Multimodality imaging features of desmoid tumors: a head-to-toe spectrum

Contrast enhanced ultrasound versus MRI for response assessment of extra-abdominal desmoid Fibromatosis- A feasibility study

BACKGROUND

Desmoid Fibromatosis (DF) is a locally aggressive soft tissue tumor which was traditionally managed with surgical excision. However due to high rates of local recurrence and insights about its behavior, there is now a paradigm shift towards active surveillance and medical management. Imaging plays a crucial role in surveillance and treatment response; however, conventional RECIST criteria are not adequate for DF. MRI is the preferred modality but faces limitation in availability and uniformity. Although ultrasound (US) is not optimal for evaluation, contrast enhanced US has shown promising results in many solid tumors.

OBJECTIVES

To explore the role of Contrast Enhanced Ultrasound (CEUS) as a response assessment tool in DF.

MATERIALS AND METHODS

This was a prospective study conducted between March 2022 and December 2023 and included 21 adults with DF who received medical line of treatment. A combination of clinical evaluation for symptom relief, and imaging modalities using MRI and CEUS, were utilized for response assessment. Statistical analysis was performed using non parametric tests.

RESULTS

Out of 21, 19 patients underwent pre as well as post-treatment evaluation. Clinical improvement was reported by 73.68 % while MRI indicated response only in 41.18 %; whereas only 29.41 % met the criteria for partial response according to RECIST 1.1. All responders on MRI exhibited continued enhancement on CEUS with a significant decrease in Mean Transit Time (MTT, p = 0.047).

CONCLUSION

CEUS demonstrates potential as an effective treatment response tool in DF, providing real-time information of microvascular changes within the mass.

Giant desmoid tumor of the abdominal wall: a case report

INTRODUCTION AND IMPORTANCE

Desmoid tumors are a rare type of benign fibromatosis. Patients often present with a painless abdominal mass. Here, we report a case of a giant desmoid tumor of the abdominal wall that was successfully treated with wide local excision.

CASE PRESENTATION

We present the case of a 48-year-old female who developed an abdominal mass over the past year. Imaging revealed a well-circumscribed mass on the left side of the abdomen, which was treated with wide local excision. Immunohistochemical analysis of the specimen confirmed the diagnosis of a desmoid tumor. The patient had an uneventful postoperative recovery and remained in remission during an 18-month follow-up period.

DISCUSSION

Desmoid tumors are very rare benign lesions that typically affect young women. Abdominal wall localization is more common in individuals with Gardner syndrome. Surgery remains the primary treatment, with the approach depending on the size and location of the lesion. Radiotherapy is considered an alternative for tumors that are unresectable or incompletely excised. The definitive diagnosis requires immunohistochemical analysis of the specimen.

CONCLUSION

Desmoid tumors are benign fibromatoses that can occur in the abdominal wall. Symptoms are typically non-specific. Surgery is the main treatment, always aiming for radical resection with free margins. Histological analysis of the surgical specimen is crucial for confirming the diagnosis.

Radiological features of desmoid-type fibromatosis: a two-institution retrospective study

OBJECTIVES

To characterize the radiological findings of desmoid-type fibromatosis (DF).

METHODS

This two-institution retrospective study included 152 patients with pathologically confirmed DF who underwent computed tomography (CT), magnetic resonance imaging (MRI), or 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT between January 2001 and February 2024. Two board-certified radiologists independently evaluated the CT, MRI, and FDG-PET/CT findings, and a third board-certified radiologist resolved discrepancies. Imaging was performed with and without contrast media: 70 patients underwent plain CT, 95 underwent contrast-enhanced (CE) CT, 115 patients underwent plain MRI examinations, 100 patients underwent CE-MRI, and 11 patients underwent FDG-PET/CT (most patients underwent several modalities).

RESULTS

The median age of the patients was 40 years, with a female predominance (male, 39.5% vs female, 60.5%). Swelling or palpable mass was the most frequent symptom (78/152, 51.3%). Gross total resection of DF was performed in 57 patients, with a recurrence rate of 38.6% (22/57). Tumors were most frequently observed in the extra-abdominal region (79/152, 51.6%). Characteristic radiological features included intermediate intensity on T2-weighted imaging (112/113, 99.1%), intermediate-to-high intensity on T1-weighted imaging (109/111, 98.2%), substantial enhancement in the late phase on MRI (100/100, 100%), moderate to strong enhancement in the late phase on CT (18/20, 90%), and arterial penetration sign on CE-CT (25/96, 26.0%). The mean apparent diffusion coefficient (ADC) of DFs was 1.46 × 10-3 mm2/s (range, 1.00-2.20).

