Conventional and contrast-enhanced ultrasound in the differential diagnosis of recurrent dermatofibrosarcoma protuberans and postoperative scar.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) has a high recurrence rate after resection. Because of the lack of specific manifestations, recurrent DFSP is easily misdiagnosed as post-resection scar. A few series have reported ultrasound findings of recurrent DFSP; moreover, the usefulness of contrast-enhanced ultrasound in differentiating recurrent DFSP has not been studied. OBJECTIVE: We investigated conventional and contrast-enhanced ultrasound in the differential diagnosis of recurrent DFSP and post-resection scar. METHODS: We retrospectively evaluated the findings of conventional and contrast-enhanced ultrasound in 34 cases of recurrent DFSP and 38 postoperative scars examined between January 2018 and December 2022. RESULTS: The depth and vascular density of recurrent DFSP were greater than those of postoperative scars (P < 0.05). On gray-scale ultrasound, recurrent DFSP lesions were more commonly irregular, heterogeneous, and hypoechoic, with finger-like projections and ill-defined borders. Postoperative scar was more likely to appear as hypoechoic and homogeneous with well-defined borders (P < 0.05). On color Doppler ultrasound, recurrent DFSP was more likely to feature rich arterial and venous blood flow, and postoperative scar was more likely to display poor blood flow (P < 0.05). On contrast-enhanced ultrasound, recurrent DFSP was more likely to feature heterogeneous hyper-enhancement, and postoperative scar was more likely to display homogeneous iso-enhancement (P < 0.05). Recurrent DFSP presented a higher peak and sharpness than postoperative scar (P < 0.05). CONCLUSION: Conventional and contrast-enhanced ultrasound produced distinct features of recurrent DFSP and post-resection scar, which could improve the accuracy of differential diagnosis.

Integrating vascularity into the pattern classification of pilomatricomas on ultrasound provides a more competent approach for discriminative evaluation.

BACKGROUND: Pilomatricoma has various manifestations on color Doppler ultrasound, and a differential diagnosis is challenging. The objective of this study was to investigate which characteristics of skin lesions on color Doppler ultrasound are effective in distinguishing pilomatricoma from epidermoid cyst and dermatofibrosarcoma protuberans. MATERIALS AND METHODS: Records of patients with pilomatricomas (n = 63), epidermoid cysts (n = 76), and dermatofibrosarcoma protuberans (n = 19) who underwent color Doppler ultrasound evaluation and surgical excision were reviewed. The anatomical distribution and color Doppler ultrasound characteristics of these lesions were analyzed. The 63 pilomatricomas were categorized into five types based on their color Doppler ultrasound characteristics, and the roles of these five types in the differential diagnosis of the aforementioned diseases were studied. RESULTS: Pilomatricomas, epidermoid cysts, and dermatofibrosarcoma protuberans exhibited some similar characteristics. Dominantly markedly hyperechoic or hyperechoic appearance, posterior acoustic shadowing, and the presence of vascularity were the major characteristics of pilomatricomas. The pilomatricomas could be categorized into five types, with type II having a diagnostic performance of sensitivity of 65.08%, specificity of 98.95%, area under the receiver operating characteristic curve (AUC) of 0.743, positive predictive value of 97.62%, and negative predictive value of 81.03% for the diagnosis of the aforementioned skin diseases. CONCLUSION: A combination of dominantly markedly hyperechoic or hyperechoic appearance, posterior acoustic shadowing, and the presence of vascularity exhibits higher diagnostic performance for the differential diagnosis of pilomatricomas, epidermoid cysts, and dermatofibrosarcoma protuberans.

Different sonographic presentations of dermatofibrosarcoma protuberans.

