Primary meningeal melanoma with cerebrospinal fluid dissemination mimicking neurofibromatosis type 2

Melanoma meníngeo primário com disseminação liquórica mimetizando neurofibromatose tipo 2

A 38-year-old man admitted with headache, left paresis and bilateral sensorineural hearing loss. Neuroimaging showed a peripheral frontal tumor with hyperintensity on T1WI and bilateral internal auditory canal (IAC) lesions. (Figures 1, 2 and 3). The presence of hyperintensity on T1WI, without fat or hemorrhage should direct for lesions containing melanin¹. Resection of the frontal tumor diagnosed a primary malignant meningeal melanoma with cerebrospinal fluid dissemination once the patient has no melanocytic lesions outside the CNS. The melanocytic lesions ranges from melanocytoma to melanoma^2,3,4,5. Malignant melanoma should be included in the differential diagnosis of neoplastic CSF dissemination with bilateral IAC lesions mimicking schwannomas in NF2.

Figure 1
Non-contrast CT showed a right frontal hyperdense tumor (arrowhead).

Figure 2
MRI showed a frontal peripheral tumor with signal hyperintensity on T1WI (arrowhead) (A), signal hypointensity on T2WI (arrowhead) (B) and enhancement after contrast administration (arrowhead) (C), without hemorrhage on T2 gradient-echo (D).

Figure 3
FLAIR showed bilateral IAC lesions (arrowheads) (A), which increased over the following 30 days (arrowheads) (B) mimicking bilateral acoustic schwannoma in neurofibromatosis type 2.

References

• ¹
  Ginat DT, Meyers SP. Intracranial lesions with high signal intensity on T1-weighted MR images: differential diagnosis. Radiographics. 2012;32(2):499-516. http://dx.doi.org/10.1148/rg.322105761
  » https://doi.org/10.1148/rg.322105761
• ²
  Brat DJ, Giannini C, Scheithauer BW, Burger PC. Primary melanocytic neoplasms of the central nervous systems. Am J Surg Pathol. 1999;23(7):745-54.
• ³
  Roser F, Nakamura M, Brandis A, Hans V, Vorkapic P, Samii M. Transition from meningeal melanocytoma to primary cerebral melanoma: case report. J Neurosurg. 2004;101(3):528-31. http://dx.doi.org/10.3171/jns.2004.101.3.0528
  » https://doi.org/10.3171/jns.2004.101.3.0528
• ⁴
  Bydon A, Gutierrez JA, Mahmood A. Meningeal melanocytoma: an aggressive course for a benign tumor. J Neurooncol. 2003;64(3):259-63. http://dx.doi.org/10.1023/A:1025628802228
  » https://doi.org/10.1023/A:1025628802228
• ⁵
  Xie ZY, Hsieh KLC, Tsang YM, Cheung WK, Hsieh CH. Primary leptomeningeal melanoma. J Clin Neurosci. 2014;21(6):1051-2. http://dx.doi.org/10.1016/j.jocn.2013.08.018
  » https://doi.org/10.1016/j.jocn.2013.08.018

Publication Dates

• Publication in this collection
  July 2015

History

• Received
  26 Dec 2014
• Reviewed
  19 Feb 2015
• Accepted
  13 Mar 2015