CONCLUSION

This study highlights the unique imaging features of DF, including the arterial penetration sign and high mean ADC values, which can aid in differentiating DF from other soft tissue tumors. These findings may improve preoperative diagnostic accuracy and reduce the need for invasive procedures.

KEY POINTS

Question Imaging findings of DF are not well-documented in large-scale studies. Findings This study identifies unique imaging features of DF, such as the arterial penetration sign and high mean ADC values. Clinical relevance These distinctive imaging characteristics improve diagnostic accuracy for DF and lead to appropriate patient management, as DF requires distinct treatment strategies.

Mesenteric desmoid tumor in its cystic form: Case report of a very rare variant

Desmoid tumors, also known as deep fibromatosis or desmoid-type fibromatosis, represent a rare subset of deep fibromatoses. It is a locally aggressive tumor, with no specific symptoms, and no metastatic potential. We report a case of a 38-year-old male patient with an abdominal mass. Radiological findings showed 2 tumors, the first was a solid inguinal mass of the left lateral iliac pedicle, and the second was a giant cystic mass in the abdominal cavity. An elective explorative laparotomy was performed to remove the 2 masses. Histopathological examination confirmed the desmoid tumor diagnosis of both lesions.

MRI Characteristics for Distinguishing Solitary Fibrous Tumor From Desmoid Tumor

OBJECTIVE

To elucidate the magnetic resonance imaging (MRI) characteristics for distinguishing solitary fibrous tumors (SFTs) from desmoid tumors (DTs).

MATERIALS AND METHODS

A retrospective study of 66 consecutive patients with histopathologically proven SFT (n = 34; 13 males and 21 females; mean age, 52.0 ± 17.1 years) or DT (n = 32; 11 males and 21 females; mean age, 39.0 ± 21.3 years) was conducted. The two groups were quantitatively compared in terms of the size, signal intensity ratio (SIR), and apparent diffusion coefficient value. For qualitative analysis, the tumor location, boundary, shape, internal uniformity, predominant signal intensity, T1-weighted images (T1WI) characteristics (hyperintense area), T2-weighted images (T2WI) characteristics (hypointense area, marked hyperintense area, flow void, band sign, and yin-yang sign), and contrast-enhanced T1WI characteristics (unenhanced area and degree of enhancement) were compared between the two groups. Multiple stepwise logistic regression analyses were conducted to distinguish between the SFT and DT.

RESULTS

T1 (P = 0.010) and T2 (P = 0.026) SIRs were higher in SFTs than in DTs. Hyperintense areas on T1WI (P < 0.001), marked hyperintense areas on T2WI (P = 0.025), and flow void (P = 0.025) were more frequently noted in SFTs. On T1WI, the solid component predominantly revealed hyperintensity in SFTs and isointensity in DTs (P < 0.001). Indistinct tumor boundary (P < 0.001), hypointense area on T2WI (P < 0.001), and band sign (P < 0.001) were more frequently observed in DTs. Multiple stepwise logistic regression analysis revealed that the hyperintense area on T1WI (odds ratio favoring SFT, 12.80, P = 0.002) and band sign (odds ratio favoring DT, 0.03; P < 0.001) were independent predictors.

CONCLUSION

MRI characteristics can help distinguish SFT from DT. The presence of a hyperintense area relative to the skeletal muscle on T1WI in SFTs and the band sign on T2WI in DTs are important MRI features.

MRI features that predict progression of residual disease after ablation of extra-abdominal desmoid fibromatosis

OBJECTIVE

To identify MRI features of desmoid tumors (DTs) that predict the growth of residual disease following ablation.

METHODS

Patients who underwent MRI-guided ablation for DTs between February 2013 and April 2021 were included in this single-center IRB-approved retrospective study. MRI scans assessed three suspicious tissue features: intermediate T2 signal [+iT2], nodular appearance [+NOD], and contrast enhancement [+ENH]. Percent-monthly change in diameter (PMCD) of suspicious foci determined growth (PMCD > 1%), unchanged (PMCD between -1% and +1%), or regression (PMCD < -1%). Statistical tests compared mean PMCD between groups and evaluated sensitivity and specificity.

