Fibroblastic and Myofibroblastic Soft-Tissue Tumors: Imaging Spectrum and Radiologic-Pathologic Correlation.

Fibroblastic and myofibroblastic tumors are a variable group of neoplasms ranging from benign to malignant. These lesions may affect patients of any age group but are more frequently encountered in the pediatric population. Patient clinical presentation depends on the location, growth pattern, adjacent soft-tissue involvement, and pathologic behavior of these neoplasms. In the 2020 update to the World Health Organization (WHO) classification system, these tumors are classified on the basis of their distinct biologic behavior, histomorphologic characteristics, and molecular profiles into four tumor categories: (a) benign (eg, fibrous hamartoma of infancy, nodular fasciitis, proliferative fasciitis, fibroma of the tendon sheath, calcifying aponeurotic fibroma); (b) intermediate, locally aggressive (eg, desmoid fibromatosis); (c) intermediate, rarely metastasizing (eg, dermatofibrosarcoma protuberans, myxoinflammatory fibroblastic sarcoma, low-grade myofibroblastic sarcoma, infantile fibrosarcoma); and (d) malignant (eg, sclerosing epithelioid fibrosarcomas; low-grade fibromyxoid sarcoma; myxofibrosarcoma; fibrosarcoma, not otherwise specified). Detection of various components of solid tumors at imaging can help in prediction of the presence of corresponding histopathologic variations, thus influencing diagnosis, prognosis, and treatment planning. For example, lesions with a greater myxoid matrix or necrotic components tend to show higher signal intensity on T2-weighted MR images, whereas lesions with hypercellularity and dense internal collagen content display low signal intensity. In addition, understanding the radiologic-pathologic correlation of soft-tissue tumors can help to increase the accuracy of percutaneous biopsy and allow unnecessary interventions to be avoided. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Fasciitis ossificans: imaging features, histology, and differential diagnosis.

AIM: To describe the imaging features of fasciitis ossificans and its histopathological features. MATERIALS AND METHODS: Using a word search of existing pathology reports at the Mayo Clinic, six cases of fasciitis ossificans were identified. The clinical history, histology, and available imaging of the affected area were reviewed. RESULTS: Imaging consisted of radiographs, mammograms, ultrasound images, bone scintigraphs, computed tomography (CT), and magnetic resonance imaging (MRI) images. All cases demonstrated a soft-tissue mass. The characteristic MRI appearance was a T2 hyperintense enhancing mass with surrounding soft-tissue oedema. Peripheral calcifications were seen on radiographs, CT, and/or ultrasound. Histological sections showed distinct zonation, with nodular fasciitis-like zones of myofibroblastic proliferation, which merged with osteoblasts that rim the ill-defined trabeculae of woven bone and became continuous with the mature lamellar bone surrounded by a thin layer of compressed fibrous tissue. CONCLUSION: Imaging features of fasciitis ossificans are that of an enhancing soft-tissue mass located within a fascial plane with prominent surrounding oedema and mature peripheral calcification. Imaging and histology are that of myositis ossificans but occurring within the fascia. It is important that radiologists are aware of the diagnosis of fasciitis ossificans and appreciate its similarity to myositis ossificans. This is particularly important in anatomical locations with fascias but no muscle. Given the radiographic and histological overlap between these entities, nomenclature that encompasses both could be considered in the future.

Diffuse fasciitis with eosinophilia in boys: a case-based review.

Diffuse fasciitis with eosinophilia (EF) is a rare condition classified as a part of the connective tissue disorders. The clinical presentation of this condition can be diverse, however the main symptoms include symmetrical swelling and hardening of distal parts of limbs accompanied by peripheral eosinophilia. The diagnostic criteria are not specified. In inconclusions cases Magnetic Resonance Imaging (MRI) and skin to muscle biopsy may be useful. The pathogenesis and ethiology remain unknown, but extensive physical exertion, certain infectious factors, such as Borrelia burgdorferi, or medications may serve as a trigger. EF affects equally women and men, mainly in their middle age, however the disease can occur at any age. The standard therapy contents gluccocorticosteroids. As a second-line treatment, methotrexate is usually chosen. In this article we compare world reports of EF in paediatric patients with the cases of two adolescent male patients recently hospitalized in the Department of Paediatric Rheumatology.

