title: Atypical presentation of oral basaloid squamous cell carcinoma.
abstract: OBJECTIVE
  The purpose of this report is to present the clinical and histological features of a basaloid squamous cell carcinoma (BSCC) occurring in the retromolar trigone of a 59-year-old man and to relate its immunohistochemical characteristics.
  
  
  BACKGROUND
  BSCC is an aggressive distinct variant of squamous cell carcinoma (SCC) requiring recognition as a separate entity from SCC due to its peculiar behavior.
  
  
  METHODS
  A clinical examination revealed a 12x07x07 mm nodular mass with a rubbery consistency, defined borders, covered by reddish mucosa and an absence of bleeding upon palpation. Histologically, nests and cords of closely packed, moderately pleomorphic basaloid cells with nuclear palisading along the periphery of the neoplastic nests surrounded by a fibrous stroma were found.
  
  
  CONCLUSIONS
  Since this tumor can mimic other neoplasms such as adenoid cystic carcinoma, neuroendocrine carcinoma, and basal cell adenocarcinoma, histological features are essential to differentiate between them. Furthermore, immunohistochemical testing can provide valuable diagnostic information that can have a profound impact on treatment options and the prognosis.
  
  
  CONCLUSIONS
  BSCC needs to be differentiated from other neoplasms as early as possible because of its adverse prognosis. Clinicians are advised to conduct a mucosal evaluation during oral examinations and take a thorough medical history which could ultimately save the life of a patient.
authors.affiliation: Department of Oral Pathology, School of Dentistry, University of São Paulo, São Paulo, Brazil. mscamp@usp.br
authors.forename: Marcia Sampaio
authors.initials: MS
authors.lastname: Campos
authors.forename: Filipe
authors.initials: F
authors.lastname: Modolo
authors.forename: José Simão
authors.initials: JS
authors.lastname: de Oliveira
authors.forename: Decio S
authors.initials: DS
authors.lastname: Pinto-Júnior
authors.forename: Suzana C O M
authors.initials: SC
authors.lastname: de Sousa
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis; D003528:Carcinoma, Adenoid Cystic / Q000175:diagnosis; D018278:Carcinoma, Neuroendocrine / Q000175:diagnosis; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000473:pathology; D002295:Carcinoma, Transitional Cell / Q000175:diagnosis* / Q000473:pathology; D002467:Cell Nucleus / Q000648:ultrastructure; D003937:Diagnosis, Differential; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D019394:Ki-67 Antigen / Q000032:analysis; D007797:Laminin / Q000032:analysis; D008297:Male; D008875:Middle Aged; D008938:Mitosis; D009062:Mouth Neoplasms / Q000175:diagnosis* / Q000473:pathology; D009336:Necrosis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
chemical_list: D019394:Ki-67 Antigen; D007797:Laminin; D016159:Tumor Suppressor Protein p53; D007633:Keratins