Desmoid-Type Fibromatosis of the Thorax: CT, MRI, and FDG PET Characteristics in a Large Series From a Tertiary Referral Center

Annotating the Role of 18F-FDG PET/CT in Fibromatoses: A Benign Masquerader of Malignancies-Is It Really an Advantageous Tool?

Fibromatoses are a heterogeneous group of benign proliferating fibroblasts and myofibroblasts which have a high predilection for recurrence and local invasion, especially deep fibromatoses or desmoid fibromatosis. 18F-FDG PET/CT, the workhorse of oncological imaging in nuclear medicine, can be employed to figure out the nature and aggressiveness of the lesions and various sites of involvement and to monitor treatment response to systemic therapies like tyrosine kinase inhibitors in case of deep or desmoid fibromatoses which is shown in the current research work.

PET imaging characteristics of neuromuscular choristoma and associated desmoid-type fibromatosis

BACKGROUND

Neuromuscular choristoma (NMC) is a rare peripheral nerve lesion characterized by abnormal presence of muscle within nerve. Associated desmoid-type fibromatosis (NMC-DTF) often develops. We report ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET) characteristics of NMC and NMC-DTF and propose that increased FDG activity within NMCs may be associated with subclinical NMC-DTF or NMC-DTF "precursor" tissue.

METHODS

Our institutional database was searched for all NMC cases. Inclusion criteria were 1) confirmed diagnosis of NMC with or without biopsy, and 2) available PET and MRI studies. PET data included SUVmax and SUVmean of NMCs, contralateral limb normal skeletal muscle and unaffected nerves, and SUVmax of NMC-DTF if present. SUV values were compared using paired t-test. A p value of < 0.05 was considered statistically significant.

RESULTS

Our cohort consisted of 9 patients with NMC, 8 cases involving sciatic nerve and 1 of brachial plexus. On PET imaging, all NMC-affected nerve segments showed significantly higher FDG uptake (SUVmax/mean) compared to both contralateral normal nerve and normal skeletal muscle (all P < 0.05). Similar to sporadic DTF, NMC-DTF was highly FDG-avid (average SUVmax of 4.2). SUVmax in NMC with or without concurrent NMC-DTF did not differ (p = 0.76). Within NMC-affected nerve segment, FDG activity was relatively higher in areas with low T1/T2 MR signal.

CONCLUSION

All NMCs were more FDG avid compared to both normal skeletal muscle and contralateral unaffected nerve, arguing against the presence of heterotopic muscle in NMC as the source of FDG avidity. FDG avidity within NMC may reflect subclinical NMC-DTF or a precursor lesion, as NMC-DTF are highly FDG-avid, and the highest regions of FDG avidity in NMC occurred in regions with MR characteristics associated with NMC-DTF (i.e., lower T1/T2 signal). We believe that the integration of FDG PET with serial MR imaging in patient follow up will clarify its utility in both detection and surveillance of NMC-DTF.

An accidental finding of a retroperitoneal desmoid tumor: case report and review of the literature

Retroperitoneal desmoid-type fibromatosis is a rare benign mesenchymal neoplasm that develops as a result of fibroblastic proliferation within the musculoaponeurotic stroma. The authors present the case of a 41-year-old male patient who was referred for a retroperitoneal neoplasm. A mesenteric mass core biopsy was done, and it revealed a low-grade spindle cell lesion consistent with desmoid fibromatosis.

Large Intrathoracic Desmoid Tumor and Re-Expansion Pulmonary Edema: Case Report and Review of the Literature

Re-expansion pulmonary edema is a potentially life-threatening situation following thoracic surgery of a compromised lung. We report the case of a 24-year-old female scheduled for a resection of a large intrathoracic desmoid tumor that presented with re-expansion pulmonary edema at the conclusion of her surgery and discuss the clinical presentation, mechanism and predictors of this entity and review similar cases reported in the literature.

