Extensive central nervous system involvement in Merkel cell carcinoma: a case report and review of the literature.
BACKGROUND
Merkel cell carcinoma is a rare malignant cutaneous neoplasm that is locally invasive and frequently metastasizes to lymph nodes, liver, lungs, bone and brain. The incidence of Merkel cell carcinoma has increased in the past three decades.


METHODS
A 65-year-old Caucasian man presented with a sudden onset of severe headache and a three-month history of balance disturbance. Magnetic resonance imaging revealed a large meningeal metastasis. The radiologic workup showed retroperitoneal and inguinal lymph node metastases. Biopsy of the inguinal lymph nodes showed metastases of Merkel cell carcinoma. Biopsy from three different suspected skin lesions revealed no Merkel cell carcinoma, and the primary site of Merkel cell carcinoma remained unknown. Leptomeningeal metastases, new axillary lymph node metastases, and intraspinal (epidural and intradural) metastases were detected within six, seven and eight months, respectively, from the start of symptoms despite treating the intracranial metastasis with gamma knife and the abdominal metastases with surgical dissection and external radiotherapy. This indicates the aggressive nature of the disease.


CONCLUSIONS
To the best of our knowledge, this is the first report in the literature of an intracranial meningeal metastasis of Merkel cell carcinoma treated with gamma knife and of intraspinal intradural metastases of Merkel cell carcinoma. Despite good initial response to radiotherapy, recurrence and occurrence of new metastases are common in Merkel cell carcinoma.
Faculty of Medicine, Lund University, Diagnostic Centre for Imaging and Functional Medicine, Skåne University Hospital, 205 02 Malmö, Sweden. Kasim.Abul-Kasim@med.lu.se.
Kasim
K
Abul-Kasim
Kristina
K
Söderström
Lennart
L
Hallsten
J Neurosurg. 2011 Mar;114(3):769-79
20524829
Am J Otolaryngol. 2005 May-Jun;26(3):210-3
15858780
Magn Reson Imaging. 2004 Nov;22(9):1340
15607111
J BUON. 2010 Apr-Jun;15(2):274-80
20658721
Eur Spine J. 2008 Sep;17 Suppl 2:S267-70
18057968
Neurol Med Chir (Tokyo). 2002 Feb;42(2):78-80
11944594
J Neurooncol. 2010 Apr;97(2):295-9
19806319
Neurosurg Rev. 1999;22(1):54-7
10348209
Am Surg. 1997 May;63(5):450-4
9128236
J Clin Neurosci. 2010 Aug;17(8):1069-71
20488712
Ann Otol Rhinol Laryngol. 2004 Sep;113(9):683-7
15453522
J Surg Oncol. 2005 Jan 1;89(1):1-4
15611998
Magn Reson Imaging. 2000 Oct;18(8):1039-42
11121710
Cancer. 1986 Jan 1;57(1):178-82
3940617
J Neurooncol. 2010 Jun;98(2):163-7
20411300
Arch Dermatol. 1972 Jan;105(1):107-10
5009611
J Comput Tomogr. 1987 Jul;11(3):291-3
3608556