Page 634 - Concise Pathology for Exam Preparation ( PDFDrive )

23 The Central Nervous System 619

Pathology:
• Intense oedema and vascular congestion

• Widespread neuronal degeneration and inflammation (most severe in the mid-brain

and floor of the fourth ventricle)

• Negri bodies (round to oval eosinophilic intracytoplasmic inclusion bodies in

pyramidal neurons of the hippocampus and Purkinje cells of the cerebellum)
7.
HIV–associated viral encephalitis
Clinical features:
• Insidious, presents with mental slowing and mood disturbances.
• Motor abnormalities, ataxia and seizures may also be seen.
�

Pathology:
May manifest with either of the following:
• Aseptic (lymphocytic) meningitis
• Myelin loss
• Meningoencephalitis
Q. Write briefly on Lyme disease.
Ans. It is caused by Borrelia burgdorferi (a spirochaete).
Clinical features:
• Aseptic meningitis
• Facial nerve palsy
• Encephalopathy
• Polyneuropathies
Pathology:
Focal proliferation of microglia with scattered organisms.
Q. Classify neoplastic lesions of CNS. Enumerate their salient

clinicopathological features.
Ans. Neoplastic lesions of CNS and their Clinicopathological Features:
Incidence
• Intracranial tumours are more common than intraspinal.
• More than half are primary; rest are metastatic.
• Constitute 20% of all cancers of childhood.
• In children, majority occur in the posterior fossa, whereas in adults, the cerebral hemi-
spheres are most commonly involved.

Unique Features of CNS Tumours:
• Benign and malignant tumours are difficult to differentiate based on morphology alone.
• Anatomic site can have lethal consequences irrespective of morphology.
• Accessibility to surgical resection is limited.
• Pattern and mode of spread are different from other malignancies (spread through CSF).
Classification
1. Primary Tumours
(a)
Gliomas

(i) Astrocytic tumours
�

- Pilocytic
�

- Fibrillary
�

- Gemistocytic
�
- Protoplasmic
�

- Anaplastic
�

- Glioblastoma
�

(ii) Oligodendrogliomas

(iii) Ependymomas
(iv) Choroid plexus papillomas

(v) Mixed gliomas
mebooksfree.com