Gas-containing mesenteric desmoid-type fibromatosis: A case report

RATIONALE

Desmoid-type fibromatosis is a rare benign mesenchymal neoplasm. Only 8% of desmoid-type fibromatosis develops in the abdominal cavity. The mesentery is seldom affected and gastrointestinal stromal tumors need to be considered in the differential diagnosis, particularly when imaging examination shows a tumor containing gases in the abdominal cavity. Only a few cases of gas-containing mesenteric desmoid-type fibromatosis have been reported in the literature.

PATIENT CONCERNS

A 69-year-old male patient presented with hematochezia and intermittent upper abdominal pain.

DIAGNOSIS

Contrast-enhanced computed tomography revealed a 3.9 × 3.6 cm gas-containing mass infiltrating the third portion of the duodenum. The tumor was heterogeneous, with cysts and air bubbles. It showed heterogeneous weak-to-mild enhancement in the solid part. Postoperative pathological examination confirmed a final diagnosis of mesenteric desmoid-type fibromatosis.

INTERVENTIONS

The patient underwent surgical resection of intra-abdominal lesion.

OUTCOMES

No evidence of local recurrence was noted during the 6 months of follow-up.

LESSONS

Accurate preoperative diagnosis is difficult for an intra-abdominal gas-containing mass on computed tomography scan. The appearance of spiculated infiltrative margin suggests the diagnosis of desmoid-type fibromatosis. Further investigation of imaging evidence and treatment methods is necessary.

Intraabdominal sporadic desmoid tumors and inflammation: an updated literature review and presentation and insights on pathogenesis of synchronous sporadic mesenteric desmoid tumors occurring after surgery for necrotizing pancreatitis

Sporadic intra-abdominal desmoid tumors are rare and known to potentially occur after trauma including previous surgery, although knowledge of the underlying pathogenetic mechanism is still limited. We reviewed the recent literature on sporadic intraabdominal desmoids and inflammation as we investigated the mutational and epigenetic makeup of a case of multiple synchronous mesenterial desmoids occurring after necrotizing pancreatitis. A 62-year-old man had four mesenteric masses up to 4.8 cm diameter detected on CT eighteen months after laparotomy for peripancreatic collections from necrotizing pancreatitis. All tumors were excised and diagnosed as mesenteric desmoids. DNA from peripheral blood was tested for a multigene panel. The tumour DNA was screened for three most frequent β-catenin gene mutations T41A, S45F and S45P. Expression levels of miR-21-3p and miR-197-3-p were compared between the desmoid tumors and other wild-type sporadic desmoids. The T41A CTNNB1 mutation was present in all four desmoid tumors. miR-21-3p and miR-197-3p were respectively upregulated and down-regulated in the mutated sporadic mesenteric desmoids, with respect to wild-type lesions. The patient is free from recurrence 34 months post-surgery. The literature review did not show similar studies. To our knowledge, this is the first study to interrogate genetic and epigenetic signature of multiple intraabdominal desmoids to investigate potential association with abdominal inflammation following surgery for necrotizing pancreatitis. We found mutational and epigenetic features that hint at potential activation of inflammation pathways within the desmoid tumor.

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.

Misdiagnosed desmoid fibromatosis of the chest wall presenting in emergency like as recurrence of post-traumatic hematoma: A case report and review of the literature

Introduction and importance

Desmoid Fibromatosis (DF) represents a rare neoplasm developing from fascial and musculoaponeurotic structures. Preoperative diagnosis of DF is a challenge because of its rarity and nonspecific presentation. Imaging may be helpful for determining the correct diagnosis. Currently there are different clinical treatments of DF including surgical treatment, drug treatment and radiotherapy.

Case presentation

A 43-year-old Caucasian male presented to the Emergency Department with a 6-month history of recurrence of post-traumatic chest wall hematoma. Physical examination revealed a partially solid, painless mass on the right anterior chest wall. Laboratory tests reported and neutrophilic leukocytosis. Thoracic contrast-enhanced computed tomography showed a smooth contour, heterogeneous and hypodense subcutaneous soft tissue mass anterior to the right pectoral muscles and to the right 4th–7th rib. The patient underwent surgery: a solid suprafascial neoplasm was completely excised. The postoperative course of the patient was uneventful.

