Unraveling intratumoral complexity in metastatic dermatofibrosarcoma protuberans through single-cell RNA sequencing analysis

Dermatofibrosarcoma protuberans (DFSP) stands as a rare and locally aggressive soft tissue tumor, characterized by intricated molecular alterations. The imperative to unravel the complexities of intratumor heterogeneity underscores effective clinical management. Herein, we harnessed single-cell RNA sequencing (scRNA-seq) to conduct a comprehensive analysis encompassing samples from primary sites, satellite foci, and lymph node metastases. Rigorous preprocessing of raw scRNA-seq data ensued, and employing t-distributed stochastic neighbor embedding (tSNE) analysis, we unveiled seven major cell populations and fifteen distinct subpopulations. Malignant cell subpopulations were delineated using infercnv for copy number variation calculations. Functional and metabolic variations of diverse malignant cell populations across samples were deciphered utilizing GSVA and the scMetabolism R packages. Additionally, the exploration of differentiation trajectories within diverse fibroblast subpopulations was orchestrated through pseudotime trajectory analyses employing CytoTRACE and Monocle2, and further bolstered by GO analyses to elucidate the functional disparities across distinct differentiation states. In parallel, we segmented the cellular components of the immune microenvironment and verified the presence of SPP1+ macrophage, which constituted the major constituent in lymph node metastases. Remarkably, the CellChat facilitated a comprehensive intercellular communication analysis. This study culminates in an all-encompassing single-cell transcriptome atlas, propounding novel insights into the multifaceted nature of intratumor heterogeneity and fundamental molecular mechanisms propelling metastatic DFSP.

Establishment and characterization of NCC-DFSP4-C1: a novel cell line from a patient with dermatofibrosarcoma protuberans having the fibrosarcomatous transformation

Dermatofibrosarcoma protuberans (DFSP) is a superficial low-grade sarcoma, genetically characterized by a fusion gene in collagen type I α (COL1A1) gene and platelet-derived growth factor subunit β (PDGFB). DFSP is locally aggressive and does not typically metastasize. However, DFSP with fibrosarcomatous transformation, which occurs in 7-16% of DFSP cases, demonstrates a poor prognosis than classic DFSP with a higher local recurrence rate and metastatic potential. Although imatinib, a PDGF receptor inhibitor, is a potent therapeutic agent for classic DFSP, it is less effective for DFSP with fibrosarcomatous transformation. The development of definitive chemotherapies for DFSP with fibrosarcomatous transformation is required. Patient-derived tumor cell lines are indispensable tools for preclinical research to discover novel therapeutic agents. However, only seven cell lines were derived from DFSP, out of which only two were established from DFSP with fibrosarcomatous transformation. Hence, in the present study, we established a novel DFSP cell line, NCC-DFSP4-C1, from a surgically resected DFSP tumor specimen with fibrosarcomatous transformation. NCC-DFSP4-C1 harbored an identical COL1A1-PDGFB fusion gene as its donor tumor. NCC-DFSP4-C1 cells retained the morphology of their donor tumor and demonstrated constant proliferation, spheroid formation, and invasion capability in vitro. By screening a drug library, we found that bortezomib and romidepsin demonstrated the strongest suppressive effects on the proliferation of NCC-DFSP4-C1 cells. In conclusion, we report a novel cell line of DFSP with fibrosarcomatous transformation, and demonstrate its utility in the development of novel therapeutic agents for DFSP.

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.

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.

Atrophic dermatofibrosarcoma protuberans: Two case reports and literature review

Dermatofibrosarcoma protuberans is a rare, locally aggressive, slowly growing cutaneous fibroblastic sarcoma with a high recurrence rate and low metastatic potential. Atrophic dermatofibrosarcoma protuberans is a rare variant usually presents as atrophic plaques, easily neglected and misdiagnosed as benign lesions by patients and dermatologists. Here we report two cases of atrophic dermatofibrosarcoma protuberans, one of which was accompanied by pigment, and review other cases have been reported in the literature. Understanding the most up-to-date literature and early identification of these dermatofibrosarcoma protuberans variants can help clinicians avoid delayed diagnosis and improve prognosis.

Tyrosine kinase inhibitors versus radiation therapy in unresectable dermatofibrosarcoma protuberans (DFSP): A narrative systematic review

BACKGROUND

In unresectable dermatofibrosarcoma protuberans (DFSP), no clear guideline exists regarding the use of tyrosine kinase inhibitors (TKI) versus radiotherapy. This study reviews current literature regarding TKI and radiotherapy in unresectable DFSP.

