Brain Tumors. Classification. Clinical features.
Classification- based on cellular origin, histology, genetic information and biologic behaviour of tumors. The classification of hypophyseal tumors is based on a functional principle and depends on their hormonal secretion and size.
Table 19.1 Histological classification of CNS tumor (WHO 1993), including cranial and spinal tumors
I. Tumors of neuroepithelial tissue
- 1. Astrocytic tumors – astrocytoma Grade I-II, malignant astrocytoma, glioblastoma, etc.;
- 2. Oligodendroglial tumors – oligodendroglioma, anaplastic oligodendroglioma;
- 3. Ependymal tumors – ependymoma, anaplastic ependymoma;
- 4. Mixed gliomas – oligoastrocytoma, oligoastroblastoma, etc.;
- 5. Choroid plexus tumors – papilloma, carcinoma;
- 6. Idiopathic neuroepithelial tumors – astroblastoma, polar spongyblastoma, gliomatosis;
- 7. Neuronal and mixed neuronal-glial tumors – gangliocytoma, ganglioglioma, central neurocytoma, etc.
- 8. Pineal parenchymal tumors – pineocytoma, pineoblastoma, mixed pineal tumors;
- 9. Embryonal tumors – medulloepithelioma, neuroblastoma, primitive neuroectodermal tumor (PNET), etc.
II. Tumors of cranial and paraspinal nerves
- Schwannoma (neurinoma, neurilemoma);
- Neurofibroma;
- Malignant Schwannoma (neurogenous sarcoma).
III. Tumors of the meninges
- Meningothelial tumors – meningioma, atypical, malignant, papillary;
- Mesenchymal non-meningothelial tumors:
- Benign – lipoma, fibroma, fibrous histiocytoma, osteochondroma, etc.,
- Malignant – haemangiopericytoma, chondrosarcoma, rhabdomyosarcoma;
- Primary melanocytic lesions – melanocytoma, malignant melanoma, diffuse melanosis.
IV. Lymphomas and haematopoietic tumors
- 1. Malignant lymphoma,
- 2. Plasmocytoma (multiple myeloma),
- 3. Granulocytic sarcoma,
- 4. Other.
Table 19.2 Classification of hypophyseal tumors
I. Non-secretory tumors
- Incidentaloma (incidentally found),
- Microadenoma (up to 10 mm in size),
- Mesoadenoma (11-20 mm),
- Macroadenoma (21-30 mm),
- Giant adenoma (larger than 31 mm).
II. Secretory tumors in sizes as group I. Depending on their hyper-secretion:
- 1. Prolactoma,
- 2. Adrenocorticotropinoma,
- 3. Somatotropinoma,
- 4. Thyreotropinoma,
- 5. Gonadotropinoma,
- 6. Combined.
V. Germ cell tumors
- 1. Germinoma,
- 2. Embryonal carcinoma,
- 3. Endodermal sinus tumor,
- 4. Choriocarcinom,
- 5. Mixed germ cell tumor,
- 6. Teratoma.
VI. Cysts and other neoplasms
- 1. Epidermoid cyst,
- 2. Dermoid cyst,
- 3. Colloidal cysts of III-rd ventricle,
- 4. Enterogenous cyst,
- 5. Plasma cell granuloma,
- 6. Neuroglial cyst,
- 7. Hypothalamic neural hamartoma,
- 8. Ratke cyst,
- 9. Granulocellular tumor (choristoma, pituicytoma).
VII. Tumors of the sellar region
- 1. Hypopheseal adenoma,
- 2. Hypopheseal carcinoma,
- 3. Craniopharyngioma.
VIII. Local extension of regional tumors of bone-cartilage-ligamental origin
- 1. Paraglioma,
- 2. Chordoma,
- 3. Chondroma,
- 4. Chondrosarcoma,
- 5. Osteoma,
- 6. Osteosarcoma,
- 7. Aneurysmal bone cyst,
- 8. Eosinophilic sarcoma,
- 9. Osteoid-osteoma/osteoblastoma,
- 10. Giant cell tumor,
- 11. Ewing sarcoma,
- 12. Other sarcomas.
IX. Metastasic tumors
- 1. Lung carcinoma,
- 2. Breast carcinoma,
- 3. Renal carcinoma,
- 4. Melanoma,
- 5. Gastrointestinal tract,
- 6. Other.