title: Signet ring carcinoma parotid gland: a case report.
abstract: BACKGROUND
  Signet ring adenocarcinoma is a recently characterized entity occurring in the minor salivary glands. All reported cases have occurred in minor salivary gland. Pure signet ring adenocarcinoma of a major salivary gland has not been reported in the literature.
  
  
  METHODS
  A 38-year-old woman presented with a mass in the parotid region. Microscopy showed signet ring cells positive for mucicarmine. Immunohistochemistry showed cytokeratin and focal smooth muscle actin (SMA) positivity; an exhaustive search for primary elsewhere did not reveal any suspicious focus.
  
  
  RESULTS
  A diagnosis of low-grade signet ring adenocarcinoma of the parotid gland was made. On 6-month follow-up the patient was alive and well.
  
  
  CONCLUSIONS
  The present case highlights a rare occurrence of this tumor in the parotid gland, which until now was labeled as a tumor exclusive to minor salivary glands. Thus this entity should be kept as a differential while investigating mucinous tumors of parotid.
authors.affiliation: Department of Pathology, Maulana Azad Medical College and Lok Nayak Hospital, Bahadur Shah Zafar Marg, New Delhi, India. meetamamc@gmail.com
authors.forename: Meeta
authors.initials: M
authors.lastname: Singh
authors.forename: Nita
authors.initials: N
authors.lastname: Khurana
authors.forename: Rachna
authors.initials: R
authors.lastname: Wadhwa
authors.forename: Achal
authors.initials: A
authors.lastname: Gulati
mesh_terms: D000328:Adult; D001707:Biopsy, Needle; D018279:Carcinoma, Signet Ring Cell / Q000473:pathology* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D010307:Parotid Neoplasms / Q000473:pathology* / Q000601:surgery*; D035583:Rare Diseases; D018570:Risk Assessment; D016896:Treatment Outcome