RESULTS

Thirty-three patients (32 years ± 13.3; 22 females) with 34 DTs underwent 47 MRI-guided ablations, with a median follow-up of 269 days (IQR 147). Of 93 suspicious foci, 62 (67%) grew (PMCD: +5.6% IQR: 5.8), 13 (14%) remained unchanged (PMCD: -0.1% IQR: 0.6), and 18 (19%) regressed (PMCD: -3.9% IQR: 4.2). Features [+iT2], [+ENH], and [+NOD] were associated with PMCDs of +5.2% IQR: 6.0, +3.4% IQR: 6.0, and +3.4% IQR: 6.5, respectively, compared to -1.5% IQR: 4.7 (p < 0.0001), -0.5% IQR: 0.8 (p = 0.003), and +0.4% IQR: 7.5 (p = 0.0056) for their respective negative counterparts. Sensitivity, specificity, and accuracy for distinguishing growth were [+iT2]: 0.95, 0.71, 0.87, [+ENH]: 1.00, 0.32, 0.77, and [+NOD]: 0.84, 0.42, 0.70. Combining [+iT2 + NOD + ENH] yielded PMCD +5.9% IQR: 6.2 and the best performance for distinguishing growth (sensitivity 0.81, specificity 0.94, accuracy 0.85).

DISCUSSION

MRI features reliably predict the growth of residual or recurrent DTs post-ablation, with [+iT2] being the most accurate. Adding nodular enhancement to [+iT2] improved specificity without sacrificing accuracy.

KEY POINTS

Question Post-ablation imaging of desmoids is challenging due to tumor heterogeneity and treatment-related inflammation. This study evaluates MRI features for assessing future tumor growth. Findings Foci of intermediate T2 signal post-ablation predicted desmoid growth with high sensitivity (0.95), while T2 signal, nodularity, and enhancement combined offer high specificity (0.94). Clinical relevance Intermediate T2 signal predicts desmoid tumor growth post-ablation with high sensitivity and accuracy but moderate specificity. Combining nodularity and enhancement improves specificity and predictive value, helping clinicians in managing desmoid tumor patients post-ablation.

Desmoid Tumor after Sleeve Gastrectomy: Case Report and Literature Review

Desmoid tumor is a rare mesenchymal neoplasm of unknown etiology. Despite rare, the diagnosis of desmoid tumors after bariatric surgery is increased over the last few years. We report a case of a 26-year-old male with complains of abdominal pain and postprandial fullness, diagnosed with a locally advanced large intra-abdominal mass (40 × 21 × 11.7 cm) centered in the mesentery, developed 3 years after sleeve gastrectomy. Percutaneous biopsy was suggestive of a mesenquimatous tumor and the patient underwent surgery. R0 surgical resection was achieved, despite intimal contact and common vascularization with a jejunal loop. Histopathology examination of the surgical specimen revealed fusiform to stellate cells with mild atypia, thin-walled vessels, and diffuse beta-catenin expression (negative for DOG-1, CD117, CD34, S100, desmin, and alpha-actin). The diagnosis of a desmoid tumor was made. The patient remained asymptomatic, and no recurrence occurred over a 4-year follow-up. With the increasing number of bariatric surgeries, owing to the alarming growing incidence of obesity and related conditions, it is expected that desmoid tumors reports will gradually increase over the next few years. Thus, both gastroenterologists and surgeons should be aware of the potential for desmoid tumor development shortly after surgery, to offer a prompt diagnosis and treatment.

Endometriosis MR mimickers: T2-hypointense lesions

Endometriosis is a common crippling disease in women of reproductive age. Magnetic resonance imaging (MRI) is considered the cornerstone radiological technique for both the diagnosis and management of endometriosis. While its sensitivity, especially in deep infiltrating endometriosis, is superior to that of ultrasonography, many sources of false-positive results exist, leading to a lack of specificity. Hypointense lesions or pseudo-lesions on T2-weighted images include anatomical variants, fibrous connective tissues, benign and malignant tumors, feces, surgical materials, and post treatment scars which may mimic deep pelvic infiltrating endometriosis. False positives can have a major impact on patient management, from diagnosis to medical or surgical treatment. This educational review aims to help the radiologist acknowledge MRI criteria, pitfalls, and the differential diagnosis of deep pelvic infiltrating endometriosis to reduce false-positive results. Critical relevance statement MRI in deep infiltrating endometriosis has a 23% false-positive rate, leading to misdiagnosis. T2-hypointense lesions primarily result from anatomical variations, fibrous connective tissue, benign and malignant tumors, feces, surgical material, and post-treatment scars. Key points • MRI in DIE has a 23% false-positive rate, leading to potential misdiagnosis.• Anatomical variations, fibrous connective tissues, neoplasms, and surgical alterations are the main sources of T2-hypointense mimickers.• Multisequence interpretation, morphologic assessment, and precise anatomic localization are crucial to prevent overdiagnosis.• Gadolinium injection is beneficial for assessing endometriosis differential diagnosis only in specific conditions.

