少突膠質(zhì)細胞瘤( oligodendroglioma,OG)于1929年首次被定義為一種膠質(zhì)瘤亞型,即腫瘤細胞形態(tài)學上類似于正常少突膠質(zhì)細胞,是分化好的、緩慢生長，但是呈彌漫性浸潤的大腦皮層或皮層下腫瘤。最有可能起源于少突膠質(zhì)細胞或不成熟的膠質(zhì)干細胞。2016年發(fā)布的CNS腫瘤分類標準首次推出了基于表型和基因型的聯(lián)合診斷標準,引入IDH突變和1p/9q雜合子聯(lián)合缺失狀態(tài)的分子分型,將少突膠質(zhì)細胞瘤分為少突膠質(zhì)細胞瘤,IDH突變型伴1p/19q雜合子聯(lián)合缺失和少突膠質(zhì)細胞瘤,NOS型。
Oligodendroglioma (OG) was first defined as a glioma subtype in 1929, that is, tumor cells are morphologically similar to normal oligodendroglioma cells, which are well-differentiated, slow-growing, but diffuse infiltrating cerebral cortex or subcortical tumors. The most likely source is oligodendrocytes or immature glial stem cells. The CNS tumor classification standard released in 2016 first introduced the combined diagnostic criteria based on phenotype and genotype, introducing molecular typing of IDH mutation and 1p/9q heterozygote deletion state, and classifying oligodendroglioma into oligodendroglioma,IDH mutation with 1p/19q heterozygote deletion and oligodendroglioma,NOS type.
少突膠質(zhì)細胞瘤占所有原發(fā)中樞神經(jīng)系統(tǒng)腫瘤的2%~5%,所有膠質(zhì)瘤的5%~20%。大約有半的腫瘤為WHOⅡ級,其余為間變型或混合型腫瘤。少突膠質(zhì)細胞瘤是一種成人的原發(fā)腫瘤,在兒童只占1%~5%。成人與兒童發(fā)病率比為8:1, 大部分發(fā)病年齡為35~55歲,發(fā)病高峰為40~45歲。男性比女性稍多見。50%~80%患者有癲癇,1/3有偏癱和感覺障礙,1/3有顱壓增高征象,還可出現(xiàn)精神癥狀等。少突膠質(zhì)細胞瘤進展緩慢,5年生存率為50%~75%,中位生存時間為10年。切除后局部復發(fā)比較常見,彌漫性腦脊液播散相對少見。不論組織學級別或基因狀態(tài),腫瘤大部分切除是首選治療方式,手術可獨立改善治療結果。1p/19等位基因聯(lián)合缺失的少突膠質(zhì)細胞瘤對化療非常敏感,有著良好的預后。
Oligodendrogliomas account for 2 to 5 percent of all primary CNS tumors and 5 to 20 percent of all gliomas. About half of the tumors for WHO Ⅱ level, between the rest for variant or mixed tumor. Oligodendroglioma (oligodendroglioma) is a primary tumor in adults and only occurs in 1 to 5 percent of children. The incidence ratio of adults to children was 8:1, most of the age of onset was 35-55 years old, and the peak of onset was 40-45 years old. Men are slightly more common than women. 50%~80% patients have epilepsy,1/3 have hemiplegia and sensory disorders,1/3 have signs of increased cranial pressure, and can also appear mental symptoms. Oligodendroglioma progresses slowly, with a 5-year survival rate of 50% to 75% and a median survival time of 10 years. Local recurrence is common after resection and diffuse CSF diffusion is relatively rare. Regardless of histological grade or genetic status, the majority of tumor resection is the preferred treatment, and surgery can independently improve the outcome. The 1p/19 allele associated with oligodendroglioma is very sensitive to chemotherapy and has a good prognosis.
