title: Carcinoma cuniculatum mimicking leukoplakia of the mandibular gingiva.
abstract: Carcinoma cuniculatum (CC) is a rare variant of low-grade squamous cell carcinoma (SCC), and occurrence in the oral cavity is quite unusual. CC has a papillomatous keratinized surface like verrucous carcinoma, but CC has a propensity for aggressive local invasion, especially into the bone. Therefore, CC can be quite difficult to remove surgically. A 68-year-old man presented with a case of CC mimicking verrucous leukoplakia in the mandibular gingiva. Repeated biopsies showed no malignancy. Local resection was performed, and histological examination revealed the presence of well-differentiated SCC. Additional hemi-mandibulectomy was performed and the final histological diagnosis was CC. Local recurrence was detected at the 14-month follow-up examination. Chemotherapy with docetaxel was not effective, and he died of aspiration pneumonia. CC of the oral cavity is a rare entity and the diagnosis is hard to establish. Misdiagnosis could result in inadequate removal and local recurrence. Complete resection with a safety margin is essential because of the tendency for local invasion.
authors.affiliation: Department of Otolaryngology, National Sendai Medical Center, 2-8-8 Miyagino, Miyagino-ku, Sendai, Miyagi 983-8520, Japan. j_suzuki1212@orl.med.tohoku.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Suzuki
authors.forename: Sho
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Watanabe
authors.forename: Kaoru
authors.initials: K
authors.lastname: Takahashi
authors.forename: Hajime
authors.initials: H
authors.lastname: Usubuchi
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D003937:Diagnosis, Differential; D006801:Humans; D007972:Leukoplakia, Oral / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008334:Mandible / Q000473:pathology*; D009062:Mouth Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D009364:Neoplasm Recurrence, Local