PRAME expression in fibrosarcomatous dermatofibrosarcoma protuberans.

PRAME (PReferentially expressed Antigen in MElanoma) was first identified as a malignant melanoma-specific antigen. Recently, a few cases of fibrosarcomatous dermatofibrosarcoma protuberans (FS-DFSP) were shown to have positivity for PRAME, while conventional dermatofibrosarcoma protuberans (C-DFSP) was negative. Because PRAME may be of diagnostic utility in FS-DFSP and is raising expectations as a new immunotherapy target, we examined the positivity of PRAME in FS-DFSP. Twenty-one cases of FS-DFSP and age/sex/location-matched cases of C-DFSP as a control group were examined by immunohistochemistry for CD34 and PRAME. The results were then evaluated by H-score, which was objectively and semi-quantitatively calculated using the open-source bioimaging analysis software QuPath. The results revealed that the PRAME H-score in FS-DFSP was significantly higher than that in C-DFSP (p = 0.0137). As for CD34, the H-score in FS-DFSP was significantly lower than that in C-DFSP (p < 0.001). Using these two immunohistochemical analyses in combination, the sensitivity and specificity for the diagnosis of FS-DFSP were 86% and 90%, respectively. Double staining of CD34 and PRAME revealed that PRAME-positive and CD34-positive areas did not overlap. This is the largest study to examine PRAME expression in FS-DFSP, and it confirmed the usefulness of PRAME in diagnosing this condition.

Sclerosing Dermatofibrosarcoma Protuberans: A Possible Diagnosis When a Small Biopsy Shows Sclerotic Fibroma-Like Features.

ABSTRACT: Dermatofibrosarcoma protuberans (DFSP) is a neoplasm of intermediate malignancy with high local recurrence rates. The sclerosing variant is characterized by the presence of sclerotic areas in more than 50% of tumors and is rarely reported. In this report, we describe a case of sclerosing DFSP with areas histopathologically resembling sclerotic fibroma, where the initial biopsy tissue presented a diagnostic challenge. A 77-year-old man presented with a 2-cm firm, erythematous nodule on the chest. A punch biopsy revealed plywood-like sclerosis and spindle cells with a vaguely storiform pattern. The tumor cells were positive for CD34. Sclerotic fibroma and DFSP were considered differential diagnoses. Subsequent excisional biopsy revealed that the tumor comprised 3 different histopathological areas: classic DFSP, sclerotic fibroma-like, and giant cell fibroblastoma-like. This report highlights the importance of reevaluating the clinical context and excision for further characterization.

High-frequency ultrasound-assisted Mohs micrographic surgery for the treatment of dermatofibrosarcoma protuberans.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a superficial sarcoma characterized by infiltrative growth with tentacle-like borders. Mohs micrographic surgery (MMS) is the preferred treatment option for DFSP. However, the imprecise boundary localization in MMS leads to an increased number of Mohs layers required and a longer surgery time. High-frequency ultrasound has excellent tissue recognition capability for DFSP, allowing for precise boundary marking. MATERIALS AND METHODS: In this study, we retrospectively analyzed 14 cases of DFSP treated with MMS using preoperative ultrasound localization and three-dimensional reconstruction at Xiangya Hospital over the past 5 years. We also reviewed previous studies on MMS for DFSP treatment. RESULTS: It was found that the average number of Mohs layers for patients after preoperative ultrasound localization was 1.57, ranging from 1 to 3, which was less than the previously reported 1.86 layers, ranging from 1 to 12. This effectively reduced the number of Mohs layers required. CONCLUSIONS: By utilizing preoperative high-frequency ultrasound to determine the boundaries and depth of DFSP, the number of Mohs layers can be effectively reduced, leading to less workload for pathological examination, shorter operation time, and reduced surgical risks for patients. Ultrasound imaging data can be used for three-dimensional reconstruction, enabling less experienced Mohs surgeons to have a visual understanding of the morphology and extent of infiltration of the lesions. This aids in developing optimal surgical plans, smoothing the learning curve, and promoting the wider adoption of MMS.

