Melanocytic lesions of the central nervous system: a case series

ABSTRACT

Background: Melanocytic lesions of the central nervous system (CNS) are an infrequent, broad and diverse group of entities, both benign and malignant, found in all age groups, with imaging findings ranging from well-circumscribed focal lesions to diffuse leptomeningeal involvement. On MRI, they are usually distinguished by a high signal on T1WI sequences, given the paramagnetic effect of melanin, thus making it difficult to differentiate among them. Objective: To describe the imaging and epidemiological characteristics of a retrospective series of CNS melanocytic lesions. Methods: MR images of 23 patients with CNS melanocytic lesions diagnosed between January 2012 and June 2018 were analyzed. Results: Most patients were female (14/23; 61%), with a median age of 47 years (range: 3 weeks to 72 years). The primary melanocytic lesions accounted for 8/19 cases (42.1%), which included neurocutaneous melanosis, meningeal melanocytomas and primary malignant melanomas. Secondary melanocytic lesions (metastatic) accounted for 10/19 cases (52.6%). There was one case of a tumor with secondary melanization, from a melanocytic neuroectodermal tumor of infancy. There were also four cases of primary ocular melanomas. The most frequent findings were the cerebral location, high T1WI signal and marked contrast-enhancement. Conclusions: The present review describes the wide variety of melanocytic lesions that could affect the CNS, emphasizing the MRI characteristics. Knowledge of the imaging, clinical and epidemiological characteristics of CNS melanocytic lesions is essential for their correct interpretation, given the significant overlap between lesion features and the variable prognosis.

RESUMEN

Antecedentes: Las lesiones melanocíticas del sistema nervioso central (SNC) corresponden a un grupo infrecuente, amplio y diverso de entidades, tanto benignas como malignas, encontradas en todos los grupos etarios, con hallazgos imagenológicos que van desde lesiones focales bien circunscritas hasta un compromiso leptomeníngeo difuso. A la RM se distinguen por la alta señal en la secuencia T1WI, dado el efecto paramagnético de la melanina, haciendo difícil la diferenciación entre ellas. Objetivo: Describir las características epidemiológicas y de de una serie retrospectiva de lesiones melanocíticas del SNC. Métodos: Revisión de imágenes de RM de 23 pacientes con lesiones melanocíticas del SNC diagnosticadas entre enero de 2012 y junio de 2018. Resultados: La mayoría de los pacientes fueron mujeres (14/23; 61%), con edades comprendidas entre las 3 semanas de vida hasta los 72 años. Las lesiones melanocíticas primarias representaron 8/19 (42,1%), incluyendo: melanosis neurocutáneas, melanocitomas meníngeos y melanomas malignos primarios. Las lesiones melanocíticas secundarias (metastásicas) representaron 10/19 casos (52,6%). Hubo un caso de tumor con melanización secundaria (tumor neuroectodermico melanocítico de la infancia). Se incluyeron cuatro casos de melanomas oculares primarios. Los hallazgos más frecuentes fueron la localización cerebral, el aumento de señal T1 y el acentuado realce con el gadolinio. Conclusiones: Se describe la amplia variedad de lesiones melanocíticas encontradas en el SNC, enfatizando sus características a la RM. El conocimiento de sus características imagenológicas, clínicas y epidemiológicas es fundamental para su correcta interpretación, dado la notable superposición entre las presentaciones de las lesiones y lo variable de sus pronósticos.

Keywords:

Central Nervous System Diseases - Melanosis - Neurocutaneous Syndromes - Magnetic Resonance Imaging - Neoplasm Metastasis

Palabras clave:

Enfermedades del Sistema Nervioso Central - Melanosis - Síndromes Neurocutáneos - Imagen por Resonancia Magnética - Metástasis de la Neoplasia

Authors’ contributions:

JVP: writing original draft, review & editing, supervision; AVT: writing, conceptualization, supervision; JPCQ: writing, conceptualization, supervision; FMS: review, supervision; JME: review & editing, supervision.

Publication History

Received: 02 March 2021

Accepted: 17 June 2021

Article published online:
30 January 2023

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