少突膠質(zhì)細胞瘤在中樞神經(jīng)系統(tǒng)分布情況與神經(jīng)組織的容積相對應:額葉最大,少突膠質(zhì)細胞瘤最常見(38%),位于額葉者,預后稍好;顳葉居第二位,占所有少突膠質(zhì)細胞瘤的33%稍強;小腦少見;腦干罕見。盡管少突膠質(zhì)細胞瘤無包膜,具有浸潤性,但有膨脹性生長的趨向,不像星形細胞腫瘤那樣容易沿白質(zhì)通道擴散。單純的少突膠質(zhì)細胞瘤不常見,典型者常合并星形細胞增生,這種增生通常為良性,原發(fā)星形細胞的腫瘤內(nèi)含有少突膠質(zhì)增生區(qū)也是常見的。具有其他膠質(zhì)細胞類型特點的部分可以是反應性的或腫瘤性的。當腫瘤性少突細胞超過腫瘤的75%時,稱為少突膠質(zhì)細胞瘤,低于75%時,稱為混合性膠質(zhì)瘤。有一種腫瘤在組織學上與少突膠質(zhì)細胞瘤很類似,常見于大腦半球中線,起源于透明中隔或三腦室,常被誤診為少突膠質(zhì)細胞瘤,這種腫瘤稱為中樞神經(jīng)細胞瘤、屬成熟神經(jīng)元的腫瘤,而不是膠質(zhì)腫瘤。盡管絕大多數(shù)少突膠質(zhì)細胞瘤起源于腦白質(zhì),但部分明顯有向腦皮層擴散的趨勢,也可在硬膜下沿腦表面擴散,少見情況下,可以擴散到蛛網(wǎng)膜下腔。罕見的情況,也有人發(fā)現(xiàn)少突膠質(zhì)細胞瘤可以表現(xiàn)為軟腦膜腫瘤，盡管有人以圖像星形細胞瘤那樣建立少突膠質(zhì)細胞瘤的分級系統(tǒng),但惟一的共識是良性少突膠質(zhì)細胞瘤(新WHOⅡ級與惡性少突膠質(zhì)細胞瘤(新WHOⅢ級)之間有區(qū)別。少突膠質(zhì)細胞瘤的影像學表現(xiàn)與許多膠質(zhì)母細胞瘤相似,環(huán)形強化,壁厚不規(guī)則,瘤周廣泛水腫。偶爾浸潤性少突膠質(zhì)細胞瘤內(nèi)可出現(xiàn)鈣化,可能被認為是較良性的病變。有些病例,根據(jù)影像學表現(xiàn)和特點,少突膠質(zhì)細胞瘤無法與膠質(zhì)母細胞瘤鑒別。
The distribution of oligodendroglioma in the central frame of the nervous system corresponds to the volume of nerve tissue: the frontal lobe is the largest, oligodendroglioma is the most common (38%), located in the frontal lobe, the prognosis is slightly better; Temporal lobe was the second, accounting for 33% of all oligodendroglioma. Cerebellum rare; Brain stem is rare. Although oligodendrogliomas are nonenveloped and invasive, they tend to expand, unlike astrocytomas, which tend to spread through the white matter channels. Simple oligodendroglioma is uncommon, and typical cases are often associated with astrocytic hyperplasia, which is usually benign. It is also common for primary astrocyte tumors to contain areas of oligodendroglioma. The parts characteristic of other glial cell types may be reactive or neoplastic. When neoplastic oligodendroglioma exceeds 75% of the tumor, it is called oligodendroglioma, and below 75%, it is called mixed glioma. There is a tumor histologically similar to oligodendroglioma. It is common in the midline of the cerebral hemisphere and originates from the transparent septum or the third ventricle. It is often misdiagnosed as oligodendroglioma. Although the vast majority of oligodendrogliomas originate in the white matter of the brain, some of them have a clear tendency to spread to the cortex, or to the long side of the brain under the dura, or, in rare cases, to the subarachnoid space. Rare condition, also someone found oligodendrocytes tumor can be characterized by soft meningeal tumour, although someone with less image astrocytoma that established branch of gliomas grading system, but only the consensus of the tumor is benign oligodendrocytes (new WHO Ⅱ level and malignant oligodendrocytes (new WHO Ⅲ level) is there a difference between. The imaging findings of oligodendroglioma are similar to those of many glioblastomas, with annular enhancement, irregular wall thickness, and extensive edema around the tumor. Occasionally, calcification may occur in an invasive oligodendroglioma, which may be considered a benign lesion. In some cases, oligodendroglioma cannot be distinguished from glioblastoma according to imaging findings and characteristics
一般情況,不管組織學分級如何,少突膠質(zhì)細胞瘤呈不均質(zhì)的腫塊。除腫瘤的實質(zhì)部分以外,常有粘液或粘液樣物質(zhì)堆積區(qū)存在這種粘液“湖”，使腫瘤大體病理學和影像學上都表現(xiàn)為部分囊性,少突膠質(zhì)細胞瘤內(nèi)有腫瘤性的纖細的毛細血管網(wǎng),這些血管太小,血管造影時看不見,MR上也看不到血管流空，但可出現(xiàn)自發(fā)性出血,是少突膠質(zhì)細胞瘤的特點,可以出現(xiàn)不同大小和時期的出血,使腫瘤更加不均質(zhì)。
In general, oligodendroglioma is a heterogeneous mass, regardless of histologic grade. Except the essence of the tumor part, often have mucus or myxoid substance accumulation zone exists the mucus 'lake', tumor gross pathology and imaging expression is part of the cystic, oligodendrocytes tumor with tumor of slim capillary network, the blood vessels are too small, angiography was invisible, can't see blood flow on MR empty, but can be spontaneous bleeding, is the characteristic of oligodendrocytes tumor, can appear different size and time of bleeding, make tumor more heterogeneity.
