Management of Desmoids

Molecular pathogenesis of desmoid tumor and the role of γ-secretase inhibition

Desmoid tumor (DT) is a rare, soft tissue neoplasm associated with an unpredictable clinical course. Although lacking metastatic potential, DT is often locally aggressive and invasive, causing significant morbidity. Both sporadic DT and familial adenomatous polyposis (FAP)-associated DT are linked to constitutive activation of the Wnt signaling pathway with mutations in the β-catenin oncogene CTNNB1 or the tumor suppressor gene APC, respectively. Cross-talk between the Notch and Wnt pathways, as well as activation of the Notch pathway resulting from dysregulation of the Wnt pathway, suggest a possible therapeutic target for DT. Due to the role γ-secretase plays in Notch signaling through cleavage of the Notch intracellular domain (with subsequent translocation to the nucleus to activate gene transcription), γ-secretase inhibitors (GSIs) have emerged as a potential treatment for DT. Two GSIs, nirogacestat (PF-03084014) and AL102 are in later-stage clinical development; nirogacestat is being evaluated in a phase 3, randomized, placebo-controlled trial while AL102 is being evaluated in a phase 2/3, dose-finding (part A) and placebo-controlled (part B) trial. This review summarizes current understanding of the molecular pathogenesis of DT focusing on dysregulation of the Wnt signaling pathway, crosstalk with the Notch pathway, and the potential therapeutic role for GSIs in DT.

A desmoid-type fibromatosis in the retroperitoneum of the gastro-pancreatic region that was resected with a distal pancreatomy: a case report

An 80-year-old man was referred to our hospital because of epigastric pain. Abdominal computed tomography revealed a well-defined circular intra-abdominal mass in the gastro-pancreatic region measuring 15 mm in diameter. After 6 months, the mass lesion was growing with mild enhancement, and weaker enhancement was found in the lower half of the mass on contrast-enhanced computed tomography. The mass lesion touched the stomach, whereas adipose tissue appeared to intervene between the mass and pancreas. On magnetic resonance imaging, the well-defined mass lesion had isointensity to muscle on T1-weighted imaging, slight hyperintensity to muscle on T2-weighted imaging, which indicated a rich fibrous tumor. Under general anesthesia, the patient underwent open surgery. Intraoperatively, the tumor was separated from the stomach and firmly attached to the pancreas. Therefore, we performed a distal pancreatomy with splenic resection. Pathological diagnosis was desmoid-type fibromatosis in the retroperitoneum, and the tumor margin was attached to the pancreas, splenic artery, and splenic vein. Since there are few reports of desmoid-type fibromatosis occurring in the retroperitoneum of the gastropancreatic region, it is difficult to distinguish from other soft tissue tumors and to identify the tumor origin. Close observation by radiological re-valuation was a useful option. Magnetic resonance imaging signals and an enhanced pattern may help distinguish a desmoid-type fibromatosis from other soft tissue tumors. A desmoid-type fibromatosis that is well-defined in radiological findings may infiltrate the surrounding organs with gross or pathological analyses.

High-Intensity Focused Ultrasound Ablation for Postoperative Recurrent Desmoid Tumors: Preliminary Results

This study was aimed at evaluating the feasibility, safety and therapeutic effects of high-intensity focused ultrasound ablation (HIFUA) in the treatment of post-operative recurrent desmoid tumors. From September 2017 to May 2020, 42 consecutive patients with pathologically proven desmoid tumors treated with HIFUA for the first time were enrolled. These were divided into two groups: post-operative recurrent group (30 cases) and non-surgery group (12 cases). The basic characteristics, treatment parameters, ablation efficacy, tolerance and adverse events were recorded and compared between groups. The minimum distance between the tumor and skin surface in the post-operative recurrent group was significantly smaller than that in the non-surgery group (6.9 mm vs. 10.8 mm, p = 0.011), but there was no significant difference in the other basic characteristics (p > 0.05). The average acoustic power and intensity of treatment in the post-operative recurrent group were significantly lower than those in the non-surgery group (p = 0.006 and 0.036, respectively), but there was no significant difference in the remaining parameters or in ablation efficacy between groups (p > 0.05). HIFUA was successfully performed, and a large volume of coagulation necrosis was obtained from all patients without serious or life-threatening adverse events. Furthermore, there was no significant difference in the incidence of moderate adverse events and average length of stay between groups (p > 0.05). The average power and intensity of HIFUA treatment were adversely affected by surgical scar and tumor infiltration along the surgical path. However, HIFUA can still be used as an effective minimally invasive therapy for the local control of post-operative recurrent desmoid tumors.