Dermatofibrosarcoma Protuberans MRI: A Preliminary Comparison of Different Sequences

OBJECTIVE: The purpose of this study was to compare the image quality of different MRI sequences regarding the presentation of Dermatofibrosarcoma Protuberans (DFSP). MATERIALS AND METHODS: We retrospectively collected MRI images of 40 patients who had been pathologically diagnosed with DFSP, including 21 primary tumors and 19 recurrent tumors. The image quality of different MRI sequences was assessed subjectively by two radiologists, taking into account the display of the lesions, artifacts, and distortions, as well as the overall impact of the image quality. RESULTS: Among the 40 cases, 22 cases involved the trunk, 14 cases involved the shoulders and limbs, 2 cases involved the head and neck, 1 case involved the breast, and 1 case involved the groin. In terms of image quality, fat suppression T2-weighted images were superior to T1-weighted images and T2-weighted images (P<0.05). The difference between fat suppression T2-weighted images and contrast-enhanced images was not significant (P>0.05). As far as lesion contrast is concerned, diffusion-weighted images, fat suppression T2-weighted images, and contrast-enhanced images did not differ significantly (P>0.05). On the DWI images, there were severe magnetic artifacts and deformations. CONCLUSIONS: Fat suppression T2-weighted images and enhanced sequences produce the highest quality images, while diffusion-weighted images provide the best lesion contrast.

Metastatic presentation of dermatofibrosarcoma protuberans as massive lower gastrointestinal bleed.

Dermatofibrosarcoma protuberans (DFSP) is an aggressive tumour with multiple local recurrences and rare metastatic potential. Fibrosarcomatous transformation occurs in a few cases of DFSP which makes them more aggressive in terms of recurrence and metastasis. Here we report the case of a woman in her late 30s who presented with massive lower gastrointestinal (GI) bleeding with a history of multiple surgeries for DFSP on her anterior abdominal wall. The bleeding source was identified to be a mass lesion in the jejunum, which was excised. The patient recovered well and the histopathology revealed fibrosarcoma of the jejunum. Follow-up investigations showed multiple lung nodules, ascites and abdominal lymph nodes suggesting progressive disease. She is currently receiving chemotherapy and progressing well 3 months postoperatively. Patients with fibrosarcomatous changes within DFSP must be followed up closely as it is associated with increased metastatic potential.

Cellular and molecular landscape of primary dermatofibrosarcoma protuberans: Insights from single-cell RNA sequencing analysis.

Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous sarcoma characterized by the COL1A1-PDGFB fusion gene. This study utilized single-cell RNA sequencing to dissect the cellular and molecular landscape of primary DFSP. Distinct DFSP cell clusters, exhibiting fibroblast-like traits, revealed variations in pathways associated with proliferation, inflammation and metabolism. Differential gene expression analysis during the differentiation from tumour stem cells to DFSP cells unveiled SMOC2, DCN and TGFBR3 as potential regulators of tumour invasion and immune infiltration through VEGF/TGF-ß signalling modulation. Cellular communication analysis highlighted interactions within DFSP cell clusters and with endothelial cells, implicating molecules such as NAMPT, ANGPT2 and PTN in pathogenesis and treatment resistance. These findings offer insights into DFSP intratumour heterogeneity, elucidate molecular mechanisms underlying tumour behaviour, and suggest potential therapeutic targets.

Dermatofibrosarcoma Protuberans in "Slow Mohs-tion": Multidisciplinary Approach of A Pediatric Dermatofibrosarcoma Protuberans of the Scalp with Slow Mohs Micrographic Surgery and A Double Rotational-Advancement Scalp Flap.

Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft-tissue sarcoma with primary incidence of 4.1 per million person-years and accounts for 0.1% of all malignancies. In patients under the age of 19, DFSP comprises 6% of cases with an annual incidence of 1 in 1,000,000. It is a slow-growing malignancy with low metastatic potential. However, DFSP is notable for its high rates of local recurrence due to local invasion with its classic "finger-like" projections into normal tissue. We discuss a case of dermatofibrosarcoma protuberans on the scalp of a 14-year-old male with delayed diagnosis, which required extensive resection through slow Mohs Micrographic Surgery (sMMS). This resection created a sizeable scalp defect of nearly 100 cm 2 , which mandated creative reconstruction using a novel double rotational-advancement scalp flap to close the defect while maintaining the patient's hairline for optimal cosmesis.

ALK-rearranged, CD34-positive spindle cell neoplasms resembling dermatofibrosarcoma protuberans: a study of seven cases.

