title: Salivary duct carcinoma metastatic to eyelid and orbit-a case report.
abstract: BACKGROUND
  Salivary duct carcinoma is a rare, extremely aggressive malignant tumor, demonstrating invasive growth with early regional and distant metastasis. We describe a case of parotid gland salivary duct carcinoma metastatic to the eyelid and orbit, as confirmed by immunohistochemical analysis. To the best of our knowledge, this is the first such case reported in the literature.
  
  
  METHODS
  A 43-year-old male had left lower eyelid and left inferior fornix/anterior orbital masses. The patient underwent left lower eyelid and anterior orbital biopsies for histopathological evaluation. Immunohistochemical analysis for markers like androgen receptors, gross cystic disease fluid protein-15, cytokeratins, HER-2/neu, epithelial membrane antigen, S-100 proteins, progesterone receptors, and estrogen receptors were performed to establish diagnosis.
  
  
  RESULTS
  Specimens from the eyelid and orbit revealed lobules of tumor cells exhibiting solid, micopapillary, and glandular appearance with central necrosis-comedo patterns. The tumor cells showed immunohistochemical reactivity to androgen receptor proteins, pankeratin, HER-2/neu and epithelial membrane antigen. Focal reactivity to gross cystic disease fluid protein-15 was also present. Immunoreactivity to S-100 proteins, progesterone receptors, and estrogen receptors were negative. Diagnosis was metastatic paratoid duct carcinoma to the left lower eyelid and left inferior orbit.
  
  
  CONCLUSIONS
  Although metastatic SDC of the eyelid and orbit is a rare phenomenon, the possibility of this extremely aggressive entity should be included in the differential diagnosis when dealing with a patient with an eyelid and/or orbital tumor.
authors.affiliation: Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.
authors.forename: Jignesh G
authors.initials: JG
authors.lastname: Parikh
authors.forename: Michael A
authors.initials: MA
authors.lastname: Burnstine
authors.forename: Satoru
authors.initials: S
authors.lastname: Kase
authors.forename: Narsing A
authors.initials: NA
authors.lastname: Rao
mesh_terms: D000231:Adenocarcinoma, Papillary / Q000737:chemistry / Q000556:secondary* / Q000601:surgery; D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D001707:Biopsy, Needle; D005142:Eyelid Neoplasms / Q000737:chemistry / Q000556:secondary* / Q000601:surgery; D006801:Humans; D008297:Male; D009918:Orbital Neoplasms / Q000737:chemistry / Q000556:secondary* / Q000601:surgery; D010307:Parotid Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery
chemical_list: D014408:Biomarkers, Tumor