Overview of meningeal carcinomatosis
Carcinomatous meningoencephalitis (meningeal carcinomatosis) is an intracranial metastatic lesion that causes symptoms similar to those associated with meningitis due to extensive metastatic infiltration of malignant tumor cells into the meninges and subarachnoid space. Strictly speaking, it should be collectively referred to as tumor meningeal metastasis. Its incidence is low, clinical manifestations are atypical, and lack of specificity. Carcinomatous meningitis is a serious complication of cancer, with a high rate of disability and death and a very poor prognosis.
Etiology
It is mainly caused by diffuse subarachnoid infiltration of tumors in other parts of the body through hematogenous spread, local direct invasion or contamination of soft meninges by tumor cells during intracranial surgery. Clinically, cancers that easily complicate carcinomatous meningitis include lung cancer, leukemia, lymphoma, gastric cancer, breast cancer, malignant melanoma and so on.
Symptoms
The manifestations are atypical and lack specificity. And often present symptom-sign separation, that is, the symptoms are very obvious, but no obvious positive signs. In the early stage of the disease, only intractable headache can be manifested, but nausea and vomiting may not be obvious. As the disease progresses, signs of meningeal irritation, such as nuchal rigidity, may gradually appear. It may also be accompanied by impaired consciousness or psychiatric symptoms. If the nerve roots of the spinal cord are invaded, the symptoms may be reflected in the region of innervation. If the nerve roots of the spinal cord are invaded, pain may be manifested, and some patients may also have weakness of the limbs.
Examination
Cranial CT is usually devoid of positive findings. Magnetic resonance enhancement scan sometimes reveals extensive meningeal enhancement, which is informative for the diagnosis of the disease. EEG is moderately diffuse and abnormal. Cerebrospinal fluid (CSF) examination is an important means of diagnosing the disease. On the basis of the appropriate symptoms, cerebrospinal fluid examination tends to show increased pressure, increased white blood cell counts, increased proteins, decreased sugar content, and decreased chlorides. The diagnosis is confirmed when tumor cells are found in cerebrospinal fluid cytology. What is seen presents the characteristics of primary tumor, with obviously enlarged cytosol, larger than normal cytoplasmic ratio, deep nuclear staining, strongly basophilic cytoplasm, mostly blue, and visible vacuoles; the nucleus is round or oval, mostly one nucleus, and a few of them are multinucleated, and some of them can be seen with nucleolus and filamentous schizophrenia. Adenocarcinoma cells can also be seen as imprinted cells, and the cytoplasm of malignant melanoma cells contains melanin granules.
Diagnosis
It is easy to be misdiagnosed as central nervous system infection, subarachnoid hemorrhage, epilepsy and cerebral infarction. Prompt cytologic examination of cerebrospinal fluid is helpful for diagnosis. If the diagnosis cannot be confirmed, lumbar puncture examination should be repeated several times, and the diagnosis can be confirmed if typical cancer cells can be found in the cerebrospinal fluid. Finding the primary tumor helps diagnosis.
Treatment
Currently, there is no satisfactory treatment, and the main treatment is chemotherapy regimen for the type of primary tumor. Methotrexate and/or cytarabine intrathecal injections are also adopted for treatment, but the efficacy is mostly seen in leukemia, lymphoma and other tumor types that are sensitive to the above two drugs. Radiotherapy is generally not an option due to the diffuse nature of the lesions in the vast majority of patients.
Prognosis
This clinical situation is an end-stage manifestation of the tumor, and therefore the prognosis is extremely poor.