AIMS: The majority of dermatofibrosarcoma protuberans (DFSP) harbour PDGFB or PDGFD rearrangements. We encountered ALK expression/rearrangement in a PDGFB/D-negative CD34-positive spindle cell neoplasm with features similar to DFSP, prompting evaluation of ALK-rearrangements in DFSP and plaque-like CD34-positive dermal fibroma (P-LDF). METHODS AND RESULTS: We searched the archives of academic institutions for cases previously coded as DFSP and P-LDF. NGS-naïve or PDGFB-negative DFSP were screened for ALK (clone D5F3) expression by immunohistochemistry. NGS or ALK FISH was performed on ALK-positive cases. Methylome profiling studies were performed and compared with conventional DFSP. One case of "DFSP" and two "P-LDF" with ALK expression were identified from the archives, while four cases were detected prospectively. These seven cases (6F:1M; 8 months to 76 years) arose in the dermis of the arm (two), scalp, eyelid, thigh, abdomen, and shoulder and ranged from 0.4 to 4.2 cm. Tumours were composed of spindled cells and displayed a storiform growth pattern. Cytologic atypia was absent, and mitotic figures were scarce (0-2/10 HPFs, high power fields). The lesional cells were diffusely positive for CD34 and ALK and negative for S100 protein. By NGS (n = 5), ALK fusion partners included DCTN1 (2), PLEKHH2, and CLIP2 in DFSP-like cases and FLNA in P-LDF-like lesions. ALK FISH was positive in one (of two) cases previously labelled P-LDF. Methylome profiling of two (of three) ALK-rearranged DFSP-like tumours showed clustering with conventional DFSP in the UMAP dimension reduction plot. To date, no tumour has recurred (n = 2; 26, 27 months). CONCLUSION: We describe a cohort of novel ALK-rearranged tumours with morphologic features similar to DFSP.

Analysis of surgical margins and prognostic factors in dermatofibrosarcoma protuberans after wide local excision: A multicenter study of 116 Japanese patients.

Cutaneous dermatofibrosarcoma protuberans (DFSP) is a fibrohistiocytic tumor characterized by a high risk of local recurrence but a low risk of metastasis. Wide local excision (WLE) has been an important treatment option, but its clinical outcomes and safety have not been thoroughly evaluated in previous reports. The aim of this study was to determine appropriate surgical margins (deep and lateral) and prognostic factors associated with recurrence-free survival (RFS) of DFSP. A database collected by two dermatology departments in Japan was retrospectively reviewed to identify 116 patients with DFSP who underwent complete resection with WLE between 1994 and 2021. Sixty-one men (53%) and 55 women (47%) were included in our cohort. The primary sites of DFSP were as follows: 11 head and neck (9%); seven face (7%); 12 upper extremities (10%); 20 lower extremities (17%); and 66 trunk (57%). There were 103 cases (89%) of primary DFSP and 13 cases (11%) of recurrent DFSP. Total 10-year RFS was 96.6%. There were significant differences in RFS by tumor size (median size: 3 cm), disease status (primary versus recurrent DFSP), and fibrosarcomatous change (positive versus negative) (all p < 0.05). Two patients (1.7%) with buccal or head lesions had positive deep margins. In all cases, the lateral margin was negative at the postoperative evaluation. Tumor size, disease status, and fibrosarcomatous change are important risk factors for recurrence. Both face and head-neck lesions were more likely to have positive deep margins than other anatomic areas in DFSP. Although this study was limited by its retrospective design, a narrow 2-cm lateral margin is especially considered for low-risk patients.

A cutaneous spindle cell neoplasm characterized by a COL3A1::PDGFRA fusion.

Cutaneous spindle cell neoplasms can be challenging to diagnose using routine histopathological techniques alone, and the growing repertoire of molecular studies can assist in diagnosis. We describe a cutaneous spindle cell neoplasm characterized by a COL3A1::PDGFRA rearrangement predicted to lead to constitutive activation of the PDGFRA kinase domain. The lesion shows some similarities to dermatofibrosarcoma protuberans and also benign and epithelioid fibrous histiocytomas but is distinct from these entities histopathologically and molecularly. This tumor is considered to represent an entity in the spectrum of PDGFR-driven cutaneous mesenchymal neoplasms.

Fibrosarcomatous Transformation in Dermatofibrosarcoma Protuberans of the Male Breast and its Association with Magnetic Resonance Imaging and Immunohistopathologic Features.