Diffuse-Type Tenosynovial Giant Cell Tumor: What Are the Important Findings on the Initial and Follow-Up MRI?

Tenosynovial giant cell tumor (TSGCT) is a rare soft tissue tumor that involves the synovial lining of joints, bursae, and tendon sheaths, primarily affecting young patients (usually in the fourth decade of life). The tumor comprises two subtypes: the localized type (L-TSGCT) and the diffuse type (D-TSGCT). Although these subtypes share histological and genetic similarities, they present a different prognosis. D-TSGCT tends to exhibit local aggressiveness and a higher recurrence rate compared to L-TSGCT. Magnetic resonance imaging (MRI) is the preferred diagnostic tool for both the initial diagnosis and for treatment planning. When interpreting the initial MRI of a suspected TSGCT, it is essential to consider: (i) the characteristic findings of TSGCT-evident as low to intermediate signal intensity on both T1- and T2-weighted images, with a blooming artifact on gradient-echo sequences due to hemosiderin deposition; (ii) the possibility of D-TSGCT-extensive involvement of the synovial membrane with infiltrative margin; and (iii) the resectability and extent-if resectable, synovectomy is performed; if not, a novel systemic therapy involving colony-stimulating factor 1 receptor inhibitors is administered. In the interpretation of follow-up MRIs of D-TSGCTs after treatment, it is crucial to consider both tumor recurrence and potential complications such as osteoarthritis after surgery as well as the treatment response after systemic treatment. Given its prevalence in young adult patents and significant impact on patients' quality of life, clinical trials exploring new agents targeting D-TSGCT are currently underway. Consequently, understanding the characteristic MRI findings of D-TSGCT before and after treatment is imperative.

The Notch signaling pathway in desmoid tumor: Recent advances and the therapeutic prospects

Desmoid tumor (DT) is a rare fibroblastic soft-tissue neoplasm that is characterized by local aggressiveness but no metastatic potential. Although the prognosis is relatively favorable, the unpredictable disease course and infiltrative growth lead to significant impairments and morbidity. Aberrant activation of Wnt/β-catenin signaling has been well-established in the pathogenesis of sporadic DT and familial adenomatous polyposis (FAP) or Gardners syndrome-associated DT, suggesting therapy targeting this pathway is an appealing treatment strategy. However, agents against this pathway are currently in their preliminary stages and have not yet been implemented in clinical practice. Increasing studies demonstrate activation of the Notch pathway is closely associated with the development and progression of DT, which provides a potential alternative therapeutic target against DT. Early-stage clinical trials and preclinical models have indicated that inhibition of Notch pathway might be a promising treatment approach for DT. The Notch signaling activation is mainly dependent on the activity of the γ-secretase enzyme, which is responsible for cleaving the Notch intracellular domain and facilitating its nuclear translocation to promote gene transcription. Two γ-secretase inhibitors called nirogacestat and AL102 are currently under extensive investigation in the advanced stage of clinical development. The updated findings from the phase III randomized controlled trial (DeFi trial) demonstrated that nirogacestat exerts significant benefits in terms of disease control and symptom resolution in patients with progressive DT. Therefore, this review provides a comprehensive overview of the present understanding of Notch signaling in the pathogenesis of DT, with a particular emphasis on the prospective therapeutic application of γ-secretase inhibitors in the management of DT.

