A case of progressing mesenteric desmoid fibromatosis: A diagnostic and therapeutic challenge

Summary

Background: Desmoid fibromatoses are rare, benign neoplasms of myofibroblast origin that lack metastatic potential but can be locally invasive. Diagnosis and management is challenging as it is based on factors such as symptomatology, tumor location, risk or recurrence and the possibility of treatment-induced morbidity. Case Presentation: A healthy 48 year old Filipino woman presents with an 2x3 cm incidental jejunal mesenteric mass found intraoperatively during the excision of her choledochal cyst. Histopathology of the core-needle biopsy revealed desmoid fibromatosis. An initial watchful waiting approach was employed since the patient was asymptomatic and resection would cause significant bowel loss. After three months, her abdominal CT scan shows that the mass had progressed, to 4.7 x 4.5 x 4.7cm. Anti-hormonal therapy with high-dose Tamoxifen (120mg daily) was initiated due to its limited toxicity and low cost. The patient is currently asymptomatic, on her third month of treatment. Her latest abdominal scan shows stable disease. Discussion: Watchful waiting is an appropriate first-line option, especially in asymptomatic tumors and those found in non-critical locations. In case of progression, management should be site specific and via a stepwise approach. Therapeutic toxicities, such as significant intestinal loss upon resection, should be carefully weighed before choosing treatment. Preferred initial management has now shifted towards non-surgical approaches or systemic therapies such as high dose tamoxifen, NSAIDs, tyrosine-kinase inhibitors (sorafenib, pazopanib and imatinib) and chemotherapy (methotrexate and vinblastine, and pegylated doxorubicin). A stepwise escalation of therapy from less to more toxic agents are now a reasonable approach. Conclusion: Desmoid fibromatosis represents a benign histology with a malignant and unpredictable course. An upfront multidisciplinary team approach is recommended to ensure proper treatment and surveillance.