Mesenteric desmoid tumor: De novo occurrence or recurrence following appendectomy?

Desmoid type fibromatosis (DF) is a rare, locally aggressive but benign proliferation of fibrous tissue which produces a fibroblastic mass that can cause a wide range of symptoms secondary to mass effect. When resected, these masses most commonly recur in the first 2 years. We present a case of a 33-year-old male with a history of an appendectomy 2 years prior, though his pathology report did not identify inflammation in the appendix, who presented with gradual onset of abdominal pain, and radiographs that demonstrated a large mass in the right lower abdomen. Given his symptoms the mass was resected and pathologic evaluation revealed a desmoid tumor. This case presents a unique possibility of a recurrent desmoid tumor in which the patient's surgical history and radiographic findings can contribute to the overall management strategy of the patient given the evolving options for treatment of desmoid fibromatosis.

Rare Mesenchymal Tumors of the Pelvis: Imaging and Pathologic Correlation

Most pelvic tumors originate from the organs. Less commonly, tumors can arise from the various anatomic pelvic compartments and are comprised of mesenchymal tissue: muscles, connective tissue, vessels, lymphatics, and fat. Among some of the rarer entities are benign tumors (eg, angiomyxoma, cellular angiofibroma, and desmoid fibromatosis), malignant tumors (eg, sarcoma), and tumors that can manifest as benign or malignant (eg, solitary fibrous tumor or nerve sheath tumor). Because these tumors are uncommon and often manifest with nonspecific clinical features, imaging (usually MRI) is an initial step in the evaluation. Radiologists interpreting these images are asked to help narrow the differential diagnosis and assess the likelihood of malignancy for treatment planning. Thus, the MRI report should include the imaging features that would indicate the underlying tissue histology for pathologic diagnosis as well as a description of the anatomic extent and pattern of growth. The authors describe multiple locally aggressive benign and malignant mesenchymal tumors and highlight characteristic clinical and imaging features that enable the radiologist to narrow the differential diagnosis. The anatomic spaces of the pelvis are reviewed with illustrations to aid the radiologist in describing these tumors, which often span multiple pelvic compartments. Tumor appearance at T2-weighted, diffusion-weighted, and postcontrast MRI is summarized and illustrated with correlation at CT or fluorodeoxyglucose PET/CT, when available. MRI features that correspond to specific types of tissue (eg, myxoid, fibrous, or vascular) are highlighted and correlated with images from pathologic evaluation. Online supplemental material is available for this article. ^©RSNA, 2021.

Metachronous Sporadic Desmoid Tumors Arisen in the Stomach and the Cecum

Desmoid-type fibromatosis (DF) is a rare soft-tissue tumor demonstrating fibroblastic to myofibroblastic differentiation, recognized as a biologically intermediate, locally aggressive tumor; however, it can be clinically lethal due to its infiltrative growth and risk of locoregional recurrence. Desmoid-type fibromatoses can arise from any part of the body, however, intra-abdominal DFs comprise only 8% of all DFs. We report a case of a male in his 60s who presented with the metachronous occurrence of DF: gastric DF followed by cecal DF with two years of clinical interval. The latter tumor (cecal DF) developed under scheduled postoperative surveillance of laparoscopic gastrectomy. Although a surgical wound is known to be an inductive factor for DFs, the cecal DF developed in a part that was not a surgical site in the previous operation. Curative resection is the first treatment option when the tumor shows progression in size. Following the curative resection, close observation should be provided because of the risk of locoregional recurrence.

