Cytologic findings of urogenital mesenteric cyst.

Mesenteric cysts are heterogeneous groups of lesions. Most of them are developmental cysts of lymphatic and enteric origin or cystic neoplasm such as mesothelioma or cystic teratoma. Urogenital cysts are a subcategory of developmental cysts of the mesentery. They are thought to arise from vestigial remnants of urogenital apparatus. These cysts may show evidence of mesonephric or metanephric differentiation. An 11 -year -old boy was presented with undescended testis. During preoperative work- up, an incidental cystic lesion was discovered which was attached to the ileum. Aspiration cytology of the cyst content revealed cuboidal to columnar cells; some of them were ciliated. Histologic examination showed a cyst with fibromuscular wall, lined by Mullerian type ciliated epithelium; so the diagnosis of urogenital mesenteric cyst of Mullerian type was made. Urogenital cysts are rare lesions, but they should be considered in differential diagnosis of any cystic lesion of the mesentery. Cytology could be a useful method for evaluation and revealing the nature of these cysts.