Paragangliomas--a diagnostic dilemma on fine needle aspirates.

Paragangliomas are uncommon tumours arising from the neural crest and are widely distributed throughout the body. Because of the morphologic diversity of these tumours fine needle aspirate (FNA) diagnosis is not very accurate in identifying these neoplasms. Review of FNA from seven paragangliomas (three extra-adrenal, three carotid body and one multicentric in location) was conducted to find any diagnostic criteria. On initial morphologic diagnosis five of the seven paragangliomas were considered malignant (four undifferentiated and one adenocarcinoma). Review of these cases in our series made us wiser. Pleomorphic nuclei, prominent nucleoli, clumped chromatin with finely granular cytoplasm and occasional intranuclear cytoplasmic inclusions were characteristically seen and these were probably the cause for misdiagnosis. This lesion must be entertained in an aspirate from the neck or retroperitoneum which contains cells showing marked nuclear pleomorphism with naked nuclei and have a tendency to spindle or from acini. To confirm these cases argyrophilic granules were demonstrated in two of the four cases studied. However, neuron specific enolase and calcitonin were found to be non-contributory. Ultrastructural examination was helpful and done in one case showed abundant neurosecretory granules.