Development, Validation, and Visualization of A Web-Based Nomogram for Predicting the Recurrence-Free Survival Rate of Patients With Desmoid Tumors

Background

Surgery is an important treatment option for desmoid tumor (DT) patients, but how to decrease and predict the high recurrence rate remains a major challenge.

Methods

Desmoid tumor patients diagnosed and treated at Tianjin Cancer Institute & Hospital were included, and a web-based nomogram was constructed by screening the recurrence-related risk factors using Cox regression analysis. External validation was conducted with data from the Fudan University Shanghai Cancer Center.

Results

A total of 385 patients were identified. Finally, after excluding patients without surgery, patients who were lost to follow-up, and patients without complete resection, a total of 267 patients were included in the nomogram construction. Among these patients, 53 experienced recurrence, with a recurrence rate of 19.85%. The 3-year and 5-year recurrence-free survival (RFS) rates were 82.5% and 78%, respectively. Age, tumor diameter, admission status, location, and tumor number were correlated with recurrence in univariate Cox analysis. In multivariate Cox analysis, only age, tumor diameter and tumor number were independent risk factors for recurrence and were then used to construct a web-based nomogram to predict recurrence. The concordance index (C-index) of the nomogram was 0.718, and the areas under the curves (AUCs) of the 3-year and 5-year receiver operating characteristic (ROC) curves were 0.751 and 0.761, respectively. In the external validation set, the C-index was 0.706, and the AUCs of the 3-year and 5-year ROC curves are 0.788 and 0.794, respectively.

Conclusions

Age, tumor diameter, and tumor number were independent predictors of recurrence for DTs, and a web-based nomogram containing these three predictors could accurately predict RFS (https://stepforward.shinyapps.io/Desmoidtumor/).

Desmoid-Type Fibromatosis

Desmoid tumors represent a rare entity of monoclonal origin characterized by locally aggressive behavior and inability to metastasize. Most cases present in a sporadic pattern and are characterized by a mutation in the CTNNB1 gene; while 5–15% show a hereditary pattern associated with APC gene mutation, both resulting in abnormal β-catenin accumulation within the cell. The most common sites of presentation are the extremities and the thoracic wall, whereas FAP associated cases present intra-abdominally or in the abdominal wall. Histopathological diagnosis is mandatory, and evaluation is guided with imaging studies ranging from ultrasound, computed tomography or magnetic resonance. Current approaches advocate for an initial active surveillance period due to the stabilization and even regression capacity of desmoid tumors. For progressive, symptomatic, or disabling cases, systemic treatment, radiotherapy or surgery may be used. This is a narrative review of this uncommon disease; we present current knowledge about molecular pathogenesis, diagnosis and treatment.

Clinicopathological characteristics, treatment, and survival outcomes of retroperitoneal desmoid-type fibromatosis: A single-institution experience in China

Retroperitoneal desmoid-type fibromatosis (RPDF) is a rare mesenchymal neoplasm, and it covers a broad spectrum of aggressive monoclonal, fibroblastic proliferation. There is no evidence-based or established optimal treatment available for this intriguing disease yet. Therefore, we here investigated the clinicopathological characteristics, surgical, and survival outcomes in RPDF among Chinese patients.Patients with histologically confirmed RPDF were retrospectively studied from 2010 to 2018 within the West China Hospital of Sichuan University. Demographics, clinicopathological characteristics, treatment, and survival outcome data were collected.Of the 29 cases of RPDF, 19 were females. Tumor diameter ranged from 4 to 40 cm, with a median of 10 cm. Of these patients, surgical resection was the primary treatment adopted for RPDF in 26 cases; while 3 patients underwent watchful waiting. In surgical group, complete and incomplete macroscopic resection was achieved in 21 (80.77%) and 6 (19.23%) cases, respectively. Totally, 21 (80.77%) cases underwent multi-visceral resection. With a median follow-up duration of 48 months, 11 patients experienced tumor progression for the entire cohort. Tumor progression was observed for those patients with incomplete and complete macroscopic resection in 2/5 (40.0%) and 6/21 (28.6%) cases, respectively. In the watchful waiting group, there were no documented cases of RPDF regression. The progression-free survival rate was 86.1%, 71.5%, and 62.3% at 1-, 2-, and 3-years, respectively.RPDFs are rare types of tumor, which have characteristically varied natural histories. Surgical resection had a relative favorable outcome, but some patients were associated with burden of significant surgical complications.

