Anatomy and Pathology of the Ischiorectal Fossa

Ten-Step Surgical Approach to Management of Pathology of the Ischiorectal Fossa-A Review of the Literature and Application in a Rare Pelvic Schwannoma

Objective: The ischiorectal fossa is a key anatomical location with boundaries and internal structures owing distinct contributions to function and quality of life. Methods: We highlight the importance of management of pathology in this deep anatomically complex location. Results: We present a ten-step multidisciplinary surgical approach; achieving en bloc radical excision with primary closure and reassuring outcomes. Schwannomas are benign slow-growing nerve sheath tumors. Conclusions: Pelvic schwannomas are rare with only 3 reported cases of the pudendal nerve. We also offer an overview of this rare pathology whilst acknowledging a paucity of recommendations regarding management of disease of the ischiorectal fossa.

Aggressive angiomyxoma presenting as an ischiorectal fossa tumour

This is a case of a young healthy woman who presented with left groin pain. On work-up, she was found to have a large, well-defined mass in the ischiorectal fossa with a percutaneous biopsy of only a benign mesenchymal mass. A multidisciplinary team of surgeons (ie, colorectal, orthopaedic, vascular and urological surgery) collaborated in planning and performing the extirpation of the tumour. Final histopathology identified the tumour to be an aggressive angiomyxoma, a benign tumour with a high predilection for local recurrence. The patient had an uneventful postoperative course, with maintenance of good functional status.

Ischiorectal fossa: benign and malignant neoplasms of this "ignored" radiological anatomical space

PURPOSE

To review the pertinent anatomy and the imaging features of common and uncommon benign and malignant neoplasms and masses of the ischiorectal fossa.

RESULTS

The ischiorectal or ischioanal fossa is the largest space in the anorectal region. The benign neoplasms that develop in the ischiorectal originate from the different components that forms the fossa including vascular tumors such as aggressive angiomyxoma or hemangioma; neural tumors as plexiform neurofibroma or schwannoma; fat tumors as lipoma; skin/skin appendages tumors as hidradenoma papilliferum; smooth or skeletal muscle tumors as solitary fibrous tumor. The malignant neoplasms that develop in the ischiorectal fossa also originate from different components that forms the fossa including vascular tumors such as angiosarcoma, neural tumors as malignant granular cell tumor and malignant peripheral nerve sheath tumor; fat tumors as liposarcoma; smooth or skeletal muscle tumors as leiomyosarcoma, rhabdomyosarcoma, malignant PEComa, or undifferentiated pleomorphic sarcoma. Additionally, the ischiorectal fossa can also harbor secondary hematogenous metastases and be affected by direct invasion from neoplasms of adjacent pelvic organs and structures. Furthermore, other miscellaneous masses can occur in the ischiorectal fossa including congenital and developmental lesions, and inflammatory and infectious processes.

CONCLUSION

Knowledge of the anatomy, and the spectrum of imaging findings of common and uncommon benign and malignant neoplasms of the ischiorectal fossa is crucial for the radiologists during interpretation of images allowing them to make contributions to the diagnosis and better patient management.