Cystic endosalpingiosis of lumbar nerve root: a unique presentation

Aims: Endosalpingiosis is a non-neoplastic condition characterized by the presence of ciliated epithelium, resembling tubal epithelium, in heterotopic locations. Its presence has been reported in several anatomical sites in the pelvic, abdominal, and thoracic cavities. Herein we report a rare case of endosalpingiosis presenting as a cystic mass with spinal nerve root attachment. Methods: Clinical history was obtained through review of medical records. The surgical specimen was formalin fixed and paraffin embedded for histological evaluation with hematoxylin and eosin stain and immunohistochemistry. Results: The patient complained of worsening lumbar back pain that started several years before. Magnetic resonance imaging documented the presence of an intradural mass at L1-2. Histological appearance showed a cyst lined by a simple epithelium with ciliated, columnar, and intercalated cells, and immunohistochemistry was positive for keratins, EMA, estrogen, and progesterone receptors, PAX8 and WT1. GFAP and S100 were negative. Ki67 labeling index was low. Conclusion: Endosalpingiosis may rarely involve lumbar nerve roots and must be distinguished from a variety of more common cysts and neoplasms. In view of its potential for neoplastic transformation, recognition of endosalpingiosis may be important in cases with incomplete surgical resection.