title: Granular cell tumor mimicking a squamous cell carcinoma of the tongue: a case report.
abstract: BACKGROUND
  Granular cell tumor is a rare benign tumor that can present a pseudoepitheliomatous hyperplasia of the covering epithelium. This lesion is not encapsulated and can be characterized by a pseudo invasive growth pattern, represented by the tumoral cells that infiltrate between adjacent connective tissue elements. Diagnostic difficulties may arise because histopathological features of the pronounced pseudoepitheliomatous hyperplasia can be confused with a well-differentiated oral squamous cell carcinoma. The aim of this case report is to demonstrate the role of an immunohistochemical panel in the diagnosis of a granular cell tumor in the tongue with clinical and microscopic features resembling an oral squamous cell carcinoma.
  
  
  METHODS
  A 44-year-old white man with a history of heavy smoking and alcohol abuse presented an ulcerated nodular lesion in the dorsum of the tongue. The lesion was asymptomatic with fast growth. The clinical diagnosis was an oral squamous cell carcinoma. An incisional biopsy was performed and the ensuing histopathological analysis showed a pseudoepitheliomatous hyperplasia in the overlying epithelium mimicking the invasion of epithelial tumor cells into the connective tissue as in an oral squamous cell carcinoma. Immunohistochemical antibodies (S-100, vimentin, CD68, p53, Ki-67, E-cadherin, collagen IV and cytokeratin AE1/AE3) were used to characterize molecular aspects of the lesion. Strong staining of S-100 protein, CD68, vimentin, E-cadherin and low proliferative activity observed with Ki-67 expression confirmed the diagnosis of a granular cell tumor. The patient was submitted to surgical excision of the whole lesion. At a 12-month check-up, there was no evidence of recurrence.
  
  
  CONCLUSIONS
  This case report showed that the immunohistochemical profile was helpful in determining the clinical behavior of the tumor and establishing the final diagnosis with appropriate treatment.
authors.affiliation: Department of Oral Medicine (Oral Pathology), Dental School, Faculdade de Odontologia, Universidade Federal de Goiás, Praça Universitária, S/N, Setor Universitário, Goiânia-Goiás, CEP 74605-220, Brazil.
authors.forename: Jean Carlos Barbosa
authors.initials: JC
authors.lastname: Ferreira
authors.affiliation: Department of Oral Medicine (Oral Pathology), Dental School, Faculdade de Odontologia, Universidade Federal de Goiás, Praça Universitária, S/N, Setor Universitário, Goiânia-Goiás, CEP 74605-220, Brazil.
authors.forename: Angélica Ferreira
authors.initials: AF
authors.lastname: Oton-Leite
authors.affiliation: Department of Oral Medicine Dental, Association of Cancer of Combat of Goiás, Araujo Jorge Hospital, Goiânia, Brazil.
authors.forename: Rafaela
authors.initials: R
authors.lastname: Guidi
authors.affiliation: Department of Oral Medicine (Oral Pathology), Dental School, Faculdade de Odontologia, Universidade Federal de Goiás, Praça Universitária, S/N, Setor Universitário, Goiânia-Goiás, CEP 74605-220, Brazil. elismaur@ufg.br.
authors.forename: Elismauro Francisco
authors.initials: EF
authors.lastname: Mendonça
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000473:pathology; D024141:Collagen Type IV / Q000378:metabolism; D016586:Granular Cell Tumor / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D006965:Hyperplasia; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D009418:S100 Proteins / Q000378:metabolism; D014059:Tongue / Q000473:pathology; D014062:Tongue Neoplasms / Q000175:diagnosis* / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014746:Vimentin / Q000378:metabolism; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D015820:Cadherins; D024141:Collagen Type IV; D007633:Keratins; D019394:Ki-67 Antigen; D009418:S100 Proteins; D016159:Tumor Suppressor Protein p53; D014746:Vimentin; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C513384:CDH1 protein, human; C495901:TP53 protein, human
keywords: Case report; Diagnosis; Granular cell tumor; Immunohistochemistry; Squamous cell carcinoma