Clinical discussion

DF is a soft tissue neoplasm with a tendency for local invasion and recurrence. The course of DF cannot be predicted, being fatal if DF infiltrates vital structures. Diagnosis of DF is difficult and imaging may be helpful for determining the correct diagnosis. Currently the treatment for DF has shifted from surgery (post-operative recurrence rates of 20%–70%) to conservative therapy including watchful waiting.

Conclusion

DF is a myofibroblastic proliferative soft tissue tumor and classified as an intermediate malignancy. Preoperative diagnosis of DF needs a high index of suspicion and is facilitated by imaging. Surgery, among different treatments, represents a potentially curative treatment of DF.

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Desmoid Fibromatosis (DF) represents a rare neoplasm developing from fascial and musculoaponeurotic structures.

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The central biologic event in the DF formation is an alteration in the Wnt/β-catenin pathway.

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Diagnosis of DF is a challenge because of the absence of specific clinical presentation, pathognomonic radiographic and laboratory findings.

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Surgery, among different treatments, represents a potentially curative treatment of DF.

Surgical Management of a Giant Desmoid Fibromatosis of Abdominal Wall With Vessels Invasion in a Young Man: A Case Report and Review of the Literature

Background

Desmoid fibromatosis (DF) is a rare clonal proliferation of fibroblasts and myofibroblasts. It develops in the connective tissues and does not metastasize but may infiltrate adjacent structures. Because of the rarity of these tumors and the unpredictable natural history of the disease, well-defined and precise guidelines of the optimal treatment for DF have not been formulated.

Case Presentation

Here, we present a giant abdominal DF that invaded the right spermatic cord and iliac vessels. The lesion was excised with external iliac artery dissection; however, the vein was sacrificed. The abdominal wall defect was then repaired with a polypropylene mesh. The lesional cells are positive for β-catenin.

Conclusions

In the past decades, there has been a change in the treatment of DF. The “wait and see” policy has been considered initially in most cases. Surgical intervention remains a valid option for symptomatic lesions. The optimal regimes of the tumor should not take the risk of making the patient more symptomatic than the lesion itself.

Mesenchymal Tumors of the Mediastinum: An Update on Diagnostic Approach

Mesenchymal tumors of the mediastinum are a heterogenous group of rare tumors with divergent lineages. Mediastinal mesenchymal tumors are diagnostically challenging due to their diversity and morphologic overlap with nonmesenchymal lesions arising in the mediastinum. Accurate histologic diagnosis is critical for appropriate patient management and prognostication. Many mediastinal mesenchymal tumors affect distinct age groups or occur at specific mediastinal compartments. Neurogenic tumors, liposarcoma, solitary fibrous tumor, and synovial sarcoma are common mesenchymal tumors in the mediastinum. Herein, we provide an update on the diagnostic approach to mediastinal mesenchymal tumors and a review of the histologic features and differential diagnosis of common benign and malignant mesenchymal tumors of the mediastinum.

Imaging of Abdominal Wall Masses, Masslike Lesions, and Diffuse Processes

Abdominal wall masses, masslike lesions, and diffuse processes are common and often incidental findings at cross-sectional imaging. Distinguishing among these types of masses on the basis of imaging features alone can be challenging. The authors present a diagnostic algorithm that may help in distinguishing different types of abdominal wall masses accurately. Hernias may mimic discrete masses at clinical examination, and imaging is often ordered for evaluation of a possible abdominal wall mass. Once a discrete mass is confirmed to be present, the next step is to determine if it is a fat-containing, cystic, or solid mass. The most common fat-containing masses are lipomas. Fluid or cystic masses include postoperative abscesses, seromas, and rectus sheath hematomas. Solid masses are the most common abdominal wall masses and include desmoid tumors, sarcomas, endometriomas, and metastases. Multiple masses and other diffuse abdominal wall processes are often manifestations of an underlying condition or insult. The most frequently found diffuse processes are multiple injection granulomas from administration of subcutaneous medication. This article offers an algorithmic approach to characterizing abdominal wall masses on the basis of their composition and reviews abdominal wall diffuse processes. Online supplemental material is available for this article. ^©RSNA, 2020.