鈣化是少突膠質(zhì)細胞瘤的特征,鈣化的發(fā)生率因影像技術的敏感性不同而不同,CT上鈣化高達91%,在組織學幾乎都能看到鈣化。軍事病理學院研究了82例少突膠質(zhì)細胞瘤,結果發(fā)現(xiàn)三分之二在CT片上可以見到直徑大于1cm的鈣化。組織學上,鈣化表現(xiàn)為腫瘤微血管內(nèi)的沉積或形成鈣球。鈣化可出現(xiàn)在腫瘤的任何部位,但以鄰近皮層灰質(zhì)尤為常見,呈現(xiàn)不規(guī)則腦回帶狀。腦回樣鈣化長期以來一直被認為是少突膠質(zhì)細胞瘤的特征,但是,隨著醫(yī)生的早期診斷這種腫瘤,鈣化率將可能下降,尤其是致密鈣化的發(fā)生率。
Calcification is characteristic of oligodendrogliomas. The incidence of calcification varies with the sensitivity of imaging techniques. Calcification is as high as 91% on CT and can be seen almost universally on histology. The military school of pathology studied 82 cases of oligodendrocytoma and found that two-thirds of them had calcification larger than 1cm in diameter on CT. Histologically, calcification is seen as deposition or formation of calcium globules in tumor microvessels. Calcification can occur anywhere in the tumor, but is particularly common in the adjacent cortical gray matter, which appears in irregular gyrus bands. Gyrus calcification has long been recognized as a characteristic of oligodendroglioma. However, with early diagnosis of the tumor, calcification rates may decline, especially with dense calcification.
與影像學常表現(xiàn)為均質(zhì)密度的低度星形細胞瘤相比,少突膠質(zhì)細胞瘤表現(xiàn)不均質(zhì),即使是良性的少突膠質(zhì)細胞瘤。在CT平掃,等低、鈣化常同時可見,偶有出血。低密度是粘液或粘液樣改變區(qū),占位效應與腫瘤大小相關,但也可能比預期的輕。水腫輕度或中度鈣化常為結節(jié)樣,也可為團塊狀,位于腫瘤的中心,也有鈣化呈腦回樣的報告.MR也能發(fā)現(xiàn)鈣化,但較困難,尤其是當鈣化呈細小的斑點狀或彌漫狀。盡管少突膠質(zhì)細胞瘤的鈣化比其他腫瘤更為常見,但少突膠質(zhì)細胞瘤相對罕見,所以,當CT平掃發(fā)現(xiàn)鈣化時,應該考慮其他的膠質(zhì)瘤。在討論有鈣化的實質(zhì)性腫瘤時,始終應該包括星形細胞腫瘤和室管膜瘤,還包括轉移性粘液腺癌和肉瘤。
In contrast to low-grade astrocytomas, which often appear homogeneous on imaging, oligodendrogliomas are heterogeneous, even in benign oligodendrogliomas. On plain CT scan, low grade and calcification are often seen at the same time, with occasional bleeding. The low density is the area of mucinous or myxoid changes, and the mass effect is related to tumor size, but may be less than expected. Mild to moderate edematous calcification is usually nodular, but can also be clumpy, located in the center of the tumor, and has been reported to be gyri like. Although oligodendroglioma calcification is more common than other tumors, oligodendroglioma is relatively rare, so other gliomas should be considered when calcification is found on plain CT scan. Solid tumors with calcification should always include astrocytomas and ependymomas, as well as metastatic mucinous adenocarcinoma and sarcomas.
