Pigmented Lesions of the Central Nervous System: Radiologic-Pathologic Correlation

Abstract

Pigmented lesions of the central nervous system (CNS) are a diverse group of entities that run the gamut from benign to malignant. These lesions may be well circumscribed or diffuse, and their imaging appearances are influenced by the degree of melanin content as well as the presence or absence of hemorrhage. Pigmented lesions include primary melanocytic lesions of the CNS and metastatic melanoma, as well as other CNS neoplasms that may undergo melanization, including schwannoma, medulloblastoma, and some gliomas. Primary melanocytic lesions of the CNS arise from melanocytes located within the leptomeninges, and this group includes diffuse melanocytosis and meningeal melanomatosis (seen in neurocutaneous melanosis), melanocytoma, and malignant melanoma. Primary melanin-containing lesions of the CNS must be differentiated from metastatic melanoma because these lesions require different patient workup and therapy. Absence of a known primary malignant melanoma helps in the differential diagnosis, but an occult primary lesion outside the CNS must be sought and excluded. Pigmented lesions of the CNS are uncommon, and knowledge of their imaging characteristics and pathologic features is essential for their identification.

MR Imaging Findings of the Intraspinal Meningeal Melanocytoma: Correlation with Histopathologic Findings

“…5,9 The clinical signs and symptoms depend on its location and may present as myelopathy and seizures. 10,12 The symptoms of our patients were nonspecific, mainly caused by mass compression.…”

“…6,7,10,11 The annual incidence of MM is estimated to be 1 case per 10 million people, and women are vulnerable. 10 Our hospital has an extremely large collection area for patients from Guangdong province and 4 neighboring provinces. The orthopedics center in our hospital is very famous and is also a referral center for spinal tumors.…”

“…The average age in our series is 49.2 years, which is consistent with that in other reports. 10,11 Approximate 59 cases of intraspinal MM have been reported. 5 Nineteen cases were founded in the intramedullary location, while others were located in the extramedullary area.…”

Primary spinal melanoma of extramedullary origin: a report of three cases and systematic review of the literature

“…Higher melanin concentration was associated with higher signal intensities on T1W images and lower signal intensities on T2W images. 15 In CNS melanoma, this typical sign was observed in less than half of the patients; 16 however, in our review of PSM of extramedullary origin, these typical changes were observed in 95% (20/21) of patients. Therefore, when an intraspinal extramedullary tumor shows hyperintense T1W and hypointense T2W signaling, melanoma should be suspected.…”

“…Spinal schwannoma or meningioma lacks the characteristic signals (hyperintensity on T1W and hypointensity on T2W) on MRI examination, even in pigmented schwannoma or meningioma. 15 Spinal extramedullary hematoma usually presents with intense, 'knife-like' pain at the location of the hemorrhage ('coup de poignard') and subsequently progressive paralysis below the affected spinal level. These clinical features are different from those of primary melanoma.…”