Expression of the human progenitor cell antigen CD34 (HPCA-1) distinguishes dermatofibrosarcoma protuberans from fibrous histiocytoma in formalin-fixed, paraffin-embedded tissue

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.

Dermatofibrosarcoma protuberans: a case report of an abdominal wall mass and review of the literature

Dermatofibrosarcoma protuberans (DFSP) is a rare, slow-growing malignancy that often presents with an ambiguous clinical presentation due to its nonspecific findings. We present the case of a 41-year-old male who presented with a slow-growing mass on his abdomen that became protuberant and firm, prompting his desire to pursue excision. Upon return of histologic examination, the specimen was noted to be DFSP. DFSP is a rare cutaneous neoplasm that originates from the dermis and invades the underlying tissue creating a classic protuberant appearance. In some cases, chemotherapy and radiation may be indicated based on margins and locations. The sarcoma is notoriously complicated with early recurrence, making the disease process difficult to control. Surgeons should be familiar with this malignancy due to the indication of additional nonsurgical treatments and the necessity for long-term follow-up for surveillance of recurrence.

Dermatofibrosarcoma protuberans in a pre-adolescent child

INTRODUCTION

Dermatofibrosarcoma protuberans (DFSP) is a rare skin sarcoma with a slow growth rate and less chance of metastasizing but it is associated with higher morbidity due to its aggressive nature of local infiltration and its recurrence nature.

IMPORTANCE

When dealing with DFSP in children we could achieve low morbidity with appropriate surgical planning and approach even though aggressive wide local excision was performed.

CASE REPORT

12-year boy presented with a lump in his left arm which was initially clinically and ultrasonically diagnosed as lipoma. However, histological examination, coupled with CD34 immunohistochemistry, confirmed the diagnosis as DFSP.

CLINICAL DISCUSSION

Modern microsurgical methods, such as Mohs micrographic surgery, are advocated as effective treatment options, their availability and feasibility may be limited in certain settings. Therefore, the classic approach of wide local excision remains the treatment of choice in the majority of cases, with radiotherapy recommended for recurrent disease. Proper patient education and regular surveillance will help identify recurrence in time which aids us to provide timely intervention and optimize outcomes for patients with dermatofibrosarcoma protuberans.

CONCLUSION

Accurate diagnosis using histology coupled with immunohistochemistry, proper surgical technique and regular follow up are the three pillars of managing DFSP.

CD34 and CD105 Microvessels in Resected Bone Specimen May Implicate Wound Healing in MRONJ

Clinical treatment outcome of MRONJ (medication-related osteonecrosis of the jaw) surgery despite radical osseous removal and primary closure healing still shows differences in terms of outcome and disease recurrence. The study aims to assess the rate of angiogenesis of MRONJ lesions in order to understand the impact of angiogenesis and neoangiogenesis status on MRONJ surgical treatment outcome. This is the first study correlating microvessel density with prognosis in MRONJ surgically-treated patients. The immunohistochemical expression of CD34 and CD105 in MRONJ specimens obtained from surgically-treated patients was evaluated. The most vascularized areas detected by CD34 and CD105 were selected and the microvessel density value of the samples was registered. Samples were retrospectively divided according to the clinical outcome of MRONJ surgical treatment, dividing patients into two groups, “healed” and “not healed”. Statistical analysis was performed to assess if neovessels could influence treatment outcome in patients undergoing radical surgery. In the examined cohort, this value was highly predictive of better treatment outcome after radical surgery of MRONJ. Understanding of angiogenesis-dependent factors deserves further attention as a future target for MRONJ prevention and therapies.

Advanced dermatofibrosarcoma protuberans: an updated analysis of cases from an Indian sarcoma clinic

AIM

Dermatofibrosarcoma protuberans (DFSP) accounts for less than 2% of all soft-tissue sarcomas.

PATIENTS & METHODS

We retrospectively reviewed our database for patients with locally advanced or metastatic DFSP who had presented to our clinic between January 2016 and January 2020.

RESULTS

We identified a total of 14 patients, of whom ten had sarcomatous transformation. Eleven cases had metastatic disease and three were locally advanced. The initial partial response rate to first-line imatinib was 76.9% and the overall median progression-free survival on imatinib was 15 months.