Extremely rare occurrence of multiple cranial fasciitis: A case report.

Cranial fasciitis (CF) is a rare, rapidly growing, benign fibroproliferative lesion of the skull in the pediatric population. It is characterized by benign mesenchymal proliferation of spindle cells arranged as short, intersecting loose fascicles within a fibromyxoid stroma, and mostly appears as a single mass. A surgical excision with clear surgical margins is definitively curative for CF. Up to date only two cases with multiple CF have been reported in the literature. In this report, we describe a 1-year-old girl with multiple locations of CF, as the first case to be reported in the Turkish population. The radiological and morphological findings of our case were comparable with the observations of the two previous reports in the literature. Histopathological examination remains to be the gold-standard for differential diagnosis of CF, as the treatment of this lesion differs from other malignancies of the skull in the pediatric population.

Intravascular fasciitis of the scalp as a complication of ICP monitor placement: a case report and review of the literature.

BACKGROUND/IMPORTANCE: There are only 56 documented cases of intravascular fasciitis, a rare variant of nodular fasciitis. Of these cases, only 2 involved the scalp. This lesion is amenable to surgical resection, making it important to differentiate it from soft tissue malignancies of the scalp. CLINICAL PRESENTATION: We report an unusual case of intravascular fasciitis involving the scalp at the site of an intracranial pressure (ICP) monitor of a 13-year-old male patient. The lesion was surgically excised with no recurrence upon 1-month follow-up. CONCLUSION: Intravascular fasciitis is a benign, reactive proliferation of soft tissue that may arise at sites of prior trauma. It appears as a soft, painless, mobile lesion, and immunohistochemical studies are required to differentiate it from malignant lesions. The standard of care is surgical resection of the lesion.

Development of clinical and magnetic resonance imaging-based radiomics nomograms for the differentiation of nodular fasciitis from soft tissue sarcoma.

BACKGROUND: Accurate differentiation of nodular fasciitis (NF) from soft tissue sarcoma (STS) before surgery is essential for the subsequent diagnosis and treatment of patients. PURPOSE: To develop and evaluate radiomics nomograms based on clinical factors and magnetic resonance imaging (MRI) for the preoperative differentiation of NF from STS. MATERIAL AND METHODS: This retrospective study analyzed the MRI data of 27 patients with pathologically diagnosed NF and 58 patients with STS who were randomly divided into training (n = 62) and validation (n = 23) groups. Univariate and multivariate analyses were performed to identify the clinical factors and semantic features of MRI. Radiomics analysis was applied to fat-suppressed T1-weighted (T1W-FS) images, fat-suppressed T2-weighted (T2W-FS) images, and contrast-enhanced T1-weighted (CE-T1W) images. The radiomics nomograms incorporating the radiomics signatures, clinical factors, and semantic features of MRI were developed. ROC curves and AUCs were carried out to compare the performance of the clinical factors, radiomics signatures, and clinical radiomics nomograms. RESULTS: Tumor location, size, heterogeneous signal intensity on T2W-FS imaging, heterogeneous signal intensity on CE-T1W imaging, margin definitions on CE-T1W imaging, and septa were independent predictors for differentiating NF from STS (P < 0.05). The performance of the radiomics signatures based on T2W-FS imaging (AUC = 0.961) and CE-T1W imaging (AUC = 0.938) was better than that based on T1W-FS imaging (AUC = 0.833). The radiomics nomograms had AUCs of 0.949, which demonstrated good clinical utility and calibration. CONCLUSION: The non-invasive clinical radiomics nomograms exhibited good performance in the differentiation of NF from STS, and they have clinical application in the preoperative diagnosis of diseases.

Infantile Cranial Fasciitis: A Clinicopathologic Evaluation.

