Significance of AgNOR in Salivary Gland Tumours.

Diagnosis of Salivary gland tumours is challenging, because of wide variation in differentiation and overlapping morphological features. Sometimes, the difficulty encountered in distinguishing between pleomorphic adenoma, adenoid cystic carcinoma and adenocarcinoma. The objective is to study the application of AgNOR pattern in differentiating benign and malignant tumours of the salivary glands on Fine needle aspirates and their correlation with histopathology. Material and method: Cytological material was obtained by FNAC from forty three patients of salivary gland tumours. MGG and Pap stained smears were prepared for cytological interpretation. Histopathological study was done on routine formalin fixed and Haematoxylin & Eosin stained sections. Smears and sections were stained with Silver colloid stain for study of AgNOR counting. Results: AgNOR in benign tumours were small, round, uniform and less in number (1.02-1.97) while in malignant tumours they were very large, irregular, haphazardly distributed with high counts (1.23-16). Conclusion: Present study shows that count as well as morphology of AgNOR dots was helpful in differentiating between benign and malignant tumours and their grading of malignancy .

Pilomyxoid astrocytoma.

Pilomyxoid astrocytoma (PMA) is a recently described brain tumor. PMA shares similar features with pilocytic astrocytoma (PA), the most common central nervous system (CNS) tumor in the pediatric population, yet displays subtle histologic differences. We describe a case of PMA in a six-year-old male involving sellar and suprasellar region presenting with failure to thrive and delayed developmental milestones. The histological findings revealed a tumor composed of a monotonous population of loosely arranged cells with delicate piloid like processes, within a prominent myxoid background. The tumor lacked biphasic appearance, Rosenthal fibers, eosinophilic granular bodies and calcification that are commonly observed in classical PA. Previous studies have shown PMA to behave more aggressively than PA, with shorter progression-free survival as well as a higher rate of recurrence and CNS dissemination. Thus, recognition of PMA and its distinction from classical PA is very important.