CONCLUSION

We had a high proportion of patients with sarcomatous transformation, in contrast to their relative rarity in the West. While most patients had initial good responses to imatinib, second-line therapies were not as effective.

Practical Application of Cytology and Core Biopsy in the Diagnosis of Mesenchymal Tumors

Soft tissue neoplasms are increasingly being sampled by core needle biopsy and fine-needle aspiration (FNA), and these small biopsy specimens pose unique diagnostic challenges. Many advances in ancillary testing enable detection of characteristic immunophenotypes and molecular alterations, allowing accurate classification of soft tissue tumors in these small biopsy samples. This review outlines pattern-based diagnostic approaches to core biopsies and FNAs of soft tissue neoplasms, including formulation of practical differential diagnoses and relevant application of ancillary tests.

Dermatofibrosarcoma protruberans of the scalp treated with customised surface mould high-dose-rate (HDR) brachytherapy: a case report

Dermatofibrosarcoma protuberans (DFSP) is a rare, locally aggressive soft tissue tumor commonly occurring in the trunk or extremities, lesser than 5% being located on the scalp. Surgery is the mainstay of management of this locally infiltrative cutaneous soft tissue sarcoma, with a high probability of recurrence if margin remains positive or inadequate. Adjuvant radiotherapy to a dose of 40–60 Gy decreases this chance of recurrence considerably. Radiotherapy is generally delivered by interstitial HDR brachytherapy, opposed photon or electron beam. We report a case of a 24 year old female, presenting with a small, painless nodule over right frontal area of scalp, diagnosed as DFSP post surgery with close margin that was treated with adjuvant radiation customized HDR surface mould brachytherapy with good local control and cosmesis.

Dermatofibrosarcoma Protuberans: Insights into a Rare Soft Tissue Tumor

Dermatofibrosarcoma protuberans (DFSP) is a rare soft tumor which originally represents a cutaneous sarcoma. It grows slowly and presents usually as nodular superficial lesion on the trunk or the extremities. Although these tumors are locally aggressive with high rate of recurrence following surgery; the prognosis is considered excellent when it is effectively treated. The radiological appearance of this tumor has rarely been studied and findings infrequently discussed in the literature probably because many lesions underwent resection before imaging. Although imaging is infrequently performed for this lesion; it can show characteristic features and demonstrate the full extent. Imaging may also play a role in the differentiation of this tumor from more serious soft tissue lesions such as more aggressive sarcomas and hemangioma. In this article, we discuss the imaging findings of DFSP that can aid in its diagnosis and its variable appearances. In addition; the clinical presentation and treatment options are also described with review of the previous literature.

Toward angiogenesis of implanted bio-artificial liver using scaffolds with type I collagen and adipose tissue-derived stem cells

Backgrounds/Aims

Stem cell therapies for liver disease are being studied by many researchers worldwide, but scientific evidence to demonstrate the endocrinologic effects of implanted cells is insufficient, and it is unknown whether implanted cells can function as liver cells. Achieving angiogenesis, arguably the most important characteristic of the liver, is known to be quite difficult, and no practical attempts have been made to achieve this outcome. We carried out this study to observe the possibility of angiogenesis of implanted bio-artificial liver using scaffolds.

Methods

This study used adipose tissue-derived stem cells that were collected from adult patients with liver diseases with conditions similar to the liver parenchyma. Specifically, microfilaments were used to create an artificial membrane and maintain the structure of an artificial organ. After scratching the stomach surface of severe combined immunocompromised (SCID) mice (n=4), artificial scaffolds with adipose tissue-derived stem cells and type I collagen were implanted. Expression levels of angiogenesis markers including vascular endothelial growth factor (VEGF), CD34, and CD105 were immunohistochemically assessed after 30 days.

Results

Grossly, the artificial scaffolds showed adhesion to the stomach and surrounding organs; however, there was no evidence of angiogenesis within the scaffolds; and VEGF, CD34, and CD105 expressions were not detected after 30 days.

Conclusions

Although implantation of cells into artificial scaffolds did not facilitate angiogenesis, the artificial scaffolds made with type I collagen helped maintain implanted cells, and surrounding tissue reactions were rare. Our findings indicate that type I collagen artificial scaffolds can be considered as a possible implantable biomaterial.