OBJECTIVE: To investigate the clinicopathologic features, immunophenotype, molecular genetic changes, and differential diagnosis of cranial fasciitis (CF). METHODS: The clinical manifestations, imaging, surgical technique, pathologic characteristics, special staining, and immunophenotype, as well as break-apart fluorescence in situ hybridization assay for USP6 of 19 CF cases were analyzed, retrospectively. RESULTS: The patients were 11 boys and 8 girls, aged 5 to 144 months, with a median age of 29 months. There were 5 cases (26.31%) in the temporal bone, 4 cases (21.05%) in the parietal bone, 3 cases (15.78%) in the occipital bone, 3 cases (15.78%) in the frontotemporal bone, 2 cases (10.52%) in the frontal bone, 1 case (5.26%) in the mastoid of middle ear, and 1 case (5.26%) in the external auditory canal. The main clinical manifestations were painless, with the presentation of masses that grew rapidly and frequently eroded the skull. There was no recurrence and no metastasis after the operation. Histologically, the lesion consists of spindle fibroblasts/myofibroblasts arranged in bundles, braided or atypical spokes. Mitotic figures could be seen, but not atypical forms. Immunohistochemical studies showed diffuse strong positive SMA and Vimentin in all CFs. These cells were negative for Calponin, Desmin, ß-catenin, S-100, and CD34. The ki-67 proliferation index was 5% to 10%. Ocin blue-PH2.5 staining showed blue-stained mucinous features in the stroma. The positive rate of USP6 gene rearrangement detected by fluorescence in situ hybridization assay was about 10.52%, and the positive rate was not related to age. All patients were observed for 2 to 124 months and showed no signs of recurrence or metastasis. CONCLUSIONS: In summary, CF was a benign pseudosarcomatous fasciitis that occurs in the skull of infants. Preoperative diagnosis and differential diagnosis were difficult. Computed tomography typing might be beneficial for imaging diagnosis, and pathologic examination might be the most reliable way to diagnose CF.

Ultrasound features and differential diagnosis for superficial nodular fasciitis.

BACKGROUND: Nodular fasciitis (NF) has nonspecific clinical manifestations and is often misdiagnosed as sarcoma. The investigations of imaging methods for NF were limited. OBJECTIVE: To analyze the ultrasound (US) features of NF, and to evaluate the diagnostic value of US for NF. MATERIALS AND METHODS: A total of 61 NF patients were recruited retrospectively, and 551 lesions in the subcutaneous fat layer were included for comparison. We evaluated the ultrasound features of the patients and divided the NF cases into three types. Chi-square test or Fisher exact test were conducted to detect the potential difference in the distributions of three types in the two groups. RESULTS: Among the 61 NF cases, 65.6% were in the upper extremities (n = 40). The proportion of type 1, 2, and 3 were 57.4%, 24.6%, and 18.0%, respectively. NF were significantly more likely locating in the upper extremities than the other soft tissue tumors (p < 0.001). Type 1 and type 2 of sonographic features were significantly more commonly observed in NF than other soft tissue tumors among the three types (p < 0.001). CONCLUSION: The type 1 and type 2 of US features can help to distinguish NF from other lesions. US has great potential to improve the diagnostic accuracy and reduce the unnecessary surgery.

Orbital nodular fasciitis in the pediatric population: a case report and review of the literature.

A 10-month-old female presented with a rapidly growing, painless mass in the right upper eyelid. Due to suspected malignancy, she underwent an urgent biopsy. Histopathological and immunohistochemical analyses revealed nodular fasciitis. Here, we describe the case and perform a literature review of orbital nodular fasciitis in the pediatric population.

Nodular fasciitis of the breast: the report of three cases.

BACKGROUND: Nodular Fasciitis is a benign fibroblastic proliferation in soft tissues, which mostly occurs in the upper extremities, trunk, head and neck region. It is rarely reported to occur in the breast. CASE PRESENTATION: Herein, we present sonograms of nodular fasciitis in the breast at different durations in three cases. In Case 1, we provided the longest follow-up time in all literatures. In Case 2 and Case 3, we provided the automated breast ultrasound finding of breast nodular fasciitis for the first time. CONCLUSION: Nodular Fasciitis shows clinical features and ultrasonography findings are similar to those of breast cancer. For superficially located breast lesions with a single and rapid growth, nodular fasciitis may be considered in the differential diagnosis of benign entities resembling malignant tumors on breast imaging.