少突膠質(zhì)細胞瘤的另外一個特征是浸蝕顱骨內(nèi)板，至少有三分之一的少突枝膠質(zhì)細胞瘤存在顱骨浸蝕,顱骨浸蝕有兩個特點:(1)沒有癥狀,緩慢生長;(2)腫瘤有明顯的向外生長的趨勢,通過腦灰質(zhì),達顱骨內(nèi)板。但這些特點并不是少突膠質(zhì)細胞瘤的特征,在緩慢生長的良性星形細胞瘤、神經(jīng)節(jié)膠質(zhì)瘤原發(fā)神經(jīng)外胚層腫瘤和腦膜瘤也可看到。
Another characteristic of oligodendroglioma is the erosion of the inner plate of the skull. At least one third of oligodendroglioma have skull erosion. (2) the tumor showed an obvious outward growth trend and reached the inner plate of the skull through the gray matter. However, these features are not characteristic of oligodendrogliomas, and can also be seen in slow-growing benign astrocytomas, neuroectodermal neoplasms of ganglioma origin, and meningiomas.
CT典型的少突膠質(zhì)細胞瘤為低密度、混雜等低密度或密度不均勻的腫塊,鈣化是其特點, 見于約70%的病例,可呈局限性點片狀、條索狀、不規(guī)則團塊狀、皮層腦回狀鈣化。腫瘤周邊多呈輕度水腫,部分病例可有囊變。緩慢生長的腫瘤, ?常常位置比較表淺,以皮層為基底。大量出血或瘤周水腫相對少見。腫瘤強化程度可從無到中度強化,多數(shù)呈輕度強化。
The typical oligodendroglioma in CT is a mass with low or uneven density, such as low density, mixed density, etc. Calcification is its characteristic. It can be seen in about 70% of cases, and it may present as localized patchy, wirelike, irregular mass and cortical gyrus calcification. Peripheral tumor showed mild edema, some cases may have cystic changes. Slow-growing tumors, often superficial in location, are subcortical. Massive bleeding or peri-neoplastic edema is relatively rare. The degree of tumor enhancement can be from none to moderate, and most of them are mild.
MR的T1WI為低或等信號腫塊,T2WI為不均勻高信號腫塊,主要是鈣化、囊變和極少量的不同時期出血的血液成分所造成的不均勻。約半數(shù)病例可見中度不均勻強化。典型病例常侵襲鄰近皮層,出血、壞死少見。T2- FLAIR能清晰顯示皮層受累情況。T2*WI或SWI,鈣化區(qū)可見“開花效應”。DWI擴散多不受限。MRS見Cho峰中等程度升高,NAA峰下降,脂峰/乳酸雙峰缺乏可將其與間變性少突膠質(zhì)細胞瘤鑒別開。少突膠質(zhì)細胞瘤常表現(xiàn)局灶性rCBV增高,是1p/19聯(lián)合缺失的少突膠質(zhì)細胞瘤的典型特點。少突膠質(zhì)細胞瘤rCBV升高并不表示高級別的病理特點。
MR T1WI is a low or isosignal mass, while T2WI is an uneven high signal mass, which is mainly caused by calcification, cystic degeneration and a very small amount of blood components bleeding at different periods. Moderate uneven enhancement was seen in about half of the cases. In typical cases, the adjacent cortex is often invaded, and hemorrhage and necrosis are rare. T2-flair can clearly show cortical involvement. T2*W or SW1, 'flowering effect' is seen in calcified areas. DWI diffusion is not limited. MRS found that Cho peak increased moderately,NAA peak decreased, and lipid peak/lactic acid bimodal deficiency could be distinguished from anaplastic oligodendroglioma. Oligodendroglioma often presents with focal increase in rCBV, which is a typical characteristic of oligodendroglioma with 1p/19 combined absence. Elevated rCBV in oligodendroglioma does not indicate a high-level pathological feature.
