Cytodiagnosis of hydatid disease presenting with Horner's syndrome: a case report

BACKGROUND: The diagnosis of echinococcosis is based on clinical, radiologic and serologic findings. Fine needle aspiration (FNA) is useful in evaluating the lesion when the presentation is atypical. We report a case of hydatid cyst at the lung apex in which the diagnosis was made on FNA, with no adverse reaction to the aspiration. CASE: A 30-year-old male, a chronic smoker, presented with pain radiating to the medial two fingers of the right hand for two years. He also had miosis and ptosis of the right eye and anhidrosis of the right side of theface. There was wasting of small muscles in the right hand. Magnetic resonance imaging revealed a hyperintense mass at the apex of the right lung, thoracic inlet and adjacent vertebral bodies. A clinical diagnosis of Horner's syndrome due to pancoast tumor was rendered. Ultrasound-guided FNA showed protoscolices, scattered hooklets and bits of acellular laminated membrane, characteristic of echinococcosis. Surgical excision of the cyst was done. Gross and histopathologic examination of the excised cyst confirmed the diagnosis. CONCLUSION: FNA, though traditionally contraindicated, is a highly desirable, rapid, noninvasive diagnostic mode for echinococcosis. In view of its pathognomonic cytomorphologic features and numerous reports on cytodiagnosis in the literature, it is time to evaluate the diagnostic benefits and weigh the risks against the advantages of the technique.