Calibre Persistent Labial Artery: Clinical Features and Immunohistochemistry Diagnosis

Calibre persistent labial artery (CPLA) usually presents as an asymptomatic papule on the lower lip and can be easily misdiagnosed as a mucocele, haemangioma, venous lake, varix or fibroma. When it is ulcerated, squamous cell carcinoma is the most usual differential diagnosis. Here, we report a case of a 25-year-old woman with no previous relevant medical history who presented with a complaint of an asymptomatic, non-ulcerated, progressively growing nodule (over the last 5 months) on the upper lip. In this case, the diagnosis was made clinically and confirmed by immunohistochemical analysis. We conclude that clinicians should be aware of CPLA and it should be included in the differential diagnosis of labial mucosal papules. Sometimes, the immunohistochemical analysis is necessary to make a correct diagnosis.

Immunohistochemical markers in fibrohistiocytic lesions: factor XIIIa, CD34, S-100 and p75

BACKGROUND

The distinction between dermatofibroma (DF), dermatofibrosarcoma protuberans (DFSP), and other benign and malignant cutaneous spindle cell lesions frequently requires immunohistochemical staining. CD34 and factor XIIIa are the most commonly used immunostains; however, they may exhibit aberrant expression and introduce the potential for misdiagnosis. There is some data supporting that p75 and S100A6 may be additional helpful immunohistochemical markers.

METHODS

We undertook a large case series examining the use of CD34 and factor XIIIa as well as p75 and S100A6 in DF, cellular DF, DFSP, indeterminate fibrohistiocytic lesion, and scar.

RESULTS

As expected, CD34 stained DFSP, although it was usually negative in DF. Factor XIIIa was generally positive in DF and negative in DFSP. There were exceptions in both cases of DF and DFSP. S100A6 was routinely negative in all entities studied. P75 was negative in all cases except DFSP, approximately half of which showed weak and/or patchy positivity.

CONCLUSIONS

We conclude that to date, CD34 and factor XIIIa remain the most reliable immunohistochemical markers for DF and DFSP.

Report of two cases of recurrent scalp dermatofibrosarcoma protuberans and literature review

Dermatofibrosarcoma protuberans (DFSP) are rare malignant skin tumor, and scalp DFSP is even lesser than 5% of all DFSP, therefore, being seldom reported. We recently treated two cases of recurrent scalp DFSPs. One was a 38-year-old male, who accept lumpectomy for the first time; however, it recurred 9 months later. We then performed a wide excision resulting in no recurrence in the subsequent 4 years. Another patient was a 26-year-old female, who accept an in situ tumorectomy for the first time, and 2 years later; the recurrent mass became 9 × 9 cm in size. We gave her another operation, but only 3 months later local recurrence appeared. For the both cases, we collected their case histories, intraoperative findings, pathologic detections, and follow-up results, all of which may help the dermatologists to extend knowledge about this rare disease. Moreover, an exhaustive review of the literature is included with emphasis on diagnosis, different diagnosis and treatments.

Bednar Tumor: A Report of Two Cases

We have recently treated two Japanese with Bednar tumor, pigmented dermatofibrosarcoma protuberans. The tumors were multilobular with brown-pigmentation and an irregular surface. Firm nodules were growing into the deep subcutaneous tissue, but they were movable over the underlying tissue. Histopathological examination and immunohistochemical studies showed the typical features of Bednar tumor and positive staining for CD34, which is known to be expressed in dermatofibrosarcoma protuberans. Bednar tumor is thought to be a variant of dermatofibrosarcoma protuberans and to have intermediate malignancy.

Molecularly targeted therapies for nonmelanoma skin cancers

Over the past two decades, advances in the fields of cancer genetics and molecular biology have elucidated molecular pathways that cause numerous cutaneous malignancies. This in turn has spurred the rational design of molecularly targeted therapies. In this review, we discuss the molecular pathways critical to the development of nonmelanoma skin cancers and the novel pharmacologic agents that target them. Included is a review of vismodegib for basal cell carcinoma, cetuximab for squamous cell carcinomas, imatinib for dermatofibrosarcoma protuberans, and sirolimus for Kaposi's sarcoma.