Diffusion weighted imaging changes in extra-abdominal desmoid tumor after cryotherapy

Desmoid tumors (DT) are rare benign tumors with a local invasion potential and recurrence. It is characterized on histology by an abnormal fibroblastic proliferation in a collagenous stroma, in variable proportions leading to heterogeneity of the lesion signal on magnetic resonance imaging (MRI). Current guidelines propose watchful waiting but in case of progression or symptoms, cryotherapy may be a therapeutic option in its extra-abdominal form. Tumor recurrence is mostly detected based on post-contrast magnetic resonance imaging (MRI). Although DWI sequence is the key-sequence for tumor detection in oncologic imaging, there are very few data in literature on diffusion weighted imaging (DWI) in DT generally and even fewer on DT after cryotherapy. DWI changes after cryotherapy may be confusing and suspicious of residual tumor or tumor recurrence when displaying low ADC values; thus knowledge of possible DWI patterns after cryotherapy of DT seem paramount. We found that the early changes of DT after cryotherapy are hyperintensity on DWI sequence with low ADC values (<1.00 × 10^-3mm²/s), without corresponding enhancement and a later decrease in signal of the treated lesion on DWI. The freezing-thawing cycles of cryotherapy turn DT into gelatinous necrosis with a slow resorption rate, as reported in the only few studies referring of changes of DWI signals after cryotherapy, which are on renal and prostate models. Hyperintensity on DWI with low ADC values may be seen in early MRI follow-up after cryotherapy of extra-abdominal DT, corresponding with tumor necrosis changes and should not be mistaken with recurrence.KEY MESSAGESMagnetic resonance imaging is the modality of choice for desmoid tumor (DT) follow-up, mainly based on contrast uptake which make data on diffusion weighted imaging (DWI) very rare.Cryotherapy is an accepted therapeutic option for DT that will lead to tumor necrosis.Hyperintensity on DWI with low apparent diffusion coefficient values is a possible expected early pattern on DWI after cryotherapy of DT.

Update on Familial Adenomatous Polyposis-Associated Desmoid Tumors

Desmoid tumors (DT) represent the second high risk of tumor in familial adenomatous polyposis (FAP) patients. Although FAP-associated DTs (FAP-DT) are caused by germline mutations in the adenomatous polyposis coli (APC) gene, extracolonic manifestations, sex, family history, genotype, and the ileal pouch anal anastomosis procedure are all linked to the development of DTs in FAP patients. Multidisciplinary management has replaced aggressive surgery as the preferred treatment of DTs. There is growing evidence to support the use of active surveillance strategy as first-line treatment for FAP-DT patients. Radiotherapy for intra-abdominal desmoids is now rarely used because of severe late toxicity. Pharmacotherapy, however, represents a promising future with the improvement of traditional cytotoxic drugs and the investigation of targeted drugs. Although nonsurgery treatment has been used widely nowadays, surgery remains the mainstay when symptomatic or life-threatening DTs are present. Further research will be needed for more optimal clinical practice.

Oral vinorelbine in young patients with desmoid-type fibromatosis

BACKGROUND

Desmoid-type fibromatosis are rare intermediate tumors in children and adolescents. Owing to local aggressiveness and relapse, systemic treatment for symptomatic advanced or progressive forms is recommended. Following promising results in adult patients, oral vinorelbine is investigated in young patients.

METHODS

A retrospective review of young patients (<25 years old) with advanced or progressive desmoid type fibromatosis treated with oral vinorelbine in eight large centers of the Société Française des Cancers de l'Enfant was performed. In addition to tumor assessment according to RECIST 1.1, pre-treatment and during-treatment imagery were reviewed centrally to assess tumor volume and estimate fibrosis score through the change in percentage in hypoT2 signal intensity.

RESULTS

From 2005 to 2020, 24 patients (median age 13.9 years [range, 1.0-23.0]) received oral vinorelbine. Median number of prior systemic lines of treatment was 1 (range, 0-2), mainly based on intravenous low dose methotrexate and vinblastine. Before vinorelbine initiation, all patients had a progressive disease: radiological for 19, radiological and clinical (pain) for three and only clinical for two. Oral vinorelbine was delivered for a median duration of 12 months (range, 1-42). The toxicity profile was favorable, with no grade 3-4 event. Overall response estimated on 23 evaluable patients according to RECIST 1.1 criteria was three partial responses (13%), 18 stabilization (78%) and two progressive disease (9%). Overall progression-free survival was 89.3% (95% confidential intervals 75.2-100) at 24 months. Four stable tumors according to standard RECIST criteria displayed a partial response with > 65% tumor volume reduction. Among 21 informative patients, the estimated fibrosis score decreased for 15 patients, was stable for four patients and increased for two patients.

CONCLUSION

Oral vinorelbine seems to be effective to control advanced or progressive desmoid type fibromatosis in young patients, with a well-tolerated profile. These results support testing this drug as first-line alone or in combination to improve response rate while preserving quality of life.

