title: Papillary squamous cell carcinoma presenting on the gingiva.
abstract: BACKGROUND
  Papillary squamous cell carcinoma (PSCC) is a rare variant of squamous cell carcinoma. PSCC can occur as either an in situ or invasive tumor. The sites of occurrence in order of the most to least prevalent are the larynx, oropharynx, and nasopharynx. We present an unusual case of PSCC occurring on the gingiva.
  
  
  METHODS
  A 72-year-old white female presented with a chief complaint of tooth mobility in the right posterior mandible. Clinical examination revealed a Miller's Class 2 mobility of tooth #28 along with an erythematous, papillary appearance of the lingual gingiva on teeth #27, #28, and #29. Her dental history revealed treatment of tooth #28 with locally delivered antibiotics. Her medical history revealed a diagnosis of breast cancer 8 years prior to examination that was treated with partial mastectomy and radiation therapy. An initial differential clinical diagnosis of verrucous carcinoma or metastatic carcinoma was made.
  
  
  RESULTS
  Surgical therapy included extraction of tooth #28 and an excisional biopsy of the lesion on the lingual gingiva. Microscopic evaluation of the gingival specimen revealed a neoplastic papillary proliferation of the surface epithelium with a thick layer of parakeratin, deep parakeratin-lined crypts, and a thickened spinous cell layer along with islands and strands of malignant epithelium. The microscopic appearance of the lesion was characteristic for PSSC. The patient's tumor was removed via a block resection that included teeth #27 through #31 and a radical neck dissection.
  
  
  CONCLUSIONS
  This is a case report of PSCC occurring on the gingiva. This report demonstrates that, even though oral cancers involving the periodontium are a relatively rare occurrence, periodontists cannot be complacent about the diagnosis of periodontal bone loss. It also highlights the importance of utilizing a histopathologic examination to confirm the clinical diagnosis for any suspicious lesion.
authors.affiliation: Department of Periodontics, Indiana University School of Dentistry, Indianapolis, Indiana 46202, USA.
authors.forename: Saba M
authors.initials: SM
authors.lastname: Khan
authors.forename: Michael K
authors.initials: MK
authors.lastname: Gossweiler
authors.forename: Susan L
authors.initials: SL
authors.lastname: Zunt
authors.forename: Michael D
authors.initials: MD
authors.lastname: Edwards
authors.forename: Steven B
authors.initials: SB
authors.lastname: Blanchard
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D005887:Gingival Neoplasms / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008334:Mandible / Q000601:surgery; D037981:Neck Dissection; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D016609:Neoplasms, Second Primary / Q000175:diagnosis* / Q000601:surgery; D010518:Periodontitis / Q000175:diagnosis