title: Metastatic rectal adenocarcinoma in the mandibular gingiva: a case report.
abstract: BACKGROUND
  Oral metastatic tumor from a rectal adenocarcinoma is very uncommon. The primary site is usually assumed based on the past clinical history. In the case of oral metastatic tumors, they commonly have a poor prognosis because often they have already spread to other sites.
  
  
  METHODS
  We present the case of a 64-year-old male patient with secondary metastasis to the mandibular gingiva via lung metastasis after the surgical resection of a primary rectal adenocarcinoma. The gingival lesion grossly appeared as a swollen mass, making mastication difficult. The patient received palliative radiotherapy for the mandibular mass lesion. However, tumor reduction was accompanied by the development of pneumonia and deterioration of the patient's cachexia. Thus, the radiotherapy was discontinued but the patient died 2 months postradiotherapy. In the long term after its primary resection, the rectal adenocarcinoma was deduced to have finally metastasized to the oral region.
  
  
  CONCLUSIONS
  In this case, we consider a distant secondary metastasis to the oral region from a rectal malignancy. In such cases, careful clinical and pathologic evaluations are necessary, with careful consideration of the inclusion of palliative treatment in the therapeutic management.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo, Ami-machi, Inashiki-gun, Ibaraki, 300-0395, Japan. masa1114@tokyo-med.ac.jp.|Department of Oral and Maxillofacial Surgery, Tokyo Medical University Hospital, 6-7-1 Nishishinjuku, Shinjuku, Tokyo, 160-0023, Japan. masa1114@tokyo-med.ac.jp.
authors.forename: Masato
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Department of Oral and Maxillofacial Surgery, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo, Ami-machi, Inashiki-gun, Ibaraki, 300-0395, Japan.|Department of Oral and Maxillofacial Surgery, Tokyo Medical University Hospital, 6-7-1 Nishishinjuku, Shinjuku, Tokyo, 160-0023, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Tada
authors.affiliation: Department of Oral and Maxillofacial Surgery, Tokyo Medical University Hospital, 6-7-1 Nishishinjuku, Shinjuku, Tokyo, 160-0023, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Satomi
authors.affiliation: Department of Oral and Maxillofacial Surgery, Tokyo Medical University Hospital, 6-7-1 Nishishinjuku, Shinjuku, Tokyo, 160-0023, Japan.
authors.forename: Daichi
authors.initials: D
authors.lastname: Chikazu
authors.affiliation: Department of Radiation Oncology, Faculty of Medicine, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Mizumoto
authors.affiliation: Department of Radiation Oncology, Faculty of Medicine, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sakurai
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000601:surgery; D001706:Biopsy; D002100:Cachexia / Q000209:etiology; D017809:Fatal Outcome; D005682:Gadolinium / Q000008:administration & dosage; D005881:Gingiva / Q000000981:diagnostic imaging / Q000473:pathology*; D005887:Gingival Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy / Q000556:secondary*; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy / Q000556:secondary* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000473:pathology; D008339:Mandibular Neoplasms / Q000556:secondary; D008875:Middle Aged; D010166:Palliative Care / Q000379:methods*; D011013:Pneumonectomy; D011379:Prognosis; D017564:Radiation Pneumonitis / Q000209:etiology; D011878:Radiotherapy / Q000009:adverse effects; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery; D013125:Spinal Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy / Q000556:secondary; D014057:Tomography, X-Ray Computed; D028761:Withholding Treatment
chemical_list: D005682:Gadolinium
keywords: Gingiva; Metastasis; Rectal adenocarcinoma