【病例】椎旁神经纤维瘤(NF 1)1例MR

History: A 22-year-old woman undergoing spinal MR imaging. History is withheld.

病史:22岁女性行脊柱MR扫描,病史不明。

T2-weighted turbo inversion-recovery magnitude (TIRM) images are shown below. T2WI压脂图像如下所示。

【病例】椎旁神经纤维瘤(NF 1)1例MR

【病例】椎旁神经纤维瘤(NF 1)1例MR

Findings

MR images demonstrate multiple foraminal and paraspinal masses that involve all the neuroforamina in the cervical, thoracic, and lumbar segments. These masses have low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. There is intraspinal involvement resulting in cord compression in the upper cervical spine. There are no areas of abnormal enhancement following contrast administration (not shown).

影像表现:

MRI示多个椎间孔和椎旁肿物,累及颈椎、胸椎和腰椎中的所有神经孔。 这些肿物在T1WI上呈低信号,在T2WI上呈高信号。 椎管内受累导致上颈椎脊髓受压。 注射造影剂后未见明显异常强化(图像未显示)。

Differential diagnosis

  • Schwannoma
  • Paraspinal neurofibromas in spinal NF1
  • Malignant peripheral nerve sheath tumor
  • Paraganglioma
  • Neuroblastoma
  • Chordoma
  • Metastatic disease
  • Paraspinal abscess
  • Lymphadenopathy
  • Extramedullary hematopoiesis

鉴别诊断:

  • 神经鞘瘤
  • 脊柱NF1之椎旁神经纤维瘤
  • 恶性外周神经鞘瘤
  • 副神经节瘤
  • 神经母细胞瘤
  • 脊索瘤
  • 转移性疾病
  • 椎旁脓肿
  • 淋巴结肿大
  • 髓外造血

Diagnosis: Paraspinal neurofibromas in spinal NF1

最后诊断:椎旁神经纤维瘤(NF 1)

Key points

Paraspinal neurofibromas in spinal neurofibromatosis type 1 (NF1)

脊柱神经纤维瘤病1型之椎旁神经纤维瘤

Pathophysiology

  • Peripheral neurofibromas are benign peripheral nerve sheath tumors comprised of Schwann cells, fibroblasts, mast cells, and perineural cells.
  • Neurofibromas can arise anywhere along the peripheral nerve from the dorsal root ganglion to the terminal nerve branches.
  • Paraspinal neurofibromas usually develop from a relatively large nerve, and it is usually confined to the nerve, rather than spreading into the dermis and soft tissues. They tend to be large and multiple.
  • They have unpredictable rates and patterns of growth, but they usually grow during puberty or pregnancy.
  • The clinical subtype spinal NF1 is associated with a unique phenotype and genotype that are characterized by massive neoplastic enlargement of most of the spinal roots and multiple paraspinal tumors. Dermal manifestations are less common.
  • Spinal manifestations of NF1 include acute kyphoscoliosis at the cervicothoracic junction and vertebral body anomalies, dural ectasia and lateral meningocele, intramedullary tumors (particularly glial tumors), and paraspinal neurofibromas or plexiform neurofibromas.
  • With spinal NF1, neurofibromas and plexiform neurofibromas affect almost all the spinal roots.
  • The most common spinal tumors associated with NF1 are benign neurofibromas.

病理生理学:

  • 外周神经纤维瘤是良性的外周神经鞘肿瘤,由许旺细胞、成纤维细胞、肥大细胞和神经周细胞组成。
  • 神经纤维瘤可在从背根神经节到终末神经分支的周围神经的任何地方出现。
  • 脊柱旁神经纤维瘤通常起源于相对较大的神经,通常局限于神经,而不是扩散到真皮和软组织中。它们往往是大而多。
  • 它们具有不可预测的发育率和增长模式,但通常在青春期或怀孕期间增长。
  • 临床亚型脊柱NF1与独特的表型和基因型相关,其特征在于大部分脊髓根部瘤样增大和多发椎旁肿瘤。皮肤表现少见。
  • NF1的脊柱表现包括:颈胸交界处的急性脊柱侧后凸和椎体异常,硬膜扩张和侧脑膜膨出,髓内肿瘤(特别是神经胶质瘤)以及椎旁神经纤维瘤或丛状神经纤维瘤。
  • 在脊柱NF1,神经纤维瘤和丛状神经纤维瘤几乎影响所有的脊髓根部。
  • 与NF1相关的最常见的脊柱肿瘤是良性神经纤维瘤。