Understanding a mass in the paraspinal region: an anatomical approach

The paraspinal region encompasses all tissues around the spine. The regional anatomy is complex and includes the paraspinal muscles, spinal nerves, sympathetic chains, Batson's venous plexus and a rich arterial network. A wide variety of pathologies can occur in the paraspinal region, originating either from paraspinal soft tissues or the vertebral column. The most common paraspinal benign neoplasms include lipomas, fibroblastic tumours and benign peripheral nerve sheath tumours. Tumour-like masses such as haematomas, extramedullary haematopoiesis or abscesses should be considered in patients with suggestive medical histories. Malignant neoplasms are less frequent than benign processes and include liposarcomas and undifferentiated sarcomas. Secondary and primary spinal tumours may present as midline expansile soft tissue masses invading the adjacent paraspinal region. Knowledge of the anatomy of the paraspinal region is of major importance since it allows understanding of the complex locoregional tumour spread that can occur via many adipose corridors, haematogenous pathways and direct contact. Paraspinal tumours can extend into other anatomical regions, such as the retroperitoneum, pleura, posterior mediastinum, intercostal space or extradural neural axis compartment. Imaging plays a crucial role in formulating a hypothesis regarding the aetiology of the mass and tumour staging, which informs preoperative planning. Understanding the complex relationship between the different elements and the imaging features of common paraspinal masses is fundamental to achieving a correct diagnosis and adequate patient management. This review gives an overview of the anatomy of the paraspinal region and describes imaging features of the main tumours and tumour-like lesions that occur in the region.

Imaging of pediatric abdominal soft tissue tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper

This paper provides imaging recommendations for pediatric abdominal tumors that arise outside of the solid viscera. These tumors are rare in children and have been categorized in two groups: abdominal wall and peritoneal tumors (desmoid tumor and desmoplastic small round cell tumor) and tumors that arise from the gastrointestinal tract (gastrointestinal stromal tumor and gastrointestinal neuroendocrine tumor). Authors offer consensus recommendations for imaging assessment of these tumors at diagnosis, during follow-up, and when off-therapy.

Acute abdominal pain in women of reproductive age: keys to suggest a complication of endometriosis

Although endometriosis is a common gynecological condition in women of reproductive age, a complication of endometriosis is rarely considered as the differential diagnosis of acute abdominal pain in that context. However, acute events in women with endometriosis can represent life-threatening conditions, which require emergent treatment and often surgical management. Mass effect of endometriotic implants can give rise to obstructive complications, specifically occurring in the bowel or in the urinary tract, while inflammatory mediators released by ectopic endometrial tissue can lead to inflammation of the surrounding tissues or to superinfection of the endometriotic implants. Magnetic resonance imaging is the best imaging modality to reach the diagnosis of endometriosis, but an accurate diagnosis is possible on computed tomography, especially in the presence of stellar, mildly enhanced, infiltrative lesions in suggestive areas. The aim of this pictorial review is to provide an image-based overview of key findings for the diagnosis of acute abdominal complications of endometriosis.

Two synchronous desmoids tumours of the thoracic wall: A case report

INTRODUCTION AND IMPORTANCE

Desmoid tumour is a rare neoplasm that develops from the fascia and musculoaponeurotic tissue. These tumours tend to local invasion. Desmoid tumours are usually solitary. We present the first case of two synchronous desmoid tumours of the chest wall.

CASE PRESENTATION

A 56-year-old male with no medical history presented a painless chest wall mass. CT scan showed a deep soft tissue mass infiltrating the pectoralis major and minor muscles with an invasion of the subclavian and axillary pedicles and a second tumour infiltrating the latissimus dorsi muscle. MRI has allowed for a better study of these two masses, and a surgical biopsy confirmed the diagnosis of a desmoid tumour. The surgical resection was intra-tumoural for the anterior mass to preserve the axillary and subclavian pedicles, and the tumour resection was marginal for the posterior tumour. The postoperative course was uneventful, and an adjuvant therapy based on Imatinib was performed. The tumour residue was stabilized for two years follow-up.

CLINICAL DISCUSSION

Desmoid tumours are considered a locally aggressive disease. Ultrasound, CT scan, and MRI have different roles in their diagnosis. But pathological diagnosis is the "golden standard" diagnosis of desmoid tumours. The treatment of desmoid tumours is still not standardized. Surgery is the best primary treatment, but sometimes oncological resection may not be possible because of extension to the vital structure. Adjuvant therapy, like Imatinib, had demonstrated encouraging results.

