Childhood tumor

Many types of TM can be detected in intracranial GCT patients, but there are mainly four types that are widely used in clinical practice: ① AFP, the main serum protein of human fetuses, is 1-10ng/ml in normal children, with a molecular weight of 65 thousand daltons (kDa); ② β- HCG is secreted by normal placental syncytiotrophoblast cells with a molecular weight of 45kDa; ③ The surface glycoprotein of PLAP cells, with a molecular weight of 68kDa, can be expressed normally in the syncytiotrophoblast cells (STGC) of the placenta CEA, also known as carcinoembryonic antigen, is a glycoprotein with a molecular weight of 318kDa. The pathological subtypes of GCT vary, and the types and levels of TM expression vary. 1. The CT plain scan of germ cell tumors shows circular irregular or butterfly shaped, uniform or slightly high-density, with or without calcification and small cystic changes; Enhancement can show smaller cystic changes, mostly manifested as moderate to significantly uniform enhancement, with a few uneven enhancements. There is dot shaped calcification around the lesion. The simultaneous detection of tumor lesions in the pineal and sellar regions is beneficial for the diagnosis of germ cell tumors. MRI scans often show equal or slightly longer T1 and slightly longer T2 signals, with occasional T1 mixed with high signal bleeding lesions. Uniform reinforcement, clear boundaries, with only a few showing moderate or uneven reinforcement. The basal ganglia region of GE has its unique imaging characteristics: the tumor volume is large, but the occupying effect is not significant, the edema near the tumor is mild, and it is often accompanied by atrophy of the cerebral cortex in the ipsilateral lateral fissure area. During enhanced scanning, it appears as irregular wreath like enhancement or spot like enhancement. Nagata believes that the mechanism leading to cortical atrophy in the lateral fissure area is Wslerian degeneration: tumor infiltration and destruction of white matter in the brain, especially nerve fibers in the inner capsule. According to reports, using immunohistochemical methods, 75 to 100% of GE patients were PLAP positive. if β- If HCG<50IU/L, AFP>20ng/ml, and PLAP positive, it should be considered as a pure germ cell tumor. 2. Teratoma and malignant teratoma show nodular, lobulated, or irregular morphology on CT plain scan. Uneven density, usually manifested as solid, cystic, calcified, and ossified coexisting, especially in polycystic cases. The enhancement is manifested as significant but extremely uneven enhancement of the solid part, and the cyst wall may exhibit multiple circular enhancement. Although it is difficult to distinguish between benign and malignant teratomas on CT, generally speaking, the latter has a larger solid part, relatively less cystic changes, calcification, and fat components, and is commonly accompanied by peritumoral edema. Both MRT1 and T2 showed extremely mixed signals, with obvious enhancement in both the solid and cystic walls, clear boundaries, and more commonly seen in nodular and lobular shapes. If there is a flowing oil signal in the brain ventricle, it can be diagnosed with this disease. If accompanied by peritumoral edema, it indicates malignant teratoma. TMCEA can be slightly or moderately elevated. Patients with immature teratoma and mixed GCT containing this component showed a significant increase in AFP. 3. Endodermal sinus tumor CT plain scan shows irregular solid tumors with low density, high density, or mixed density, without cystic changes, accompanied by varying degrees of peritumoral edema, and some cases may have mixed teratoma components. MRI tumor T1WI shows equal or low signal intensity, while T2WI shows uneven high signal intensity, with significant uneven enhancement after drug injection. TM plays a very important role in the diagnosis and treatment of this type of tumor, sometimes even more reliable than pathology, as incomplete pathological sampling can lead to missed diagnosis. Patients with endodermal sinus tumors or mixed germ cell tumors containing endodermal sinus tumor components have AFP positivity, and can be diagnosed if serum AFP>1000ng/ml. CEA can increase slightly or moderately. 4. Embryonic cancer shows high density on CT plain scan, sometimes with visible tumor calcification. MRIT1WI shows equal signal, T2WI shows equal or high signal, with obvious enhancement after injection, and some cases have cystic changes. TM50% Embryonic Cancer Patient Serum β- Elevated HCG; CEA can be slightly or moderately elevated; AFP can be mildly or moderately elevated in patients with embryonic cancer and mixed intracranial germ cell tumors containing this component. 5. Chorionic epithelial carcinoma is different from other intracranial germ cell tumors. The imaging manifestations and TM expression of chorionic epithelial carcinoma have their own characteristics: CT plain scan shows slightly high-density shadows, which can have both calcification and bleeding. MRI plain scan T1WI or slightly higher or mixed signals are caused by subacute bleeding at different stages within the tumor, with obvious tumor enhancement. TM100% serum from patients with chorionic epithelial carcinoma β- Elevated HCG, β- Elevated HCG levels can indicate that the tumor is choriocarcinoma or mixed germ cell tumors containing choriocarcinoma components, such as β- HCG>1000mlU/ml is almost certain to be choriocarcinoma or mixed germ cell tumors containing choriocarcinoma components. CEA can increase slightly or moderately. Except for benign teratomas, intracranial germ cell tumors are prone to cerebrospinal fluid implantation and dissemination. In some patients, detached tumor cells can be found in the cerebrospinal fluid, which has significant diagnostic significance, but the clinical detection rate is not high. The diagnosis of intracranial germ cell tumors mainly occurs in midline areas such as the suprasellar region, basal ganglia region, and pineal gland region. Different pathological subtypes of tumors have their own characteristics in terms of age, gender ratio, site distribution, disease duration, clinical manifestations, and imaging features. Based on this, a preliminary diagnosis can be made, but it is not yet sufficient to distinguish between GCT and other tumors or between GE and NGGCTs. The final diagnosis still depends on tumor marker (TM) level detection, cerebrospinal fluid cytology examination, and/or in vivo tissue examination.