Intramedullary melanotic schwannoma of the conus medullaris: a case report

Abstract

Study design: A case of a very rare type of schwannoma is reported. It is the sixth reported case of intramedullary melanotic schwannoma and the only one localized in the conus. Methods: A 56-year-old woman was treated in this department for a C5-C6 spondylodiscitis. After 6 months her arms showed a rapid recovery, but her incomplete flaccid paraplegia remained stable. Magnetic resonance imaging (MRI) with gadolinium enhancement of the lumbar tract revealed an intramedullary lesion at the level of Th12-L1. During surgery, an intramedullary, poorly vascularized, dark gray lesion was detected and was totally removed. One year after surgery, no recurrence was encountered and the patient showed significant improvement. Conclusion: It had previously been hypothesized that intramedullary melanotic schwannomas originate from the rostral components of the neural tube. This case presented a different localization with respect to the previously described cases, all localized in the cervical or high thoracic tracts, and thus uncertainties are raised about the previous hypotheses. Nevertheless, it is agreed that total surgical removal is the best treatment.

Melanotic schwannoma of the lumbar spine: a case report and literature review

“…Regarding their recurrence potential, we found in the literature rates ranging from 18.2% 6 to 24%, 7 being almost always related to incomplete resections. [1][2][3][4]7 Moreover, studies have shown that among patients who were followed for more than five years, only slightly more than half were disease free at the end of follow-up, suggesting that long term monitoring is necessary to assess tumor recurrence and risk of metastasis. 10 …”

“…[1][2][3][4][5][6][7][8] We found a mean age of about 50 years old, the masculine gender being present in slightly more than half of the cases reviewed. The thoracic level was the most affected, with prevalence of extramedullary location (eight of the eleven reported cases), as well as in our patient, in which we found the development of extramedullary and intradural injury.…”

“…The positivity for HMB-45 and Melan-A is an unexpected finding, given that these antibodies are considered relatively specific for the diagnosis of malignant melanoma. 10 Reports indicate that in 10% of cases melanocytic schwannomas are malignant tumors, 1,4,7 suggesting that the presence of melanocytic Schwann cells could predispose to malignant transformation in some patients. Regarding their recurrence potential, we found in the literature rates ranging from 18.2% 6 to 24%, 7 being almost always related to incomplete resections.…”

“…10 Reports indicate that in 10% of cases melanocytic schwannomas are malignant tumors, 1,4,7 suggesting that the presence of melanocytic Schwann cells could predispose to malignant transformation in some patients. Regarding their recurrence potential, we found in the literature rates ranging from 18.2% 6 to 24%, 7 being almost always related to incomplete resections. [1][2][3][4]7 Moreover, studies have shown that among patients who were followed for more than five years, only slightly more than half were disease free at the end of follow-up, suggesting that long term monitoring is necessary to assess tumor recurrence and risk of metastasis.…”

Intramedullary Melanotic Schwannoma

“…This is only the 7th reported case to our knowledge describing this tumor (Table 1). 2 , 5–9 Various explanations for this tumor's unusual location in the central nervous system have been put forth (Table 2). 6,8 , 10–13 …”