Surgical excision versus observation as initial management of desmoid tumors: A population based study

SYNOPSIS

Desmoid tumors can be safely managed with watchful waiting, including either observation alone or tamoxifen/NSAIDs. Surgery at first presentation can be associated with significant treatment burden.

BACKGROUND

Immediate surgery was historically recommended for desmoid tumors. Recently, watchful waiting, (tamoxifen/NSAIDs or observation alone), has been advocated.

METHODS

All diagnoses of desmoid tumor within the Alberta Cancer Registry from August 2004 to September 2015 were identified. Patients with FAP were excluded. Demographics, tumor characteristics and treatment and outcome data were collected. Outcomes were compared between immediate surgery and watchful waiting. The effect of abdominal wall site on progression and recurrence and the effect of microscopic margin on recurrence were assessed with Fisher's exact test.

RESULTS

We identified 111 non-FAP patients. Median follow-up was 35 months from diagnosis. 74% were female. Mean age was 42. Fifty (45%) underwent watchful waiting, of whom 21(42%) progressed, with median PFS of 10 months. Fifty-three (48%) underwent resection at presentation, of whom 8 (15%) recurred, with median disease-free survival of 22 months. Abdominal wall lesions were equally represented in both groups, and equally likely to progress on watchful waiting (50% vs 39%, p = 0.53), but there was a trend toward decreased recurrence after surgery. (5% vs 23%, p = 0.08). Microscopic margin had no effect on recurrence (14% of margin negative vs 20% of margin positive, p = 1.0).

CONCLUSIONS

Watchful waiting was successful in 58% of patients, and a further 28% only required one aggressive treatment thereafter, for a total of 86%. Surgery had a favorable recurrence rate (15%), but some recurrences were associated with significant treatment burden. Treatment should be tailored to individual patients in a multidisciplinary setting. A trial of observation appears warranted in most patients. Recurrence rate was not affected by positive margins.

Mesenteric fibromatosis misdiagnosed with lymph node metastasis after successful laparoscopic right hemicolectomy: a report of two cases with review of literature

Fibromatosis is a rare type of tumor derived from the mesenchymal tissue. This is a benign tumor with infiltrating growth but may invade locally and recur following excision. As one type of fibromatosis, mesenteric fibromatosis (MF) accounts for a mere 8% of cases. Although studies have revealed that the etiology of MF is related to trauma, surgery, hormones, and heredity, the specific etiology of fibromatosis remains unclear. With such low incidence, MF has been rarely reported and tends to be misdiagnosed due to insufficient recognition. In this paper, we describe the cases of two patients with MF who were misdiagnosed with lymph node metastasis and who had previously undergone successful laparoscopic right hemicolectomy. We provide this information in order to broaden the clinical understanding of MF.

Post-biopsy MRI changes in the size and enhancement of intramuscular myxomas: A report of two cases

Intramuscular myxomas are benign soft-tissue tumors, characterized by bland spindle-shaped cells and fibroblasts within an abundant mucoid matrix on histologic examination. Classically, these are slowly enlarging masses which may occasionally cause pain, paresthesia, and muscle weakness secondary to mass effect. We present an interesting phenomenon of two histologically confirmed cases of intramuscular myxomas that exhibited size and enhancement changes on follow-up imaging after image-guided biopsy. To our knowledge, this is the first report to describe size and enhancement changes of intramuscular myxomas after biopsy.