Pazopanib monotherapy in a patient with a malignant granular cell tumor originating from the right orbit: A case report.

Granular cell tumors are uncommon, usually benign tumors of Schwann cell origin. The malignant variant is extremely rare, representing <2% of all granular cell tumors. Therefore, standard systemic chemotherapy for this disease does not exist. The present study reports the case of a 40-year-old female with a malignant granular cell tumor that originally arose in the right orbit and subsequently relapsed. The patient was started on pazopanib monotherapy following treatment with two investigational drugs, a smoothened inhibitor and then a phosphatidylinositol 3-kinase inhibitor, as part of a clinical trial. Although additional radiotherapy for local control was necessary, the lung metastases remained stable during the pazopanib monotherapy, which lasted for 7 months, following which a clinically stable disease state was determined. This case suggests that pazopanib can be a treatment option for the stabilization of disease progression in metastatic malignant granular cell tumor.