BACKROUND: Dermatofibrosarcoma protuberans (DFSP) is a low-grade spindle cell sarcoma of fibroblastic origin. This tumor originates in the dermis and infiltrates the subcutaneous tissue. The highest incidence occurs in the third and fourth decades of life, affecting most frequently the trunk and proximal extremities. Ultrasound is performed in those cases where the clinical appearance of the lesion is not typical and when the physician wants to determine the extent and depth of the lesion. MATERIAL AND METHODS: Retrospective analysis of the ultrasound and demographic findings of thirteen patients with DFSP. RESULTS: 13 patients, 8 females and 5 males, aged from 2 months to 58 years old. One patient with two different separated synchronous tumors. On ultrasonography they compromised the dermal hypodermal layers in 93% of the cases and 1 dermal lesion. The compromise reached the aponeurotic plane in two cases. The sized varied from 5 to 38 mm. They presented as a well-defined hypoechogenic nodule in seven cases (50%). In three cases (21%) they presented as a hypoechogenic infiltrate ill-defined border solid lesion; in two cases as a plaque ill-defined lesion, and two cases as a pseudonodular inflammatory lesion with irregular borders. All lesions appeared vascularized on color Doppler imaging. CONCLUSION: DFSP is a low grade sarcoma of fibroblastic origin, that usually arises in the dermis and infiltrates the subcutaneous tissue. The clinical presentations are variable. On ultrasound we found different patterns: well-defined hypoechogenic solid nodule, hypoechogenic infiltrate ill-defined border solid lesion, plaque ill-defined lesion, and pseudonodular inflammatory lesion. It is important to know and recognize this suspicious different ultrasound presentations in order to recommend a histological study.

Machine learning-based radiomics analysis for predicting local recurrence of primary dermatofibrosarcoma protuberans after surgical treatment.

BACKGROUND AND PURPOSE: Dermatofibrosarcoma protuberans (DFSP) is characterized by locally invasive growth patterns and high local recurrence rates. Accurately identifying patients with high local recurrence risk may benefit patients during follow-up and has potential value for making treatment decisions. This study aimed to investigate whether machine learning-based radiomics models could accurately predict the local recurrence of primary DFSP after surgical treatment. MATERIALS AND METHODS: This retrospective study included a total of 146 patients with DFSP who underwent MRI scans between 2010 and 2016 from two different institutions: institution 1 (n = 104) for the training set and institution 2 (n = 42) for the external test set. Three radiomics random survival forest (RSF) models were developed using MRI images. Additionally, the performance of the Ki67 index was compared with the three RSF models in the external validation set. RESULTS: The average concordance index (C-index) scores of the RSF models based on fat-saturation T2W (FS-T2W) images, fat-saturation T1W with gadolinium contrast (FS-T1W + C) images, and both FS-T2W and FS-T1W + C images from 10-fold cross-validation in the training set were 0.855 (95% CI: 0.629, 1.00), 0.873 (95% CI: 0.711, 1.00), and 0.875 (95% CI: 0.688, 1.00), respectively. In the external validation set, the C-indexes of the three trained RSF models were higher than that of the Ki67 index (0.838, 0.754, and 0.866 vs. 0.601, respectively). CONCLUSION: Random survival forest models developed using radiomics features derived from MRI images were proven helpful for accurate prediction of local recurrence of primary DFSP after surgical treatment and showed better predicting performance than the Ki67 index.

Dermatofibrosarcoma protuberans misdiagnosed as sebaceous adenoma and incompletely resected in a child: A case report.

BACKGROUND: Dermatofibrosarcoma protuberans is extremely rare in children, making a correct diagnosis by clinicians is usually difficult due to its nonspecific manifestations, the recurrence of dermatofibrosarcoma protuberans after resection has always been a perplexing problem for clinicians. Ultrasound plays an irreplaceable role in the assessment of dermatofibrosarcoma protuberans, although there is a limitation in the diagnosis of the tumor. CASE REPORT: A 10-year-old boy led by his parents sought for surgical treatment because of the growing mass. Physical examination and preoperative ultrasonography showed that the mass was clear, and the routine resection of mass was performed. Six days postoperatively, histopathological examination indicated that the mass was dermatofibrosarcoma protuberans, and the peripheral and deep resection margins were positive. The patient was informed that a second extended resection was required. The second postoperative pathology showed a negative margin, and the patient was discharged. Postoperative follow-up was assessed by ultrasound examination, and the patient had no abnormalities. CONCLUSIONS: Dermatofibrosarcoma protuberans should be included in the differential diagnosis when the wide base subcutaneous lesion has suspicious features with high vascularity on ultrasound. If an ultrasound reveals a mass with abundant blood flow, clinicians should routinely perform the extended resection. Wide surgical excision may reduce the risk of reoperation and recurrence, and long-term follow-up is necessary to evaluate postoperative outcomes.