Value of imaging findings in predicting post-operative recurrence of desmoid-type fibromatosis

Desmoid-type fibromatosis is a rare type of soft-tissue tumor originating from connective tissue of the fascia or aponeurosis, which exhibits aggressive growth, high likelihood of relapse and less frequent distant metastasis. The present study aimed to predict the recurrence rate and time by retrospectively analyzing the clinical data (sex, age and recurrence time), imaging findings [tumor location, maximum diameter, border, computed tomography (CT) enhancement ratio, magnetic resonance enhancement ratio and T2 signal ratio] and pathological features (Ki-67 and microscopic margin) in a total of 102 cases of pathologically confirmed desmoid-type fibromatosis. The risk ratio of each factor was calculated using the Cox proportional hazards regression model and the cumulative recurrence-free survival rate was determined using the Kaplan-Meier method and the log-rank test. The cohort comprised of 73 females and 29 males, with mean age of 32.86±12.64 years (range, 6–78 years). The 1-year and 2-year recurrence rate was 31 and 54%, respectively. The median age at recurrence was 29 years. Univariate analysis indicated that sex, maximum tumor diameter, CT enhancement ratio and Ki-67 had a significant effect on the recurrence time. Furthermore, multivariate analysis revealed that sex, maximum tumor diameter, Ki-67 and T2 signal ratio were independently associated with the time of recurrence, and the risk ratios were 0.424, 1.100, 1.084 and 1.268, respectively. Therefore, in male patients with a larger maximum tumor diameter, positivity for Ki-67 and a higher T2 signal ratio, desmoid-type fibromatosis was more likely to recur after surgery.

Current Update on Desmoid Fibromatosis

OBJECTIVE

The purpose of this article is to review the etiopathogenesis, molecular cytogenetics, histopathology, clinical features, and multimodality imaging features of desmoid fibromatosis. Recent advances in the management of desmoid fibromatosis will also be discussed.

CONCLUSIONS

Desmoid fibromatosis is a rare soft tissue neoplasm with a high incidence of local recurrence. Imaging plays an important role in the diagnosis and management of this disease.

A Desmoid Tumor Involving the Subscapularis Muscle: A Case Report

CASE

A 31-year-old woman developed worsening pain and paresthesia in the neck, shoulder, and arm over a period of 6 years. Magnetic resonance imaging revealed a soft-tissue mass in the subscapular region, with likely involvement of the scapula and the subscapularis muscle. The mass was resected, and the final histologic diagnosis was desmoid-type fibromatosis.

CONCLUSION

Desmoid tumors with subscapularis muscle involvement are exceedingly rare. Although limited range of motion is the more common presentation for these tumors, this case demonstrates that desmoid tumors may present with primarily neurologic symptoms.

Multimodal radiological imaging of collagenous fibroma arising from the subacromial region in a patient with osteosarcoma: A case report

Collagenous fibroma arising from the subacromial region is extremely rare. It is important to distinguish collagenous fibroma from other fibrous tumors including desmoid tumors, to differentiate between the prognoses and management strategies, including surgical treatment. The present case report describes the case of a 42-year-old man with a collagenous fibroma of the subacromial region. He received a follow-up examination following treatment for osteosarcoma. Positron emission tomography (PET) scans used to assess for metastatic lesions indicated uptake in his left shoulder. The maximum standardized uptake value was 2.4. Magnetic resonance imaging demonstrated iso-intensity to muscle on T1-weighted images and iso-intensity with slightly high intensity on T2-weighted images. Post-contrast fat-suppressed magnetic resonance images indicated slightly heterogeneous enhancement of the lesion. There were no notable results from X-rays, bone scintigraphy and thallium-201 scintigraphy. Histological examination revealed collagenous fibroma. To the best of our knowledge, the present case is only the second incidence of collagenous fibroma arising from the subacromial region, and the first description of thallium-201 scintigraphy and PET scans in collagenous fibroma. The multimodal radiological data of this case may be useful for assisting in the differentiation of fibrous tumor types, including collagenous fibroma.