Immunohistochemistry of soft tissue tumours - review with emphasis on 10 markers

Immunohistochemistry is an integral component in the proper analysis of soft tissue tumours, and a simple panel of six markers is useful in practical triage: CD34, desmin, epithelial membrane antigen (EMA), keratin cocktail AE1/AE3, S100 protein and alpha smooth muscle actin (SMA). These markers frequently assist in the differential diagnosis of fibroblastic, myoid, nerve sheath and perineurial cell tumours, synovial and epithelioid sarcoma and others. However, they all are multispecific, so that one has to be cognizant of their distribution in normal and neoplastic tissues. Four additional useful markers for specific tumour types are discussed here: CD31 and ERG for vascular endothelial tumours, and KIT and DOG1/Ano-1 for gastrointestinal stromal tumours (GISTs). However, hardly any marker is totally monospecific for any one type of tumour. Furthermore, variably lineage-specific markers do not usually distinguish between benign and malignant proliferations, so that this distinction has to be made on histological grounds. Immunohistochemical evaluation is most useful, efficient and cost-effective when used in the context of careful histological evaluation by an experienced pathologist, aware of all diagnostic entities and their histological spectra. Additional diagnostic steps that must be considered in difficult cases include clinicoradiological correlation and additional sampling of remaining wet tissue, if possible.

Fibrosarcoma: a review and update

Adult fibrosarcoma, defined by the World Health Organization as a 'malignant neoplasm composed of fibroblasts with variable collagen production and, in classical cases, a "herringbone" architecture', is a very rare soft tissue sarcoma. Once considered the most common adult sarcoma, the incidence of adult fibrosarcoma has declined dramatically over the past several decades. This is due to (i) evolution in the classification of soft tissue tumours (ii) recognition of clinically, morphologically and genetically distinctive subtypes of fibrosarcoma and (iii) increased understanding of the many other mesenchymal and non-mesenchymal tumours that may mimic fibrosarcoma. This review article will summarize the current state of our knowledge about strictly defined adult fibrosarcoma and discuss important entities in its differential diagnosis, including various fibrosarcoma variants, monophasic synovial sarcoma and other potential mesenchymal and non-mesenchymal mimics.

Dermatofibrosarcoma protuberans in an adolescent: a case report and review of the literature

Classically, dermatofibrosarcoma protuberans (DFSP) is a disease of adults. The world literature revision shows that several pediatric cases have been reported so far; this might suggest that the number of infants with the condition might be larger than that estimated previously. Here, we report the 183rd case of histologically confirmed DFSP in young age. A 14-year-old white male patient came under our care for a slowly growing, pale brownish lesion on the neck skin. A biopsy specimen showed a DFSP. Subsequently, a wide surgery excision with 3 cm of resection margins including the underlying fascia was performed. To date, the patient has been in follow-up for 6 years without evidence of recurrent disease. The clinical features and treatment of DFSP diagnosed in childhood and adolescence reported in the published literature are reviewed to provide new insights about this rare entity. The aim is to emphasize the importance of biopsy for histologic evaluation in the cases that show a persistent or a large cutaneous plaque or nodule without pathognomonic clinical features that permit a clinical diagnosis. An accurate knowledge of the disease is the prerequisite for a wider recognition and appropriate treatment.

Dermatofibrosarcoma protuberans: Our experience of 59 cases

Dermatofibrosarcoma protuberans (DFSP) is a rare soft tissue tumor with intermediate malignancy. It is initially located on the skin from where it is able to infiltrate the deep structures and has a tendency to recur locally following inadequate excision. A t(17;22)(q22;q13) chromosome trans-location is the main cytogenetic alteration responsible for the onset of DFSP. Treatment options include complete surgical excision by performing conventional surgery with wide margins (>3 cm) or Mohs micrographic surgery. A retrospective study was conducted in our Department of Plastic and Reconstructive Surgery and all data were collected from medical records of 59 DFSP patients within this department from 1999 to 2011. A total of 13 of 59 (22%) cases were treated with conventional excision; 3 (5%) cases resulted in tumor-free margins, 8 (14%) cases required surgical revision and 2 (3%) cases lead to recurrence. A total of 46 of 59 (78%) cases were treated with wide excision; 43 (73%) cases resulted in tumor-free margins, 3 (5%) cases required surgical revision and 0 (0%) cases lead to recurrence. In conclusion, the data collected reveal the controversy surrounding the adoption of general guidelines regarding safe margins. Further studies are required to investigate the possibility of obtaining genotypically altered margins from margins that may appear phenotypically healthy.