Multimodal ultrasound for preoperative evaluation of dermatofibrosarcoma protuberans: a series of 40 cases.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare, low to intermediate-grade sarcoma, which needs imaging examination. Small series of ultrasound findings in DFSP have been published; however, the usefulness of elastography and contrast-enhanced ultrasound (CEUS) in DFSP has not been studied. We aim to study multimodal ultrasound findings and report the correlation between imagings and tiny extension in DFSP for preoperative evaluation. METHODS: Two-D ultrasound, 3-D color ultrasound, elastography, and CEUS findings were retrospectively evaluated. Forty histopathologically confirmed DFSPs were studied. RESULTS: On 2-D ultrasound, 26(65%) appeared as mostly hypoechoic lesions with occasional hyperechoic dots within the tumor matrix and lobulated lateral borders. Eight (20%) lesions were multilayered. Ninety-five percent of lesions showed increased vascularity. On 3-D ultrasound, DFSPs showed branch-shaped, striped, and wrapped color patterns. Power Doppler showed mainly artery of a moderate arterial peak systolic blood flow and low resistance index. DFSP is hard on elastography. On CEUS, DFSPs showed a long peak time, low peak and a small amount of perfusion around the tumor, 73.7% (14/19) of lesions showed a heterogeneous contrast enhancement and 89.5% (17/19) of lesions showed hyper-enhancement. CEUS showed better concordance than US with histology on the maximum diameter and depth (P < 0.05). CONCLUSIONS: Multimodal ultrasound showed significant characteristics in DFSP, which would improve diagnostic accuracy. CEUS could be an effective tool to determine tiny tumor extension.

Imaging features of dermatofibrosarcoma protuberans.

Aims: The study highlights diffusion-weighted imaging (DWI) and dynamic enhancement features of DFSP and characterizes unenhanced and enhanced computed tomography (CT) and magnetic resonance imaging (MRI) scans. Settings and Design: Image findings and clinical histories of 23 patients with DFSP were reviewed. Nine patients underwent CT before and after intravenous administration of contrast material. MRI was performed for 17 patients. CT and MRI findings were analyzed using location, size, edge, shape, infiltration sign, density and signal enhancement mode, and degree. Results: Patients showed 26 superficial and one deep lesion. Ten superficial lesions bulged onto the skin surface. Fourteen lesions were well-defined and 13 ill-defined. All lesions were nodular, with nine being multilobular. Thirteen showed infiltration to adjacent skin, fat, and fascia. Seven lesions on CT were iso- or hypo-dense to muscle without calcification. Contrast-enhanced CT showed inhomogeneous moderate and progressive enhancement in the arterial phase. Small tortuous vessels were seen in the arterial phase in one case. Sixteen tumors displayed signals that were similar to muscle by T1WI. Ten lesions were either hyper-intense to muscle or iso-intense to fat; the deep DFSP was hypo-intense by T2WI. All lesions were hyper-intense homogeneously or heterogeneously under fat-suppressed T2WI. Twelve superficial lesions showed high-intermediate signal, and one deep lesion showed low-intermediate signal with DWI. Seven cases showed low signal diffusion coefficient (ADC) images. Dynamic enhancement and signal intensity-time (SI-T) curves of four tumors showed rapid SI increases followed by steady or slightly rising SI. All lesions showed inhomogeneous, progressive enhancement in the arterial phase. Conclusions: This report is the first on dynamic curves and highlights DWI and T2WI features of DFSP. DFSP can be correctly diagnosed by combining a patient's clinical manifestations with imaging characteristics.