Desmoid Fibromatosis Mimicking Metastatic Recurrence After Pancreatectomy for Pancreatic Adenocarcinoma

Desmoid fibromatosis is a rare, neoplastic tumor known for its aggressive local invasion and recurrence after surgery. Tumors can occur sporadically or associated with familial adenomatous polyposis. We present 3 cases of desmoid fibromatosis postpancreatectomy for pancreatic adenocarcinoma. All cases occurred within 3 years of diagnosis of pancreatic cancer, with subsequent extensive diagnostic work-up to rule out metastatic disease. No relationship between pancreatic cancer and desmoid fibromatosis is documented in the literature, with a postulated connection via mutations on the Wnt/APC/Beta-catenin pathway.

Musculoskeletal Pitfalls on Fluorodeoxyglucose F 18 PET-Computed Tomography: Pictorial Review

A wide range of musculoskeletal processes can demonstrate increased uptake on PET-computed tomography (CT) with fluorodeoxyglucose (FDG) F 18, including reactive, benign neoplastic, inflammatory, traumatic, posttreatment, and arthritic conditions that may mimic malignancy. In addition, physiologic causes of increased FDG uptake such as asymmetric muscle use and presence of brown fat can lead to increased FDG uptake and potential false-positive results. This article presents various case examples of non-malignant musculoskeletal hypermetabolism on 18F-FDG PET-CT and describes useful tools to avoid the potential pitfall of misinterpreting these as malignancy.

Use of 18F-FDG-PET/CT for Retroperitoneal/Intra-Abdominal Soft Tissue Sarcomas

Rationale

To assess the diagnostic value of 18F-FDG-PET/CT for different retroperitoneal soft tissue sarcomas (STS) and other similar tumors. To analyze the predictive value of 18F-FDG-PET/CT for histological grade and main prognostic factors.

Methods

195 patients with 44 different diseases have been included. Relationship between SUVmax, Clinical, pathological, and prognostic information has been analyzed.

Results

Malignant tumors do not show higher SUVmax than benign ones (P=0.443). We divided all 44 different diseases into two groups; SUVmax of group 1 is significantly higher than group 2 (P ≤ 0.001). The ROC curve suggests 4.35 is the cutoff value to distinguish groups 1 and 2 (sensitivity = 0.789; specificity = 0.736). SUVmax correlates with Ki-67 index, mitotic count, vascular resection, histological grade, and recurrent STS without considering pathological diagnosis (P=0.001, P=0.012, P=0.002, P ≤ 0.001, and  P=0.037, resp.).

Conclusion

18F-FDG-PET/CT cannot simply distinguish malignant and benign tumors in retroperitoneal/intra-abdominal cavity; however, the SUVmax of malignant tumors, inflammatory pseudotumor, and PPGL group is higher than the SUVmax of benign tumors, lymph node metastasis, hematoma, and low malignant STS group. Guidance of "SUVmax location" may be helpful for biopsy and pathology dissection.

Fibromatosis Associated With Neuromuscular Choristoma: Evaluation by FDG PET/CT

Neuromuscular choristoma (NMC) is a rare benign peripheral nerve lesion consisting of mature skeletal muscle fibers admixed with nerve fascicles. Aggressive fibromatosis frequently develops in association with NMC, often after surgery or biopsy, but the exact pathogenesis is not known. We present a case of NMC complicated by aggressive fibromatosis evaluated by F-FDG PET/CT and examine the relationship of metabolic activity and MRI signal characteristics.

A Mesenteric Desmoid Tumor with Rapid Progression

We herein report the case of a rapidly progressive sporadic mesenteric desmoid tumor (DT). A 62-year-old woman presented with a 4-cm-diameter palpable mass in the left supraumbilical area. The mass showed an ill-defined margin with heterogeneous delayed enhancement on computed tomography and heterogeneous high intensity on T2-weighted magnetic resonance imaging. Sixteen months after the initial observation, the mass had grown in size, reaching 13 cm in diameter. The resected mass was histologically confirmed as a DT of the mesentery. Since DT often has an unpredictable clinical course, clinicians should bear in mind the need for imaging follow-up.