鑒別診斷
結(jié)節(jié)性硬化癥(TS)
結(jié)節(jié)性硬化癥是種神經(jīng)皮膚綜合征,由9q34.3(編碼錯構(gòu)瘤蛋白)和16p13.3(編碼 tuberin蛋白)染色體中基因突變所致。其中2/3為散發(fā)患者,其余為常染色體顯性遺傳,外顯率可不同。其典型的三聯(lián)征包括面部血管纖維瘤、智力低下和癲癇發(fā)作,但僅在約1/3的患者中出現(xiàn)。在中樞神經(jīng)系統(tǒng),TS可表現(xiàn)為皮質(zhì)或皮質(zhì)下結(jié)節(jié)、沿神經(jīng)元遷移方向呈放射狀分布的白質(zhì)病損、室管膜下結(jié)節(jié)和室管膜下巨細(xì)胞星形細(xì)胞瘤( SEGAs)。皮質(zhì)或皮質(zhì)下結(jié)節(jié)是由雜亂的神經(jīng)膠質(zhì)和異位的神經(jīng)元組成,表現(xiàn)為皮質(zhì)和皮質(zhì)下三角形異常信號,可見鈣化,有時呈現(xiàn)強(qiáng)化。室管膜下結(jié)節(jié)在T1和T2圖像上信號多變,但通?？梢姀?qiáng)化。當(dāng)有鈣化時,結(jié)節(jié)在MRI表現(xiàn)為低信號,而大多數(shù)鈣化發(fā)生在20歲之前。SEGAS為低級別腫瘤,在TS中的發(fā)生率為10%~15%,好發(fā)于孟氏孔,持續(xù)性生長,并可見強(qiáng)化。有無間隔生長是鑒別 SEGAS與室管膜下結(jié)節(jié)最好的標(biāo)志。治療通常傾向于腦脊液分流。與TS相關(guān)的常見病變很多,包括視網(wǎng)膜錯構(gòu)瘤、心臟橫紋肌瘤、腎囊腫和血管平滑肌脂肪瘤、肺淋巴管平滑肌瘤病、甲下纖維瘤和皮膚病損,如灰葉斑和鯊皮斑。
Tuberous sclerosis is a neurocutaneous syndrome caused by mutations within the tuberin chromosome 9q34.3(coding for hamartoma protein) and 16p13.3(coding for tuberin protein). Among them, 2/3 are sporadic patients, while the rest are autosomal dominant with different penetrance. The typical triad includes facial angiofibroma, mental retardation and seizures, but only appears in about a third of patients. In the central nervous system,TS may present as cortical or subcortical nodules, white matter lesions radially distributed along neuronal migration, subependymal nodules, and subependymal giant cell astrocytoma (SEGAs). Cortical or subcortical nodules are composed of a jumble of glial and heterotopic neurons that appear as abnormal triangular signals in the cortex and subcortical areas. Subependymal nodules show variable signals on T1 and T2 images, but are usually enhanced. Nodules show low signal on MRI when calcified, and most calcification occurs before age 20. SEGAS is a low-grade tumor, with an incidence rate of 10%~15% in TS. It often occurs in the foramen mengele, with continuous growth and visible enhancement. The presence or absence of septal growth is the best marker for distinguishing SEGAS from subependymal nodules. Treatment usually favors cerebrospinal fluid shunt. Common TS related lesions are numerous, including retinal hamartomas, cardiac rhabdomyomas, renal cysts, and angiomyolipomas, pulmonary lymphangiomyomatosis, subthyroid fibromas, and skin lesions such as gray leaf and shark skin.
灰質(zhì)異位
灰質(zhì)異位是由于正常神經(jīng)元從室管膜下區(qū)向皮質(zhì)遷移的過程被中斷所致,這種中斷可由胎兒在發(fā)育過程中的某些損傷引起?；屹|(zhì)異位可表現(xiàn)為結(jié)節(jié)狀或條帶狀。在MRI上,室管膜下的異位灰質(zhì)結(jié)節(jié)與大腦灰質(zhì)信號強(qiáng)度相同,無強(qiáng)化、無鈣化?；颊叱１憩F(xiàn)為癲癇發(fā)作和發(fā)育遲緩,而輕癥患者可無癥狀。
Ectopic gray matter is caused by the interruption of the migration of normal neurons from the subependymal region to the cortex. Heterotopic gray matter may appear nodular or banded. On MRI, the suboependymal heterotopic gray matter nodule had the same signal intensity as the gray matter in the brain, without enhancement or calcification. Patients often present with seizures and developmental delays, while mild cases may be asymptomatic.
TORCH感染
TORCH感染包括弓形蟲、風(fēng)疹、巨細(xì)胞病毒和單純性皰疹病毒感染。巨細(xì)胞病毒為最常見的 TORCH感染,可致室管膜下和腦實(shí)質(zhì)鈣化,在CT上與結(jié)節(jié)性硬化癥相似。 弓形蟲病也可致顱內(nèi)鈣化,但分布無規(guī)律,較少 分布于腦室周。該類患者通常可伴發(fā)小頭畸形和 神經(jīng)元遷移異常,如多小腦回和巨腦回?；颊咄?nbsp; 常表現(xiàn)為智力低下、癲癇和聽覺受損。
TORCH infections include toxoplasma, rubella, cytomegalovirus and herpes simplex. Cytomegalovirus is the most common TORCH infection, causing subependymal and parenchymal calcification similar to tuberous sclerosis on CT. Toxoplasmosis can also cause intracranial calcification, but its distribution is irregular and rarely distributed around the ventricle. Patients with this condition often have microcephaly and abnormal neuronal migration, such as multiple cerebellar gyrus and giant gyrus. Patients commonly present with mental retardation, epilepsy, and hearing impairment.
轉(zhuǎn)移性疾病
室管膜下轉(zhuǎn)移瘤可繼發(fā)于原發(fā)性中樞神經(jīng)系統(tǒng)病變,或顱外惡性腫瘤經(jīng)血行轉(zhuǎn)移。易于向室管膜下播散的原發(fā)性中樞神經(jīng)系統(tǒng)病變包括:多形性膠質(zhì)母細(xì)胞瘤、髓母細(xì)胞瘤、室管膜瘤、原發(fā)性中樞神經(jīng)系統(tǒng)淋巴瘤、生殖細(xì)胞腫瘤、松果體細(xì)胞瘤和脈絡(luò)叢腫瘤。多種 顱外腫瘤均可轉(zhuǎn)移至室管膜下和脈絡(luò)叢,尤其是乳腺癌。
Subependymal metastases may be secondary to primary central nervous system lesions, or extracranial malignancies may metastasized by blood. Primary central nervous system lesions that tend to spread subependymally include glioblastoma multiformis, medulloblastoma, ependymoma, primary central nervous system lymphoma, germ cell tumor, pineal cell tumor, and choroid plexus tumor. Many kinds of extracranial tumors can metastasize to the subependymal and choroid plexus, especially breast cancer.
