, Federal University of Bahia. PE-211 - MUCOEPIDERMOID CARCINOMA IN A YOUNG PATIENT: CASE REPORT. ANA PAULA CANDIDO DOS SANTOS, ANA PATRÍCIA CARNEIRO GONÇALVES BEZERRA COELHO, RENATA MENDES MOURA, FABIO DAUMAS NUNES, DÉCIO DOS SANTOS PINTO JR., ANDREA LUSVARGHI WITZEL, CELSO AUGUSTO LEMOS. FACULDADE DE ODONTOLOGIA DA USP. ORAL AND MAXILLOFACIAL PATHOLOGY OOOO e172 Abstracts February 2014