A study on the prognostic value of clinical and surgical features of dermatofibrosarcoma protuberans in Korean patients

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare spindle cell tumour with locally aggressive characteristics. Only few studies on the epidemiology of DFSP in Asians have been reported.

OBJECTIVES

: The purpose of the study was to evaluate the epidemiological and clinical characteristics of DFSP in Korean patients and determine the prognostic factors that affect disease-free survival.

METHODS

We conducted a retrospective review of patients diagnosed with primary or recurrent DFSP between 2000 and 2009 at three Seoul National University Hospitals. Patient, tumour and treatment factors were analysed for local recurrence-free survival.

RESULTS

We analysed data for 65 patients, of whom 36 (55.4%) were female. The mean age at disease onset was 34.4 years with 50% aged between 20 and 40 years. Involved sites were most often on the trunk (66.1%). Among the 65 patients, 60 patients underwent wide excision; seven patients (10.8%) experienced local recurrence during 3.6 years of follow-up. The recurrence-free survival was significantly related to the microscopic resection margins (P = 0.005), clinical presentation (P = 0.002) and frequency of recurrence (P = 0.014) in the univariate analysis. There were three cases with metastasis, two of whom died because of progression of the disease despite continuous chemotherapy with imatinib mesylate.

CONCLUSIONS

We report the epidemiologic and clinical characteristics of DFSP in Korea. Patients with recurrent disease at presentation and frequent recurrence have a high risk of recurrence and metastasis, and therefore close observation is needed in these patients.

Identification of mesenchymal stem cells in perinodular fat and skin in Dupuytren's disease: a potential source of myofibroblasts with implications for pathogenesis and therapy

Dupuytren's disease (DD) is a fibroproliferative disorder characterized by aberrant proliferation of myofibroblasts, the source of which remains unknown. Recent studies indicate that circulating and tissue-resident mesenchymal stem cells (MSCs) can differentiate into myofibroblasts. Therefore, the aim of this study was to profile MSCs from phenotypically distinct DD sites including cord, nodule, skin overlying nodule (SON), and perinodular fat (PNF) compared with unaffected internal controls, that is, distant palmar fat (DPF) and transverse palmar fascia (Skoog's fibers) as well as external control carpal tunnel (CT) tissue including skin, fat, and fascia. Freshly isolated primary fibroblasts as well as cells grown up to passage 5 (P5) from DD (n=27) and CT (n=14) samples were analyzed for the presence of established MSC markers CD73, CD90, and CD105 and absence of hematopoietic marker CD34 using fluorescence-activated cell sorting, in-cell quantitative western blotting, immunohistochemistry, and immunocytochemistry. Freshly isolated cells from SON, PNF, and cord biopsies had a higher number of CD34(-)73(+)90(+)105(+) cells compared with Skoog's fibers and CT controls. P3 cells obtained from all DD biopsies compared with CT samples differentiated into osteocytes, adipocytes, and chondrocytes. P3 cord and nodule cells expressed intense α-smooth muscle actin staining compared with skin and fat cells. Stem cell markers including stem cell factor, MSC-homing marker CXCR4, and Wnt/β-catenin downregulator Dkk-1 were all upregulated in SON and PNF compared with CT skin and CT fat, respectively, as shown by real-time quantitative polymerase chain reaction. However, osteogenic marker OSF-1 had a significantly higher expression in the PNF (P=0.002) and cord (P=0.01) compared with the nodule. In conclusion, we have shown the presence of MSCs in specific DD tissue phenotypes compared with internal and external control tissue. These findings provide preliminary support for a potential alternative source of disease myofibroblasts originating from sites such as SON and PNF as opposed to palmar fascia alone.

Dermatofibrosarcoma protuberans: a clinicopathological, immunohistochemical, genetic (COL1A1-PDGFB), and therapeutic study of low-grade versus high-grade (fibrosarcomatous) tumors

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is an uncommon cutaneous tumor, usually low grade, except for the fibrosarcomatous variant (DFSP-FS).

OBJECTIVES

We sought to compare the clinicopathological, immunohistochemical, genetic, and therapeutic features between DFSP and DFSP-FS.

