title: Non-metastatic squamous cell carcinoma within a Rathke's cleft cyst.
abstract: BACKGROUND
  Primary intracranial and sellar squamous cell carcinoma is an extremely rare entity, usually caused by malignant transformation of epidermoid cysts, or very rarely other non-malignant epithelial cysts. Malignant transformation of a Rathke's cleft cyst has never been described.
  
  
  METHODS
  We present a 49-year-old male patient who presented with a 3-month history of progressive frontotemporal headaches. Imaging revealed a 1.2 cm cystic pituitary mass consistent with a hemorrhagic Rathke's cleft cyst. The patient underwent trans-sphenoidal resection of the pituitary cyst, and pathologic analysis revealed a squamous cell carcinoma lining a Rathke's cleft cyst. Extensive imaging and otorhinolaryngologic evaluation revealed no primary source for metastasis.
  
  
  CONCLUSIONS
  We feel this represents the first case of a patient with a pituitary lesion in which presentation and MRI imaging were consistent with Rathke's cleft cyst, yet histology revealed squamous cell carcinoma in situ.
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA. brian.o'neill@joslin.harvard.edu.|Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, 1 Joslin Pl, Rm 605, Boston, MA, 02215, USA. brian.o'neill@joslin.harvard.edu.
authors.forename: Brian T
authors.initials: BT
authors.lastname: O'Neill
authors.affiliation: University of Massachusetts School of Medicine, Worcester, MA, USA.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Segkos
authors.affiliation: Department of Neurosurgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Ekkehard M
authors.initials: EM
authors.lastname: Kasper
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Johanna A
authors.initials: JA
authors.lastname: Pallotta
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000601:surgery; D020863:Central Nervous System Cysts / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D010900:Pituitary Diseases / Q000473:pathology / Q000601:surgery; D010902:Pituitary Gland / Q000473:pathology / Q000601:surgery; D010911:Pituitary Neoplasms / Q000175:diagnosis* / Q000601:surgery
keywords: Cancer; Epithelial cyst; Pituitary; Rathke’s cleft cyst; Squamous cell carcinoma