A Tailgut Cyst Diagnosed by Endoscopic Ultrasound-Guided Fine-Needle Aspiration

Tailgut cysts are rare developmental cysts. Surgery has been the primary method of diagnosis and treatment of these cysts, but endoscopic ultrasound (EUS) has recently been used to establish diagnosis. Only 2 cases of tailgut cyst diagnosed by EUS-guided FNA have been reported. We present a woman in her fourth decade who presented for evaluation of perirectal mass. EUS-guided fine-needle aspiration (FNA) helped establish the diagnosis of tailgut cyst. The patient opted for observation rather than surgery.