Diagnosis and differential diagnosis of dermatofibrosarcoma protuberans: Utility of high-resolution dynamic contrast-enhanced (DCE) MRI.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a kind of low-grade malignant spindle cell neoplasm, the diagnosis, and treatment, which have markedly attracted clinicians' attention for its repeated recurrence. High-resolution magnetic resonance imaging (HR-MRI) has shown unique capabilities in diagnosis of various cutaneous tumors. MATERIALS AND METHODS: Data of 29 patients with clinically suspected DFSPs and undergoing dynamic contrast-enhanced (DCE) HR-MRI preoperatively were prospectively collected. The HR-MRI qualitative features were evaluated and compared. The DCE-associated quantitative parameters and the time-signal intensity curve (TIC) types were provided using DCE sequences. RESULTS: A total of 7 DFSPs, nine dermatofibromas (DF, including four cases of cellular variant [CDF]), 12 keloids, and one nodular fasciitis were enrolled. DFSP showed the largest major diameter and the deepest depth. Five DFSPs (71.4%) showed ill-defined margins as well as infiltration of peripheral adipose. All DFSPs showed irregular shape. Most DFSPs presented hyperintensity on T2 WI (71.4%) and iso-intensity on T1 WI (85.7%). Six cases (85.7%) had significant enhancement, and six cases (85.7%) had homogeneous enhancement. There were significant differences of Ktrans , Kep , Ve and iAUC values among DFSPs, DFs, and keloids, and DFSP had the highest values for these parameters. Six DFSPs (85.7%) and four CDFs (100%) showed type-III TICs, while the other lesions showed type-Ⅰor type-Ⅱ TICs. CONCLUSIONS: DCE-HR-MRI could show the growth characteristics of DFSPs, which was of great value for the diagnosis and differential diagnosis of DFSPs and was helpful for the determination of treatment options, thereby to improve the prognosis of patients.

Increased 68 Ga-FAPI Uptake in Dermatofibrosarcoma Protuberans.

ABSTRACT: A 47-year-old woman presented with a 6-month history of palpable masses in the right hip. The patient was subsequently enrolled in our clinical trial of 68 Ga-FAPI PET/CT study on tumors. Intense 68 Ga-FAPI activities were noted in the right hip lesions, suggestive of malignancies. Pathological examination using tissue obtained on surgical resection rendered a diagnosis of dermatofibrosarcoma protuberans.

Comparison of 68Ga-FAPI and 18F-FDG PET/CT in Dermatofibrosarcoma Protuberans.

ABSTRACT: Dermatofibrosarcoma protuberans is a rare soft tissue sarcoma with a high recurrence rate. Herein, we present 68Ga-FAPI and 18F-FDG PET/CT findings of dermatofibrosarcoma protuberans in a 45-year-old man. Dermatofibrosarcoma protuberans only shows limited FDG uptakes on 18F-FDG PET/CT, but demonstrated intense tracer uptakes on 68Ga-FAPI PET/CT. In this case, 68Ga-FAPI was superior to 18F-FDG PET/CT in detecting dermatofibrosarcoma protuberans.

A case of dermatofibrosarcoma protuberans and reflectance confocal microscopy of a post-surgical skin graft.

Dermatofibrosarcoma protuberans (DFSP) is an overall rare malignancy yet is one of the most common cutaneous sarcomas. The diagnosis of DFSP is typically made following histopathologic examination of the lesion, classically revealing a storiform pattern of spindle cells with elongated nuclei infiltrating the dermis and subcutis. Surgical excision is the standard treatment. Local recurrence is estimated to occur in 20-50% of cases, thus frequent postsurgical monitoring is required. Noninvasive imaging modalities offer a potential alternative to multiple repeat biopsies. We report the first case where reflectance confocal microscopy accompanied clinical examination in monitoring for DFSP recurrence postsurgical excision.

Micrographic Surgery Allows Fascia Preservation in Dermatofibro-sarcoma Protuberans.