Cranial fasciitis in children: clinicoradiology features and management.

BACKGROUND: Cranial fasciitis (CF) is a rare benign fibroproliferative lesion of the skull. To date, the summarized radiologic characteristics and the subtype of the disease have not been reported. our purpose was to summarize the characteristic clinicoradiology features and management of CF and to improve the knowledge of radiologists and clinicians. METHODS: We searched our institution's database and retrieved the clinical and radiologic data of CF patients confirmed by histopathological examination. The clinicoradiology features and management of CF were analysed retrospectively. RESULTS: A total of 14 CF patients were included. A total of 85.7% of the patients presented with a painless, firm, nonmobile and single mass. Tenderness and multiple masses were found in 14.3% of the patients. The mass was clearly increased in 2 patients and gradually increased in 5 patients in the short term. We divided these patients into three types based on the CT characteristics. The characteristic features of type I (9 patients) presented as an expansive and osteolytic bone destruction with a soft tissue mass. Type II (2 patients) presented as a scalp mass with mild erosion of the outer skull plate. Type III (3 patients) presented as a scalp mass without skull destruction. All patients underwent surgical resection. For type I patients, craniectomy and cranioplasty were performed. For type II patients, complete excision of the scalp mass with local skull curettage was performed. For type III patients, complete excision of the scalp mass was performed. There were no cases of recurrence after follow-up. CONCLUSIONS: CF usually presents as a painless, firm, nonmobile and single mass with a clear boundary. There are generally three types of MSCT findings: bone destruction with a soft tissue mass, a scalp mass with erosion of the skull and a scalp mass. Different management strategies should be utilized for the various types of CF.

[A Case of Breast Nodular Fasciitis Needed to Differentiate from Borderline Phyllodes Tumor].

A 28-year-old woman realized a left breast tumor. Mammography and ultrasonography revealed focal asymmetric density on the MI area(category 3)and a low-echoic 10 mm tumor with unclear boundaries. We performed an US-guided breast biopsy to confirm the diagnosis. The histopathological examination result suspected nodular fasciitis; however, borderline phyllodes tumor cannot be denied. Tumorectomy was performed under general anesthesia. The final histopathological examination revealed nodular fasciitis due to amplifying fibroblasts with irregular directions. Nodular fasciitis is a benign lesion and sometimes disappears spontaneously. Tumorectomy is often needed to confirm the diagnosis that cannot be identified by needle biopsy. We report a case of breast nodular fasciitis needed to differentiate from borderline phyllodes tumor.

The place of 18F FDG PET/CT in the management of patients with eosinophilic fasciitis: a case report.

Eosinophilic fasciitis is a rare connective tissue disease with a clinical presentation of scleroderma-like disease. We report a case of a 36-year-old female patient with a 6-month history of progressive stiffness involving her forearms and legs with joint pain. Laboratory examinations showed hypereosinophilia and elevated C-reactive protein. 18F FDG PET/CT showed diffuse and symmetrical increased uptake in the fasciae of the upper and lower limbs, sparing both muscles and fat tissues. Guided biopsy and histologic examination confirmed the diagnosis of eosinophilic fasciitis. 18F FDG PET/CT is of great help in the diagnosis of eosinophilic fasciitis, as it can guide the biopsy where FDG uptake is strongest and also help rule out possible associated neoplasms.

Response of eosinophilic fasciitis associated with Waldenström macroglobulinemia to rituximab.

