CSF/brain smear cytology - Rcpa.tv

-the cytoplasmic granules stain red with Pap-the cytoplasm usually remains intact as compared with often stripped cytoplasm innon-functioning pituitary adenomasSpindle cell oncocytoma of the anterior hypophysis:-aggregates of spindle cells with elongated tapering granular cytoplasm-cells have ovoid nuclei, conspicuous nucleoli-background of lymphocytes and plasma cells typical (hypophysitis)Chordoma:-cohesive groups, cords and single epithelioid cells with eosinophilic cytoplasm-physaliphorous cells with vacuolated cytoplasm-nuclear pleomorphism is usually mild-prominent mucoid material in the backgroundMetastatic tumours:Metastatic carcinoma:-cohesive groups, papillae, acinar structures, depending on the subtype-cells have well-defined cytoplasmic boundary (poorly defined in astrocytomas)-no fibrillary background-no true endothelial cell proliferation-look for evidence of differentiation e.g. glands, signet-ring cells, mucin,keratinisation, neuroendocrine type featuresFALSE POSITIVES:-normal cerebellar cortex (granule cells) mimicking a small round cell tumour-reactive gliosis difficult to distinguish from a low grade astrocytoma-foamy macrophages (e.g. infarct, demyelination) mistaken for neoplasticgemistocytes-meningiomas can have “epithelioid” cells, mimicking a carcinoma-organising pyogenic abscess / infarct with a rim of endothelial cell hyperplasia-progressive multifocal leukoencephalopathy with reactive astrocytosis-viral encephalitis mimicking a lymphoma-viral inclusions mistaken for malignant epithelioid cells-pineal glial cyst mimicking a pineocytoma or astrocytomaFALSE NEGATIVES:-sampling error by the surgeon (reactive gliosis around the tumour is sampled) ortissue taken by a pathologist for a smear which is not representative-some tumours are hard to smear and the tumour cells are difficult to assess withindense tissue clumps e.g. haemangioblastoma (need to correlate with frozen section)-low grade tumours: astrocytomas, lymphomas-necrotic tumours