Epidemiology

  • NF1 is the most common neurocutaneous disorder, affecting approximately 1 in 3,300 infants.
  • It is an autosomal dominant disorder with variable penetrance.
  • The incidence rate of spinal tumors in patients with NF1 is 36%.

流行病学

  • NF1是最常见的神经皮肤疾病,婴儿中发病率约为3,300分之一。
  • 它是一种具有可变外显率的常染色体显性疾病。
  • NF1患者脊柱肿瘤的发生率为36%。

Clinical presentation

  • In patients with paraspinal neurofibromas, clinical manifestations depend on the location and extent of the disease with nerve root and spinal cord compression or even vertebral destruction, leading to serious long-term morbidity and death.
  • Small paraspinal neurofibromas are usually asymptomatic.

临床表现

  • 在脊柱旁神经纤维瘤患者中,临床表现取决于神经根和脊髓受压甚至脊椎破坏的位置和程度,可导致严重的长期病死率。
  • 小的椎旁神经纤维瘤通常无症状。

【病例】椎旁神经纤维瘤(NF 1)1例MR

Imaging features

Radiographs: Dystrophic scoliosis is common in patients with paraspinal neurofibromas.

CT:

  • Paraspinal neurofibromas appear as low-attenuation masses along the nerve root of the cervical, thoracic, or lumbar spine. Can appear at any level of the spine.
  • Generally, they do not enhance after the administration of intravenous contrast.

MRI:

  • They appear as masses with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images.
  • They have variable gadolinium enhancement.
  • The target sign describes the low-signal intensity center.
  • Malignancy is suspected if there is significant interval increase in size, ill-defined margins, lack of target sign, and heterogeneity with areas of necrosis.
  • Intramedullary tumors are uncommon but are gliomas (astrocytomas) in 95% of the cases.

PET: May distinguish benign from malignant neurofibromas in NF1 based on uptake.

影像表现

X线平片:营养不良性脊柱侧凸在脊柱旁神经纤维瘤患者中很常见。

CT:

  • 椎神经纤维瘤表现为沿颈椎,胸椎或腰椎神经根的低密度肿块,可出现在脊椎的任何水平;
  • 一般而言,增强扫描无明显强化

MRI:

  • 表现为T1低信号和T2高信号;
  • 增强后强化程度不同;
  • “靶征”表现为中心低信号;
  • 如果存在明显椎间孔增大,病变边界不清,缺乏靶征和因坏死而不均质,则要怀疑为恶性;
  • 髓内肿瘤并不常见,但95%的病例是胶质瘤(星形细胞瘤)。

PET:可根据摄取情况区分NF1中的良性和恶性神经纤维瘤。

Treatment and prognosis

  • Complications include overgrowth, nerve compression, and malignancy. Risk of developing a malignant peripheral nerve sheath tumor is approximately 10%.
  • Treatment for enlarging or symptomatic paraspinal neurofibromas is surgical resection; however, it is challenging given the infiltrative nature of the lesion, location, and recurrence.
  • Some biologically targeted therapies under investigation include receptor associated (RAS) targeted therapy, mechanistic target of rapamycin (mTOR) inhibitors, interferon, or multikinase inhibitors.

治疗和预后

  • 并发症包括过度生长,神经压迫和恶变。发生恶性周围神经鞘瘤的风险约为10%。
  • 增大或有症状的椎旁神经纤维瘤的治疗是手术切除,然而考虑到病变的浸润性、位置和复发,这具有一定挑战性。
  • 一些正在研究的生物靶向治疗包括受体相关(RAS)靶向治疗,雷帕霉素(mTOR)抑制剂的机械靶点,干扰素或多激酶抑制剂

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