Eosinophilic fasciitis (EF) and generalized morphea (GM) are rare and difficult-to-treat sclerosing skin diseases which may occur in association with hematologic disorders. We present a 66-year-old man with EF and associated Waldenström macroglobulinemia who received combination therapy with rituximab (375mg/m2 every other week, gradually extended to every eight weeks), prednisolone (1.25-30mg/d), and methotrexate (7.5-15mg/w). Three months after rituximab initiation, his skin condition improved steadily accompanied by a significant improvement in joint mobility with only mild and transitory flares (observation period: 59 months under treatment with rituximab). To date, there are five case reports on rituximab treatment of EF/GM with an association to hypergammaglobulinemia in three of those cases. Therapy effected significant improvement in four patients. Our case adds to the hitherto limited evidence that rituximab may be a promising therapeutic strategy for EF/GM in association with hypergammaglobulinemia.

An MRI study of immune checkpoint inhibitor-induced musculoskeletal manifestations myofasciitis is the prominent imaging finding.

OBJECTIVE: To assess: (i) the prevalence, and clinical and imaging characteristics of immune checkpoint inhibitor (ICI)-induced musculoskeletal immune-related adverse events (ir-AEs) in a prospective manner and (ii) whether serum levels of cytokines associated with the Th1/Th2/Th17 response are differentially expressed in patients with and without musculoskeletal Ir-AEs. METHODS: All patients treated with ICI who developed musculoskeletal manifestations were referred to the Rheumatology Department, and an MRI of the involved area(s) was performed. RESULTS: During the study period, a total of 130 patients were treated with ICIs. Of these, 10 (7.7%) developed ICI-induced Ir-AEs. The median time from ICI treatment since development of symptoms was 2.5 months. Three different patterns of musculoskeletal manifestations were found: (i) prominent joint involvement (n = 3); (ii) prominent 'periarticular' involvement (n = 4). These patients had diffuse swelling of the hands, feet or knees. MRI depicted mild synovitis with more prominent myositis and/or fasciitis in the surrounding tissues in all cases; (iii) myofasciitis (n = 3). Clinically, these patients presented with pain in the knee(s)/thigh(s), whereas MRI depicted myofasciitis of the surrounding muscles. Patients with musculoskeletal ir-AEs had significantly higher oncologic response rates compared with patients not exhibiting musculoskeletal ir-AEs (50% vs 12.5%, respectively, P = 0.0016). Cytokine levels associated with a Th1/Th2/Th17 response were similar between patients with and without musculoskeletal ir-AEs. Overall, symptoms were mild/moderate and responded well to treatment, with no need for ICI discontinuation. CONCLUSION: In our cohort, ICI-induced musculoskeletal manifestations developed in 7.7% of patients. Imaging evidence of myofasciitis was found in most patients, indicating that the muscle/fascia is more frequently involved than the synovium.

A Rare Case of Intravascular Fasciitis Misdiagnosed as Deep Venous Thrombosis.

PURPOSE: This case aimed to explore the clinical, histological, and immunohistochemical features of intravascular fasciitis (IVF) that involve a large blood vessel. CASE REPORT: A 27-year-old man presented with swelling and pain of the left lower limb for 5 days. The report of Doppler ultrasonography confirmed deep venous thrombosis (DVT) in the lower left limb (acute phase). However, laboratory value for the presence of D-dimer was negative. Thus, we performed an ascending venography and identified a mass in the common femoral vein. At operation, an incision of the left common femoral vein was made, and the mass was completely resected. CONCLUSIONS: The situation of IVF that grew in a large vein is extremely rare and can easily be misdiagnosed as DVT. The presence of D-dimer is important for a differential diagnosis. Ascending venography can be applied in making an accurate diagnosis.

Soft-Tissue Tumors of the Hand-Imaging Features.

Imaging studies of the hands and fingers are common, and radiologists are generally comfortable with traumatic and degenerative conditions which arise frequently in daily practice. However, a variety of common and uncommon soft-tissue tumors also occur in the hand, the appropriate diagnosis of which can be a source of confusion for both clinicians and radiologists. These lesions often have overlapping imaging characteristics; however, a structured approach can help provide a focused differential diagnosis and impact further workup and management. We discuss several such tumors, categorizing them as cystic-appearing, noncystic masses along tendons and aponeuroses, adipocytic tumors, vascular lesions, and miscellaneous lesions with imaging features that can aid diagnosis.

