title: Primary Intracranial Epidermoid Carcinoma with Diffuse Leptomeningeal Carcinomatosis: Report of Two Cases.
abstract: BACKGROUND
  Malignant degeneration of epidermoid cyst (EC) with accompanying leptomeningeal carcinomatosis (LC) at presentation is extremely rare. We add two cases to the literature, including the first case of primary brainstem involvement with simultaneous diffuse LC, and discuss clinical and radiological cues to differentiate benign and malignant epidermoid tumors for early diagnosis.
  
  
  METHODS
  The first patient in this report was a 54-year-old woman with recurrent aseptic meningitis and hydrocephalus. Imaging revealed a prepontine and parapontine extra-axial EC with an intra-axial brainstem ring-enhancing cystic lesion, diffuse leptomeningeal enhancement, and intradural extramedullary nodular deposits throughout the spine. Surgical decompression of the cysts confirmed the diagnosis of invasive primary squamous cell carcinoma of the brainstem and benign epidermoid tumor of the cerebellopontine cistern. The second patient was a 37-year-old woman with extensive left-sided cranial neuropathies. Imaging revealed prepontine and parapontine enhancing and nonenhancing deposits along multiple cranial nerves and diffuse leptomeningeal nodular enhancement in the thoracolumbar spine. A biopsy confirmed the diagnosis of infiltrative, poorly differentiated carcinoma adjacent to a benign EC. Both patients underwent systemic screening to rule out metastatic disease.
  
  
  CONCLUSIONS
  These cases illustrate that a high index of clinical suspicion is necessary for early diagnosis of disseminated disease in cases of recurrent episodes of aseptic meningitis. In cases of primary benign EC, aggressive resection should be attempted to reduce the risk of malignant degeneration. A separate biopsy specimen from the enhancing portion of the tumor is used to rule out an underlying coexisting malignancy. Multimodal management carries the best prognosis for primary intracranial squamous cell carcinoma with LC.
authors.affiliation: Department of Neurological Surgery, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Amol
authors.initials: A
authors.lastname: Raheja
authors.affiliation: Department of Neurological Surgery, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Ilyas M
authors.initials: IM
authors.lastname: Eli
authors.affiliation: Department of Neurological Surgery, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Christian A
authors.initials: CA
authors.lastname: Bowers
authors.affiliation: Department of Pathology, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Cheryl Ann
authors.initials: CA
authors.lastname: Palmer
authors.affiliation: Department of Neurological Surgery, University of Utah, Salt Lake City, Utah, USA. Electronic address: neuropub@hsc.utah.edu.
authors.forename: William T
authors.initials: WT
authors.lastname: Couldwell
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000628:therapy; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000628:therapy; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D055756:Meningeal Carcinomatosis / Q000175:diagnosis* / Q000628:therapy; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis* / Q000628:therapy
keywords: Brainstem; Epidermoid cyst; Intracranial; Leptomeningeal carcinomatosis; Malignant transformation; Primary; Squamous cell carcinoma