METHODS

Following PROSPERO registration (CRD42021232508), a systematic literature search was performed including all studies reporting clinical results of TKI and/or radiotherapy in the treatment of unresectable DFSP. A narrative synthesis was used to compare patient characteristics, outcomes, and adverse effects.

RESULTS

Of 1345 screened studies, 14 were included for review. Patient age ranged 18-77 years and 55% were male. Radiotherapy patients exhibited lower grade disease than TKI patients. Overall clinical benefit following TKI ranged from 70% to 96%. Radiotherapy patients exhibited control or resolution on last follow-up in 90% of cases. Radiotherapy adverse effects were mild, while TKI adverse effects were more severe and managed with dose reduction.

CONCLUSION

TKI may be employed in unresectable DFSP of all histology types whereas radiation alone may be limited to low-grade and classic-type DFSP. TKI may cause more severe adverse effects compared to radiation alone.

Dermatofibrosarcoma protuberans surgery: Experiences of four African surgical oncology units and literature review

BACKGROUND AND OBJECTIVES

Dermatofibrosarcoma is a locally malignant tumor. This gives surgery a place of choice. The advent of imatinib has improved outcomes. Our aim is to describe the indications, techniques and results of surgery.

METHODS

A retrospective, multicenter, descriptive study conducted in four West African surgical oncology units. It covers dermatofibrosarcoma surgery performed between January 1, 1988 and December 31, 2020. We took into account the surgical procedure, the mode of skin coverage, adjuvant treatments and survival. Comparisons were possible using Student's t-test and Pearson's χ² .

RESULTS

We recorded 81 cases of dermatofibrosarcoma. Surgery was effective in 90.1% of cases. Wide resection was the principle with a mean resection margin of 3.8 ± 1.9 cm. healing by primary intention, flaps and healing by secondary intention were the methods of skin coverage in 30.1%, 24.7% and 41.1% respectively. The type of skin coverage was related to the topography and size of the tumor (p < 0.0001). The healing time is associated with the type of skin cover. The recurrence rate was not related to the type of skin coverage (p = 0.8).

CONCLUSIONS

Wide and deep resection in the absence of Mohs micrographic surgery ensures healthy margins. Oncoplasty reduces the healing time without increasing the risk of recurrence.

Dermatofibrosarcoma protuberans of the hallux: A case report with review of the literature

INTRODUCTION AND IMPORTANCE

Darier-Ferrand dermatofibrosarcoma (DFS) is a rare mesenchymal tumor with an aggressive local behavior, high local recurrence frequency and low metastatic potential. It commonly presents as a raised slowly growing mass. It usually occurs on trunk and proximal extremities but rarely touches distal extremities such as hands, fingers, or foot below knees.

CASE PRESENTATION

A 15-year-old girl presents with a protuberant painful mass of the right hallux of 2 years. After surgical excision, histological examination revealed a spindle shaped cells with a strong CD34 expression and the diagnosis of Darier-Ferrand dermatofibrosarcoma of the toe was confirmed. We proceeded to a review of the literature of Dermatofibrosarcoma on the toes with the aim to reveal, its clinical presentations, histopathology, and treatment options.

CLINICAL DISCUSSION

DFS represents 0.1 % of all cancers. It is a low-grade sarcoma with a locally aggressive behavior and a low metastatic potential. Only 11 cases of DFS of the toes have been reported in the literature. It usually occurs in the trunk, and proximal extremities. Histological and immunohistochemical examination are mandatory to confirm the diagnosis with diffuse expression of CD34 by the tumoral cells. Surgery is the standard treatment for localized and resectable lesions.

CONCLUSION

Darier-Ferrand Dermatofibrosarcoma is an uncommon and recurrent dreadful tumor, that rarely occurs on toes, but should be considered in front of persistent slowly growing foot lesions.

Malignant Superficial Mesenchymal Tumors in Children

Malignant superficial mesenchymal tumors are a very diverse group of neoplasms with few clinical and radiological discriminatory factors. Hence, some of these cancers are rarely suspected based on clinical and radiological grounds, others may be easily misdiagnosed, and the histological analysis of a biopsy or resection is central in the diagnostic process. In children, the age at presentation is a major element of the differential diagnosis. Some tumors have a very distinct epidemiology, while others may be seen at any age. More recently, the advances in molecular biology have greatly improved the diagnosis of mesenchymal tumors and new entities are still being described. In the present review, we provide an overview of the diversity of malignant superficial mesenchymal tumors in children, including new and/or rare entities. We discuss the important diagnostic features, be they clinical, histological, or molecular. Special attention was given to the genetic features of these tumors, particularly when they were helpful for the diagnosis or treatment.