Case 272: Decubital Ischemic Fasciitis.

HistoryA 92-year-old bedridden woman presented to the emergency department from an assisted living facility with fever, cough, and swelling over the right lateral hip. She had baseline dementia and frailty and had been bedridden for 4 years. She did not have any recent falls or history of trauma at the site of swelling. She had a history of diffuse large B-cell lymphoma that had been diagnosed and treated 7 years ago, and thoracoabdominal CT at last follow-up 3 years ago did not show any recurrence. Physical examination findings were unremarkable except for a painful hard and fixed mass measuring approximately 5 × 5 × 10 cm (in the transverse, anteroposterior, and craniocaudal directions, respectively) located at the right lateral superior thigh. The overlying skin was intact, without any color changes. Pertinent blood test results showed an increased white blood cell count of 13,000/µL (13 × 109/L) (normal range, 3700-11,000/µL [3.7-11 × 109/L]). The remaining hematologic and biochemical test results were normal. Abdominal and pelvic CT performed at presentation did not show any abnormal lymph nodes. Because chest radiography showed consolidation in addition to typical clinical picture, the patient was diagnosed with pneumonia and underwent antibiotic treatment for 3 weeks. US and Doppler US of the mass were performed. MRI was not performed because the patient had a pacemaker; instead, CT of the lower extremity was performed.

Distinguishing necrotizing from non-necrotizing fasciitis: a new predictive scoring integrating MRI in the LRINEC score.

OBJECTIVES: To develop and validate a scoring system integrating MRI and laboratory findings to differentiate necrotizing fasciitis (NF) from non-necrotizing fasciitis (non-NF). METHODS: This retrospective study included 144 subjects who underwent surgery in one of three tertiary referral centers for NF or cellulitis with non-NF. The development cohort consisted of 96 subjects (NF = 47; non-NF = 49) from one center, and the validation cohort consisted of 48 subjects (NF = 23; cellulitis with non-NF = 25) from two different centers. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) scoring system and five MRI findings (thickening of the intermuscular deep fascia ≥ 3 mm, extensive involvement of the deep fascia, multi-compartmental involvement in one extremity, presence of gas, and contrast-enhancement pattern) were included in univariate and multivariate logistic regression analysis to identify independent predictors of NF. An additive scoring system was developed using the coefficients of the final regression model. Model performance was assessed for discrimination and calibration. The scoring system was externally validated. RESULT: The final scoring system consisted of three variables: thickening of the deep fascia ≥ 3 mm, multi-compartmental involvement, and LRINEC score. The new predictive model showed improved performance (area under the receiver operating characteristic curve [AUC], 0.862; positive and negative predictive values, 82% and 79%, respectively), compared with the LRINEC score alone (0.814, 77% and 67%, respectively). The model also showed good discrimination with the external validation dataset (AUC, 0.933). CONCLUSIONS: Differentiation of NF from severe cellulitis with non-NF can be achieved with the new predictive scoring system. KEY POINTS: • The new predictive scoring system integrating two MRI findings with the LRINEC score can help in the differentiation of necrotizing fasciitis from severe cellulitis with non-necrotizing fasciitis. • Thickening of the deep fascia ≥ 3 mm and multi-compartmental involvement were the most important MRI findings for the differentiation.

Diagnostic Imaging of Inflammatory Myopathies: New Concepts and a Radiological Approach.

PURPOSE OF REVIEW: The purpose of this review article is to highlight the current role of diagnostic imaging in the assessment of inflammatory myopathies. RECENT FINDINGS: Recent research demonstrates that imaging plays an important role in evaluating patients with symptoms of an inflammatory myopathy. In general, MRI is the pivotal imaging modality for assessing inflammatory myopathies, revealing precise anatomic details because of changes in the signal intensity of the muscles. Whole-body MR imaging has become increasingly important over the last several years. US is also a valuable imaging modality for scanning muscles. Together with the clinical history, familiarity with the imaging features of inflammatory myopathies is essential for formulating an accurate diagnosis.