Unusual Presentation of an Uncommon Malignancy: A 74-Year-Old Woman with Aggressive Fibromatosis of the Large Intestine Presenting as a Liver Mass and the Therapeutic Management

Objective: Rare disease Background: Desmoid tumors are a fibroblastic proliferation of soft tissues, with an extreme inclination for local dissemination and recurrence. Surgical excision is the usual treatment choice, with data regarding pharmaceutical treatment being scarce. Case Report: A 74-year-old female patient was admitted to "Laikon" General Hospital of Athens, Greece presenting with acute kidney injury secondary to diarrhea. The ultrasound, CT, and abdominal MRI performed showed a 12x6x10 cm tumorous liver lesion. Biopsy of the lesion revealed loosely organized, mesenchymal tissue with spindle cells, and myxoid stroma. Immunochemistry was positive for SMA and b-catenin. Right hemicolectomy was performed with tumor-free surgical margins (R0 resection) and tamoxifen was initiated. Six months after the last MRI (3 months after the use of tamoxifen), a follow-up MRI was performed. The tumor had increased to 14.2x11x12.3 cm, and at the next follow-up it had grown to 20.3x19 cm maximal dimensions; no new metastases were found. The patient received sorafenib and pazopanib. Our patient had PFS with sorafenib for more than 2 years and remained in a good performance status (ECOG 1). For Pazopanid, the median PFS for this treatment option was 6.5 months. Conclusions: The results were good and show a promising method for the treatment of this rare but severe malignancy.