Kwok Henry, Hameed Meera, Hwang Sinchun
Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, US.
Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, US.
Skeletal Radiol. 2023 Feb;52(2):205-214. doi: 10.1007/s00256-022-04171-w. Epub 2022 Sep 7.
To evaluate MR features and clinical course of malignant melanotic nerve sheath tumor (MMNST), previously known as melanotic schwannoma and considered indolent and rarely metastasizing.
This IRB-approved retrospective study searched 31 patients (20 male: 11 female, mean age 48; range 15-76) with histologically confirmed MMNST in a single tertiary cancer center over 22 years. Pre-treatment MR was available in 12 patients and evaluated by two radiologists in consensus regarding lesion location, size, morphology, signal characteristics, contrast enhancement, local invasion, and presence of classic signs of peripheral nerve sheath tumors. Clinical outcomes, including local recurrence, metastasis, and survival, were examined in 12 patients for whom follow-up was available.
The spine was the most frequent site (13/31) among all identified cases. In 12 cases with MR, lesions were well-circumscribed in 11/12 cases, with a mean size of 4.5 cm (2.3-13.0 cm). Ten of 12 cases showed T1 hyperintensity. In 5/9 spinal MRI, tumor involved multiple levels. All lesions showed contrast enhancement, and local bone invasion in > 50%. A dumb-bell shape was common to all spinal lesions. Classical signs of nerve sheath tumors were uncommon. Among 12 patients with a mean follow-up of 4.8 years (range 1.3-10.2 years), six were disease-free, while two had recurrence or metastases, and four had died of metastases.
MMNST usually presents as a T1 hyperintense enhancing dumb-bell shaped mass in the spine. Multi-level involvement and bone invasion are common. MMNST is clinically aggressive with high rates of metastases and death.
评估恶性黑色素性神经鞘瘤（MMNST）的磁共振成像（MR）特征及临床病程，该肿瘤既往称为黑色素性神经鞘瘤，曾被认为生长缓慢且很少发生转移。
本项经机构审查委员会（IRB）批准的回顾性研究，在一家三级癌症中心对22年间组织学确诊的31例MMNST患者（男性20例，女性11例，平均年龄48岁；范围15 - 76岁）进行了检索。12例患者有治疗前的MR图像，由两名放射科医生共同评估病变的位置、大小、形态、信号特征、对比增强、局部侵犯以及周围神经鞘瘤的典型征象。对12例有随访资料的患者检查了临床结局，包括局部复发、转移和生存情况。
在所有确诊病例中，脊柱是最常见的部位（13/31）。12例有MR图像的病例中，11/12例病变边界清晰，平均大小为4.5厘米（2.3 - 13.0厘米）。12例中有10例T1加权像呈高信号。在9例脊柱MRI检查中，5例肿瘤累及多个节段。所有病变均有对比增强，超过50%有局部骨质侵犯。所有脊柱病变均常见哑铃形。神经鞘瘤的典型征象不常见。12例患者平均随访4.8年（范围1.3 - 10.2年），6例无疾病复发，2例有复发或转移，4例死于转移。
MMNST通常表现为脊柱内T1加权像呈高信号、有对比增强的哑铃形肿块。多节段受累和骨质侵犯常见。MMNST临床侵袭性强，转移率和死亡率高。
