Intramedullary spinal cord metastasis of malignant melanoma:Two cases with rim signs in contrast‑enhanced magnetic resonance imaging: A case report

Abstract

Spinal cord metastasis of malignant melanoma is mostly caused by the invasion of the spinal cord by malignant melanoma. However, direct metastasis in the spinal cord is rare and difficult to diagnose accurately. A few diagnostically valuable findings of intramedullary spinal cord metastases (ISCMs) have been published. However, a highly specific finding of ISCMs of all carcinomas is the 'rim sign', which signifies the enhancement of the edge-dominant effect of the lesion in contrast-enhanced MRI. The objective of this case series was to examine the ratio of ISCMs of malignant melanoma with an indication of rim signs in contrast-enhanced MRI. The present report describes two cases of ISCMs of malignant melanoma in which the rim sign in contrast-enhanced MRI was useful for diagnosis.

Intramedullary Spinal Cord Metastasis as Initial Presentation of Malignant Melanoma: A Unique Case Report and Role of Contrast vs Non-contrast MRI in Its Diagnosis

“…Rim sign indicate a more intense thin rim with peripheral enhancement than other tumor areas and flame signs indicate flame-shaped enhancements at the edge of the lesion. Depending upon the variable degree of tumour melanin content, the signal characteristics on MRI are biased [8,[10][11][12]. Flame and rim sign, two unique characteristics of ISCM on contrast, are present in a much lower percentage in ISCM of other cancers [8].…”

“…Depending upon the variable degree of tumour melanin content, the signal characteristics on MRI are biased [8,[10][11][12]. Flame and rim sign, two unique characteristics of ISCM on contrast, are present in a much lower percentage in ISCM of other cancers [8]. Considering the above facts, it is diagnostically challenging to detect ISCM of melanoma.…”

“…In the literature, ISCM of malignant melanoma is described as a small percentage of the ISCMs of all cancer types; thus, it is sometimes not reported in detail. Twenty-seven cases of ISCM of malignant melanoma have been reported so far in a recent study [ 8 ]. On review of literature, we could not find any reported case with ISCM secondary to malignant melanoma as initial presentation.…”

“…It has been suggested that MRI is the most effective imaging technique for revealing spinal cord melanoma. According to most authors, the MRI pattern of spinal cord melanoma includes signal hyperintensity on T1-weighted images and signal iso- or hypo-intensity on T2-weighted images [ 8 ]. With injection of an appropriate contrast medium, there should be a moderate enhancement of the lesion [ 9 ].…”

Spinal oncologic paraparesis: Analysis of neurological and surgical outcomes in patients with intramedullary, extramedullary, and extradural tumors

“…tumors of the central nervous system. In contrast, extradural metastases with potential spinal cord compression (MSCC) possess the lion share of spinal tumors (60%) ( 4 ) and affect about 5% of all cancer patients ( 5 ), with intramedullary metastases known to be rare ( 6 , 7 ).…”