Desmoid fibromatosis involving the pancreas: A retrospective case series with clinical, cytopathologic and radiologic correlation

Desmoid-type fibromatosis (desmoid tumors) which involve the pancreas is an infrequent diagnosis which clinically can mimic both neoplastic and non-neoplastic lesions of the pancreas. The cytologic features of loosely cohesive cytologically bland (myo)fibroblastic cells are non-specific, however the long fascicular growth pattern and the presence of β-catenin mutation with positive nuclear immunohistochemical staining or molecular testing allows for definitive diagnosis. While many previously reported desmoid tumors of the pancreas have been surgically resected, conservative management with a “watch and wait” approach is also an effective mode of management for these tumors. Herein, we report the largest case series of pancreatic desmoid tumors with clinical, cytopathologic, and radiologic correlation.

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 2×3 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.

Desmoid tumors (DTs), also known as desmoid fibromatosis or aggressive fibromatosis, are rare, locally invasive, non-metastatic soft tissue tumors. Although histological results represent the gold standard diagnosis, imaging represents the fundamental tool for the diagnosis of these tumors. Although histological analysis represents the gold standard for diagnosis, imaging represents the fundamental tool for the diagnosis of these tumors. DTs represent a challenge for the radiologist, being able to mimic different pathological conditions. A proper diagnosis is required to establish an adequate therapeutic approach. Multimodality imaging, including ultrasound (US), computed tomography (CT) and Magnetic Resonance Imaging (MRI), should be preferred. Different imaging techniques can also guide minimally invasive treatments and monitor their effectiveness. The purpose of this review is to describe the state-of-the-art multidisciplinary imaging of DTs; and its role in patient management.

Aim: To report the first UK experience of cryoablation in desmoid fibromatosis (DF) with particular focus on technique, safety, and efficacy. Materials and methods: Patients were selected at multidisciplinary tumour board meetings at a specialist cancer hospital. Radiation dose, procedure duration, and number of cryoprobes were compared for small versus large tumours (>10 cm long axis). Response at magnetic resonance imaging (MRI) was evaluated using different criteria, and percentage agreement with clinical response as assessed in oncology clinic calculated. Results: Thirteen procedures were performed in 10 patients (eight women, median age 51 years, IQR 42-69 years) between February 2019 and August 2021. Procedures for large tumours had higher radiation dose (2,012 ± 1,012 versus 1,076 ± 519 mGy·cm, p=0.048) used more cryoprobes (13 ± 7 versus 4 ± 2, p=0.009), and were more likely to have residual unablated tumour (38 ± 37% versus 7.5 ± 10%, p=0.045). Adverse events were minor apart from one transient radial nerve palsy. Eight of 10 patients had symptomatic benefit at clinical follow-up (median 353 days, IQR 86-796 days), and three started systemic therapy mean 393 days later. All patients who had complete ablation demonstrated symptomatic response, with no instances of repeat treatment, recurrence, or need for systemic therapy during the study period. All progression occurred outside ablation zones. Conclusion: Cryoablation for symptomatic DF is a reproducible technique with low, transient toxicity, where one or two treatments can achieve a meaningful response. Where possible, the ablation ice ball should fully cover DF tumours.

Background: Desmoids are rare fibroblastic tumours whose treatment in any individual case presents a persistent challenge. We endeavoured to evaluate various clinicopathological factors contributing to tumour behaviour. Methods: This is a retrospective review of 95 primary truncal sporadic fibromatosis managed between 2011 and 2020. We studied progression rate for wait and watch (WW) and recurrence rate for the surgically treated group as adverse events. Relevant event-free survivals and potential risk factors were analysed over a median follow-up of 27 months. Results: 66 patients (69.5%) received watchful surveillance and 28 upfront surgery. 2-year progression-free survival in WW group (88.9%) was higher than RFS in the surgical group (77.1%) p = 0.02. Adverse event rate compared favourably, 28.8% in WW and 28.6% in surgical group. At final follow-up, rate of stable disease for WW was 47%, and the regression rate was 24.2%. On Cox regression analysis, meantime to progress was 14 ± 2.0 months, with larger tumour size as a significant prognostic indicator (p = 0.05). Surgical group’s mean time to recurrence was 13.8 ± 2.76 months, with tumour location a significant contributing factor (p = 0.05). Conclusions: This study confirms to the safety of both treatment approaches. Adverse event rates remained comparable, but event-free survival was longer for the watchful surveillance group.

Purpose of review: The objective of this article is to summarize new treatment strategies of desmoid tumors. Recent findings: Desmoid tumor has an unpredictable evolution that may spontaneously regress or stabilize. A shift toward an initial frontline active surveillance has been acknowledged by experts. Surveillance monitoring should be performed frequently after the diagnosis to avoid missing a significant progression and then spaced in case of stabilization. Treatment is based on significant tumor growth or symptoms. Recent guidelines recommend commencing medical treatment. Kinase inhibitors and cytotoxic agents are the two classes of drugs where studies included progressive desmoid tumors and should be selected to guide medical practice. In a randomized trial, 2 years progression-free survival (PFS) was significantly better in the sorafenib group (81 versus 36% in the placebo group). In another randomized phase 2, 6 months PFS was 83.7% with pazopanib versus 45% with methotrexate and vinblastine. In a retrospective study, including progressive desmoid tumors, methotrexate + vinca alkaloids achieved 75 months median PFS. Cryotherapy is an alternative option in desmoid tumors with compatible locations and tumor sizes. Following medical treatment or cryotherapy failure, superficial sites represent the best indications for surgery in cases of continuous progression. In the event of a contra-indication or failure of medical treatment, in locations where surgery would be mutilating and incomplete, radiotherapy is an effective option. Summary: Active surveillance with planned imaging has become the first-line management in desmoid tumor.