核醫(yī)學表現(xiàn)PET,FDG攝取值與正常灰質(zhì)相似,11C甲硫氨酸在少突膠質(zhì)細胞瘤與間變性少突膠質(zhì)細胞瘤攝取值明顯不同。
Nuclear medicine showed that the uptake value of PET and FDG was similar to that of normal gray matter, and the uptake value of 11C methionine in oligodendroglioma and anaplastic oligodendroglioma was significantly different.
鑒別診斷
間變性少突膠質(zhì)細胞瘤
不同分級的少突膠質(zhì)細胞瘤通過常規(guī)影像學是很難鑒別的,需要活檢才能鑒別。MRS、PWI或者PET有助于鑒別診斷。間變性少突膠質(zhì)細胞瘤常與少突膠質(zhì)細胞瘤有著相似的影像學表現(xiàn)。間變性少突膠質(zhì)細胞瘤瘤周水腫、出血、囊變和對比強化較常見,但也見于少突膠質(zhì)細胞瘤。有時與膠質(zhì)母細胞瘤環(huán)形強化相似的典型特點也可見到。
Oligodendrogliomas of different grades are difficult to identify by routine imaging and require biopsy. MRS, PWI or PET are helpful in differential diagnosis. Anaplastic oligodendroglioma and oligodendroglioma often have similar imaging findings. Anaplastic oligodendroglioma peritumor edema, hemorrhage, cystic degeneration and contrast enhancement are common, but also seen in oligodendroglioma. Sometimes characteristic features similar to annular enhancement of glioblastoma can be seen.
低級別彌漫型星形細胞瘤
彌漫浸潤性纖維型星形細胞瘤更常累及白質(zhì),且一般很少強化。與間變性少突膠質(zhì)細胞瘤或少突星形細胞瘤的鑒別很難,出血和壞死后者更常見些。鈣化少見, 常累及白質(zhì),皮層幾乎不受累,有時很難鑒別。?
Diffuse infiltrating fibrous astrocytomas are more frequently involved in white matter and rarely strengthen. Differentiation from anaplastic oligodendroglioma or oligodendroglioma is difficult and bleeding and necrosis are more common. Calcification is rare and often involves white matter. The cortex is rarely involved and is sometimes difficult to identify.
節(jié)細胞膠質(zhì)瘤
通常位于顳葉皮層,邊界更清晰,囊變加強化結節(jié),鈣化常見,兒童或青年人常見。
It is usually located in the temporal cortex with a clearer border, cystic enhancement nodules, calcification is common, and is common in children or young adults.
胚胎發(fā)育不良神經(jīng)上皮腫瘤
邊界銳利的皮層腫瘤,信號常不均勻,皂泡樣改變,且常伴皮層發(fā)育不良,強化方式多變,兒童或青年人常見。
Cortical neoplasms with sharp edges, often uneven signals, soap-like changes, and often associated with cortical dysplasia, often with variable enhancement patterns, are common in children or young adults.
多形性黃色瘤型星形細胞瘤
幕上皮層腫塊,腦膜尾征常見,常表現(xiàn)為囊加壁結節(jié),也可是完全實性,強化結節(jié)常毗鄰腦膜表面,兒童或年輕人常見。
Supratentorial masses and caudate meninges are common, often presenting as cystic and mural nodules, but also fully solid.
PS:少突膠質(zhì)細胞瘤生長緩慢,患者的生存期相對較長,來自瑞士的一項相關研究顯示少突膠質(zhì)細胞瘤患者的平均存活時間為11.6年,10年生存率為51%。但是手術切除腫瘤后局部復發(fā)較為常見,再次切除病理檢查仍然可以是分化較好的少突膠質(zhì)細胞瘤。
Oligodendroglioma grows slowly and patients have a relatively long survival period. A related study from Switzerland shows that the average survival time of oligodendroglioma patients is 11.6 years and the 10-year survival rate is 51%. However, local recurrence is common after surgical resection of the tumor, and reresection of the tumor can still be a well-differentiated oligodendroglioma by pathological examination.
