Background: Malignant granular cell tumors are among the rarest of soft tissue cancers, currently understood to be of Schwann cell origin. As with their benign counterparts, malignant granular cell tumors (MGCTs) have a wide anatomic distribution and carry a poor prognosis, with recurrence and metastasis typically within 1 year of diagnosis. Only a handful of MGCTs have been described in the pelvis.
Case: We describe a case of malignant granular cell tumor that presented as a pararectal mass associated with severe rectal pain. The patient underwent pelvic exenteration and postoperative radiation therapy. She recurred with evidence of liver metastases on imaging studies 8 months following her exenteration.
Conclusion: We discuss the diagnosis and prognosis of malignant granular cell tumors arising in the pelvis.