Removal of the deep fascia is recommended in therapy for dermatofibrosarcoma protuberans, but its necessity in the context of micrographic surgery is unclear. A retrospective clinicopathological analysis of 48 patients with dermatofibrosarcoma protuberans treated by micrographic surgery was performed, to determine in which tumours fascia preservation was feasible and safe. Histologically, 93% of tumours on the trunk and extremities and 14% of tumours in the head and neck region were fully located above the fascia. Localization on the head and neck was the only significant risk factor for tumour extension beyond the subcutis (p<0.001). Overall, 44% of tumours were completely excised above the fascia and 56% with deeper excisions. Two deeply infiltrating tumours (4%) on the head recurred, but in none of these lesions was the fascia spared. These results show that micrographic surgery allows fascia preservation in superficial tumours outside the head and neck region.

Role of ultrasound in the diagnosis of primary and recurrent dermatofibrosarcoma protuberans.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare, low- to intermediate-grade sarcoma, which represents a diagnostic imaging challenge. This study aimed to analyze the clinical and ultrasound features of primary and recurrent DFSP to improve the diagnosis. METHODS: Clinical, imaging, and pathological data from a total of 58 patients (23 patients with primary DFSP and 35 patients with recurrent DFSP) were retrospectively reviewed. RESULTS: There was no statistically significant difference in age, sex, tumor size, or echogenicity between the two groups. Most of the primary DFSP lesions involved the overlying dermis and hypodermis, while most of the recurrent DFSP lesions were fixated to more deeply seated structures at the original surgical incision. Red nodules on the skin were found more frequently in the primary group. There were statistically significant differences in the type of lesion and ultrasound tumor morphology (p < 0.050). The lesions in the primary group showed more tentacle-like projections or a "claw" sign, while the lesions in the recurrent group were more commonly oval, lobulated, and irregularly shaped. Hypervascularity was common in both groups. CONCLUSIONS: For primary DFSP, a slow-growing, red nodule on the skin involving the overlying dermis and hypodermis, more frequently a hypoechoic mass with tentacle-like projections or a "claw" sign, was observed. For recurrent DFSP, palpable subcutaneous nodules or subcutaneous masses at the original surgical incision and oval, lobulated, and irregularly shaped lesions were more commonly observed. This may be useful for improving diagnostic accuracy.

Magnetic resonance imaging features of dermatofibrosarcoma protuberans; what the surgeon should know: a case series.

SUMMARY: Dermatofibrosarcoma protuberans (DFSP) is a rare, slow-growing, spindle cell neoplasm with low to intermediate grade malignant potential, commonly found in young and middle-aged adults, more in males than females. DFSP mostly originates in the dermis; rarely, it may be located in the deeper tissues without dermal involvement. Typically, DFSP appears as a multinodular mass, which then spreads into the subcutaneous tissues and muscle; it rarely dedifferentiates to high-grade fibrosarcoma, and more rarely, it may metastasise. We describe magnetic resonance imaging (MRI) features in three female patients with histologically proven DFSP and review the literature.

Usefulness of ultrasound in dermatofibrosarcoma protuberans and correlation with histopathological findings: A series of 30 cases.

BACKGROUND: Small series of ultrasound findings in dermatofibrosarcoma protuberans (DFSP) have been published, but the usefulness of this technique as a preoperative planning tool for tumor resection has not been studied. MATERIALS AND METHODS: We retrospectively reviewed patients with DFSP at our hospital that underwent ultrasound examination. Depth of invasion was evaluated by ultrasound and histopathology. Accuracy of ultrasound for assessing depth of tumor invasion was estimated. RESULTS: Thirty histopathologically confirmed DFSPs were studied. Classic finger-like projections were observed in 73.3% of cases. A posterior hyperechoic area extending deep into the subcutaneous tissue correlated with the honeycomb DFSP pattern and was observed in 53.3% of patients. Concordance between ultrasound and histopathologic depth measurements was excellent. Lateral tumor extension and Doppler activity were not evaluated in our series. CONCLUSION: Ultrasound showed excellent prediction of depth of invasion. Further studies are required to define the usefulness of ultrasound for determining lateral tumor extension.