Imaging findings of malignant skin tumors: radiological-pathological correlation

Sometimes, radiologists encounter malignant skin tumors (MSTs) during image interpretation. As MSTs require different clinical management modalities for each histological subtype, accurate preoperative diagnosis is essential. The histological subtypes of MST can be easily assessed by visual inspection or biopsy. Therefore, the significant role of radiological imaging in MSTs is to evaluate the extent of local invasion, nodal involvement, and distant metastasis, and the histological estimation of MSTs by radiological imaging has not been reported until a few years ago. However, recent studies have revealed characteristic radiological features for differential diagnosis of MSTs, such as configuration, intratumoral homogeneity, signal intensity, cyst formation, and hemorrhage. Other important clinical data for determining the histological subtype of MST include age, gender, and site of occurrence. MSTs can be categorized as epidermal, melanocytic, adnexal, and mesenchymal tumors based on the origin and have distinctive characteristics. Hence, this review article was designed to describe the clinical and radiological features of MSTs.

The EFSUMB Guidelines and Recommendations for Musculoskeletal Ultrasound - Part I: Extraarticular Pathologies

The first part of the guidelines and recommendations for musculoskeletal ultrasound, produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), provides information about the use of musculoskeletal ultrasound for assessing extraarticular structures (muscles, tendons, entheses, ligaments, bones, bursae, fasciae, nerves, skin, subcutaneous tissues, and nails) and their pathologies. Clinical applications, practical points, limitations, and artifacts are described and discussed for every structure. After an extensive literature review, the recommendations have been developed according to the Oxford Centre for Evidence-based Medicine and GRADE criteria and the consensus level was established through a Delphi process. The document is intended to guide clinical users in their daily practice.

Dermatofibrosarcoma Protuberans in Active Duty Military Personnel: A Case Report

Dermatofibrosarcoma protuberans (DFSP) is an uncommon, soft tissue sarcoma with a high rate of local recurrence, low rate of distant metastasis, and infiltrative growth. We report two cases of DFSP in young active duty military personnel. Both cases underwent primary excision at the Armed Forces Capital Hospital with positive surgical margins and underwent re-excision at Samsung Medical Center. Dermatofibrosarcoma protuberans is a rare finding, and wide local excision with or without skin flap remains the procedure of choice. Awareness of DFSP in young patients is important for proper diagnosis and treatment and to achieve local control. Complete excision of the tumor with a clear surgical margin and thorough surveillance after surgery are recommended for service members to maintain their active duty status and to prevent ineffective combat conditions.

Resection and Reconstructive Options in the Management of Dermatofibrosarcoma Protuberans of the Head and Neck

Objective To discuss resection and various reconstructive options in patients with dermatofibrosarcoma protuberans (DFSP). Methods This study was conducted at Shifa International Hospital, Islamabad, Pakistan, from May 2018 to December 2019. All patients aged 20 years or above of either gender who were diagnosed to have DFSP over this period were included in the study. All the patients underwent wide local excision of the tumor under general anesthesia. A peroperative frozen section was conducted in all the cases to confirm complete excision. Immediate reconstruction was performed following the tumor excision. The choice of reconstruction, i.e. free, regional, or local flap was based on the size of the resultant defect. Results The mean age of the patients was 37.11 ±10.91 years. There were 12 (66.7%) males and six (33.3%) females. The mean duration of the disease was 11.22 ±2.94 months. The affected anatomical site showed that the face was involved in the majority, nine (50%) patients, followed by the scalp in four (22.2%), nape of the neck in three (16.7%), and supraclavicular region in two (11.1%) patients. In most of the cases, the free flap was observed, i.e. (n=9, 50%), followed by a regional flap in seven (38.9%), and the local flap in two (10.1%) patients. Conclusion Wide local excision of the disease, confirmed on frozen section, offers improved survival. Among DFSP of the head and neck, the face was found to be the affected anatomical site in half the cases. Also, reconstruction following tumor excision with a free flap is the most favorable option among patients with DFSP.