BACKGROUND: Dermatofibrosarcoma Protuberans (DFSP) is a rare soft tissue sarcoma, accounting for approximately 1% of all tumors; however, DFSP of the breast is extremely rare. Moreover, DFSP generally has a low malignant potential and is characterized by a high rate of local recurrence along with a small but definite risk of metastasis. The risk of metastasis is higher in fibrosarcomatous transformation in DFSP than in ordinary DFSP. CASE REPORT: We have, herein, reported a case of a 61-year-old male patient with fibrosarcomatous transformation in DFSP. Preoperative Dynamic Contrastenhanced Magnetic Resonance Imaging (DCE-MRI) of the breast revealed an oval-shaped mass with heterogeneous internal enhancement, a large vessel embedded within, and a washout curve pattern on kinetic curve analysis. The mass exhibited a hyperintense signal on Diffusion-weighted Imaging (DWI), with a low apparent diffusion coefficient value. Histologically, the bland spindle tumor cells were arranged in a storiform pattern. Areas with the highest histological grade demonstrated increased cellularity, cytological atypia, and mitotic activity. Immunohistochemically, Ki-67 and p53 were highly expressed. CONCLUSION: Recognizing the risk and accurately diagnosing fibrosarcomatous transformation in male breast DFSP are critical for improving prognosis and establishing appropriate treatment and follow-up plans. This emphasizes the significance of combining immunohistopathological features with DCE-MRI and DWI to assist clinicians in the early and accurate diagnosis of sarcomas arising from male breast DFSP.

An unusual presentation of dermatofibrosarcoma protuberans: A case of fibrosarcomatous dermatofibrosarcoma protuberans with pleomorphic angiectatic tumor-like changes.

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive superficial mesenchymal neoplasm characterized by monomorphic spindle-cell proliferation with a storiform pattern. It can demonstrate pigmentation, myxoid changes, myoid differentiation, plaque-like growth, and fibrosarcomatous features; its varied presentation often complicates diagnosis. We report an extremely rare case of fibrosarcomatous DFSP with features reminiscent of a pleomorphic hyalinizing angiectatic tumor (PHAT) in a 73-year-old male. The diagnosis was confirmed using a reverse transcription polymerase chain reaction. To the best of our knowledge, PHAT-like changes in DFPS have not been described so far. Therefore, this report provides a novel variant of DFSP and expands the differential diagnosis of DFSP and PHAT.

Dermatofibrosarcoma protuberans of the breast.

Dermatofibrosarcoma protuberans (DFSP) of the breast is an infrequent soft tissue sarcoma that usually affects young to middle-aged women. Our case report describes a unique occurrence of DFSP of the breast in an adolescent girl, which was initially being managed as a keloid for 2 years under dermatology despite being refractory to treatment. Once the diagnosis of DFSP was confirmed through punch biopsy, our patient underwent surgical excision of the lesion under general anaesthesia. Our patient was at an increased risk of damage to the ductal system due to proximity of the lesion to the nipple-areolar complex, warranting the need for early recognition and treatment. As demonstrated by our case, DFSP of the breast can be difficult to diagnose since it resembles a range of benign and malignant pathologies of the breast.

In vitro modeling of recurrent Dermatofibrosarcoma Protuberans: Assessment of 5-aminolevulinic acid photodynamic therapy efficacy.

BACKGROUND: Dermatofibrosarcoma Protuberans (DFSP) is a rare, low-grade malignant tumor of the dermis with a high recurrence rate post-surgery. Current treatments, including surgery, radiotherapy, and targeted therapy, have limitations. Photodynamic therapy (PDT) with 5-aminolevulinic acid (5-ALA) is a promising non-invasive approach, but its efficacy in DFSP treatment remains underexplored. METHODS: This study aimed to evaluate the anti-tumor efficacy of 5-ALA PDT using an in vitro model derived from a recurrent DFSP patient. The cells were treated with varying concentrations of 5-ALA and exposed to red light, followed by assessments of cell viability, proliferation, apoptosis, migration, invasion, angiogenesis, and expression of DFSP-related genes and proteins. RESULTS: 5-ALA PDT significantly reduced DFSP cell viability in a dose-dependent manner and induced apoptosis. It also effectively inhibited cell proliferation, migration, and invasion, as well as suppressed angiogenic activity in conditioned media. Furthermore, 5-ALA PDT downregulated the expression of COL1A1 and PDGFRB, key genes in DFSP pathogenesis. CONCLUSIONS: The findings provide the first evidence of 5-ALA PDT's in vitro anti-tumor efficacy against DFSP, suggesting its potential as a novel therapeutic approach for DFSP. Further studies are warranted to explore the clinical utility of 5-ALA PDT in preventing DFSP recurrence.

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.