CONCLUSION

For desmoid tumours with vital or noble structure invasion, intra-tumoural resection associated with adjuvant therapy demonstrated encouraging results.

Musculoskeletal Soft-tissue Masses

Evaluation of soft-tissue masses has become a common clinical practice indication for imaging with both ultrasound and MR imaging. We illustrate the ultrasonography and MR imaging appearances of soft-tissue masses based on the various categories, updates, and reclassifications of the 2020 World Health Organization classification.

Desmoid-type fibromatosis: imaging features and course

Desmoid-type fibromatosis (DF) is a soft tissue tumor characterized by infiltrative growth and a tendency toward local recurrence, while it exhibits self-limiting behavior and shows spontaneous regression. With its unpredictable behavior, a change in treatment strategies from initial surgery to nonsurgical management has been proposed, and active surveillance is currently widely chosen as the initial treatment strategy for DF. We reviewed the imaging features of DF regarding its clinical course, focusing on regression cases, postoperative cases, and imaging changes after systemic treatment.

Desmoid-type fibromatosis mimicking uterine fibroid invade the urinary bladder: A case report and literature review

OBJECTIVE

Desmoid fibromatosis (DF) is a rare, locally aggressive soft tissue tumor. Computed tomography (CT) and magnetic resonance imaging (MRI) play a critical role in the diagnosis of DF and in developing treatment plans. Currently, observation is the primary therapeutic option for a biopsy-confirmed DF. Here, we present a case of a DF that was misdiagnosed as uterine fibroid before surgery.

CASE REPORT

A 36-year-old woman presented with urinary frequency and a palpable lower abdominal mass, which was suspected as uterine fibroid based on sonography and CT. During surgery, an abdominal wall mass was found to be densely adherent to the bladder. Permanent pathology revealed that the tumor was desmoid-type fibromatosis.

CONCLUSION

Desmoid tumors often occur in the abdomen, abdominal wall, extremities, head, and neck. Abdominal wall DF involving the rectus abdominis muscles is most commonly observed. Conversely, desmoid tumors involving the bladder are less described. The review of similar cases reported since 1985 showed that partial cystectomy was primarily performed for complete resection.

Mimics of cancer in pregnancy

Pregnancy is a remarkable time of pronounced growth and development of the fetus. Benign pathologies outside of the uterus, including those containing hormonally responsive tissue which undergo physiologic changes and other incidentally identified lesions, may mimic malignancy on clinical evaluation and imaging. A detailed history and physical exam, ultrasound and non-contrast magnetic resonance imaging features and comparison with prior imaging if available may help to narrow the list of potential differential diagnoses. Follow-up imaging in the postpartum period is often vital to confirm benignity and, in some cases, sampling to confirm the diagnosis is necessary. This review will cover the clinical, pathological and multimodality imaging features of numerous potential mimickers of cancer in the setting of pregnancy organized by organ systems. The goal is to better equip abdominal radiologists to accurately identify benign disease and help guide further imaging or follow-up recommendations to avoid unnecessarily aggressive intervention and improve patient care.

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.

Abdominal wall endometriosis misdiagnosed as a desmoid tumor: A case report

Introduction

Abdominal wall masses have different aetiologies. Diagnosis includes desmoid tumors (DTs) and other benign and malignant lesions, among which abdominal wall endometriosis (AWE). Diagnosis is challenging if symptoms are aspecific, and the contribution of imaging may be weak. We present a case of AWE that according to clinical history and imaging was misdiagnosed as DT.

Presentation of case

A healthy 35-year-old female presented, 4 years after a cesarean delivery, a rapidly growing painless subumbilical mass within the right rectus abdominis muscle. Ultrasound and magnetic resonance imaging suspected a DT. The patient underwent complete resection of the mass and pathological examination revealed foci of endometriosis in the muscle. Patient's post-operative course was uneventful and at 18-month follow-up, no recurrence has been detected.

Discussion

The current case highlights differences in clinical presentation and imaging in case of AWE and DTs, underlining possible pitfalls in diagnosis. In young women with previous gynaecological abdominal surgery, AWE is the most likely disease when a mass in the region of the scar appears. Differential diagnosis is complex and rare entities like DTs should nevertheless be taken into consideration. A complete surgical resection with negative margins is considered the primary treatment for AWE and for selected DTs. Final pathology of the tumor can state the precise diagnosis.

