Complete Response to Sorafenib in Locally Recurrent Unresectable Aggressive Fibromatosis

Abstract

A 48-year-old female patient presented with a 5 cm mass in the left supra-clavicular fossa of 12-months duration, progressively increasing in size. A biopsy revealed a spindle cell neoplasm arranged in long fascicles, positive for B-catenin and focally positive for smooth muscle actin [Figure 1]. A diagnosis of aggressive fibromatosis was established. The mass was surgically excised, the resection margin was positive and the diagnosis was consistent with aggressive fibromatosis. The mass recurred within three months of resection and the patient presented to the clinic with a 7 × 5 cm lobulated, hyper-attenuated soft tissue mass at the left posterior cervical region extending to the infraclavicular region abutting the muscles. There were no co-morbidities and the performance status on the WHO scale was 1. The patient was commenced on celecoxib. An MRI demonstrated a locally advanced disease [Figures 2A, B and C]. Due to the increasing pain and a lack of clinical response over three months while on celecoxib, the patient was commenced on a multi-tyrosine kinase inhibitor, sorafenib, at a standard dose of 400 mg twice daily. Within two weeks after starting sorafenib, the patient developed a generalised rash with itching, aches and pains, fatigue, blisters over the sole of the left foot and diarrhea. The patient had then stopped using sorafenib. Full blood count, renal, liver and thyroid function tests remained within the normal limits. Three weeks later, after the rash and the blister had settled, the patient has commenced again on sorafenib at a reduced dose of 200 mg twice daily. The patient developed grade III hand-foot syndrome as the mass clinically decreased in size. The frequency of sorafenib was reduced to once daily and the patient maintained this treatment for a total of 11 months. A follow-up MRI revealed a complete radiological response [Figures 2D, E and F]. She was then referred for adjuvant radiotherapy.