Conclusion

Since AWE and DTs share similar clinical signs and aspecific imaging exams, both diseases should be considered in case of abdominal wall mass in female patients of childbearing age and history of uterine-related surgery.

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In presence of abdominal wall mass in reproductive women, diagnosis is challenging.

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Desmoid tumors and abdominal wall endometriosis can be misdiagnosed.

•

Both diseases share similar clinical signs and aspecific imaging exams.

•

Final pathology of the mass can state the precise diagnosis.

Imaging of the Vagina: Spectrum of Disease with Emphasis on MRI Appearance

The vagina is a median fibromuscular structure of the female reproductive system that extends from the vulva inferiorly to the uterine cervix superiorly. As most vaginal lesions are detected at gynecologic examination, imaging performed for nongynecologic indications can frequently cause concomitant vaginal pathologic conditions to be overlooked. The vagina is often underevaluated at routinely performed pelvic transvaginal US because of a narrow scan area and probe positioning. MRI has progressively become the imaging method of choice for vaginal pathologic conditions, as it provides excellent soft-tissue detail with unparalleled delineation of the complex pelvic floor anatomy and helps establish a diagnosis for most vaginal diseases. It is important that radiologists use a focused approach toward understanding and correctly recognizing different vaginal entities that may otherwise go unnoticed. In this case-based review, the authors discuss the key imaging features of wide-ranging vaginal pathologic conditions, with emphasis on appearance at MRI. Knowledge of vaginal anatomy and embryology is helpful in evaluating congenital anomalies at imaging. Often seen incidentally, vaginal inflammation can cause diagnostic confusion. Because of its central location in the pelvis, the vagina can form fistulas to the urinary bladder, colon, rectum, or anus. Vaginal masses can be neoplastic and nonneoplastic and include a myriad of benign and malignant conditions, some of which have characteristic imaging features. Therapeutic and nontherapeutic vaginal foreign bodies include pessaries, vaginal mesh, and packing that can be seen with or without associated complications. Online supplemental material is available for this article. ^©RSNA, 2021.

How embryology knowledge can help radiologists in the differential diagnosis of canal of Nuck pathologies

The Canal of Nuck (CN) is an anatomical structure which is often forgotten. It is the female equivalent of the male processus vaginalis and corresponds to a protrusion of parietal peritoneum that extends from the inguinal canal to labia majora. Radiologists rarely encounter patients with pathology of CN, especially in adult population. It is well known that CN diseases can occur in paediatric patient (especially younger than 5 years of age) and they are associated to high morbidity (for example ovarian hernia with high risk of incarceration and torsion). The aim of our work is to review embryology, anatomy and pathologies of the CN thanks to a multi modal approach-ultrasound (US), Computed Tomography (CT) and Magnetic Resonance imaging (MRI)-to make radiologists more aware of such conditions and guarantee a prompt and correct diagnosis not only in paediatric patients but also in the adult population.

The Role of Radiation Therapy for Symptomatic Desmoid Tumors

OPINION STATEMENT

Desmoid tumors have a variable clinical course that ranges from indolence or spontaneous regression to an aggressive pattern marked by local invasion. Up to half may remain stable or regress; watchful waiting is the preferred approach in the initial management of desmoid tumors. Symptomatic or progressive tumors or those that may affect adjacent critical structures require surgery, radiotherapy, or systemic therapy. Although radiotherapy effectively controls desmoid tumors in most cases, concerns regarding late toxicity exist. Definitive radiotherapy for macroscopic disease is indicated when a non-morbid complete surgical resection cannot be accomplished and provides similar control rates to surgery plus radiotherapy but avoids toxicity from combined-modality treatment (surgery and radiotherapy). Adjuvant radiotherapy can be considered for microscopically involved margins, particularly for recurrent cases or when a future recurrence may be challenging to treat. Large size, extremity site, and younger age are poor prognostic factors after radiotherapy. In the extremity, radiotherapy may have superior outcomes to surgery. Younger patients, especially children, are challenging to manage as they are at particular risk for late toxicity due to the number of potential years at risk. For patients under 20 years old, for whom a non-morbid complete resection is not possible, we recommend systemic therapy as the first line of treatment. Although the long-term efficacy of systemic therapy is unproven, this strategy allows additional time for growth and development prior to radiotherapy. In younger patients and those with axial desmoid tumors adjacent to critical organs, consideration should be given to using proton therapy as the dosimetric advantages may mitigate some of the toxicity associated with conventional radiotherapy.