METHODS

The clinicopathological features were reviewed in 63 DFSP and 12 DFSP-FS. Immunohistochemistry and multiplex reverse transcriptase-polymerase chain reaction were carried out using formalin-fixed, paraffin-embedded tissue, using specific primers for collagen type I alpha 1 (COL1A1) and platelet-derived growth factor beta (PDGFB).

RESULTS

DFSP-FS was associated with tumor history longer than 5 years (P = .009), tumor size greater than 4 cm (P = .001), more stages of modified Mohs micrographic surgery (P = .005), expansive subcutaneous infiltration (P = .005), muscular invasion (P = .0001), absence of CD34 staining (P = .018), p53 positivity (P = .006), and increased proliferative activity (P = .004) compared with DFSP. The COL1A1-PDGFB fusion transcript was found in 100% DFSP-FS and 72% DFSP. No association was found between the different COL1A1-PDGFB fusion transcripts and the different histologic subtypes. Wide local excision (2 cm) was performed in 47% of cases and modified Mohs micrographic surgery in 53%. After a mean follow-up of 73 months (range 21-235), 6 patients had local recurrence (5 DFSP, 1 DFSP-FS) and one died of disease (DFSP-FS). The only factor related to local recurrence was the type of surgery (17% wide local excision vs 0% modified Mohs micrographic surgery) (P = .006).

LIMITATIONS

Our study is retrospective. Prospective studies are necessary to confirm our results.

CONCLUSIONS

DFSP-FS reflects tumor progression in DFSP, with larger size, particular invasive patterns, p53 expression, and increased proliferative activity. However, as in low-grade DFSP, appropriate surgery permits a tumor-free excision. COL1A1-PDGFB is a useful tool for diagnosis of DFSP and particularly for DFSP-FS.

D2-40, a novel immunohistochemical marker in differentiating dermatofibroma from dermatofibrosarcoma protuberans

The distinction between dermatofibroma, particularly cellular variant, and dermatofibrosarcoma protuberans in excisional biopsies is usually straightforward. However, a separation between the two may be sometimes challenging, especially in superficial biopsies. Although factor XIIIa and CD34 immunostains are useful in differentiating dermatofibroma and dermatofibrosarcoma protuberans in most instances, focal CD34 positivity may be seen in cellular fibrous histiocytoma. Some cases reveal overlapping immunostain results. D2-40 identifies a 40-kDa O-linked sialoglycoprotein present on a variety of tissues including testicular germ cell tumors as well as lymphatic endothelium. In this study, we investigated the utility of D2-40 in separating dermatofibroma from dermatofibrosarcoma protuberans and compared the results with other commonly used immunostains. Fifty-six cases of dermatofibroma (including six cellular variant) and 29 cases of dermatofibrosarcoma protuberans were retrieved from the archives of Department of Anatomic Pathology at Sunnybrook Health Sciences Center in University of Toronto. We applied factor XIIIa, CD34, and monoclonal mouse anti-D2-40 immunostains to formalin-fixed, paraffin-embedded tissue sections. All 56 (100%) cases of dermatofibroma demonstrated strong and diffuse immunoreactivity to D2-40 in the spindle cells and stroma. Similarly, factor XIIIa showed strong and diffuse positivity in the spindle cells. Nearly all dermatofibromas were negative for CD34 except one case revealing focal positivity. None of dermatofibrosarcoma protuberans cases were labeled by D2-40, although four cases showed weak and patchy background staining in contrary to diffuse, strong, and crisp staining seen in dermatofibromas. Our results indicate that D2-40 seems to be a sensitive immunohistochemical marker for dermatofibromas, including cellular variant. Focal and faint D2-40 staining may be seen in the stroma of dermatofibrosarcoma protuberans. Our findings suggest that D2-40 can be used as a complementary immunostain to factor XIIIa and CD34 in problematic and challenging cases on superficial biopsies.

Dermatofibrosarcoma protuberans: clinical, pathological, and genetic (COL1A1-PDGFB ) study with therapeutic implications

AIMS

To analyse the presence of collagen type I alpha 1-platelet-derived growth factor beta (COL1A1-PDGFB) transcripts in 20 cases of dermatofibrosarcoma protuberans (DFSP) and to assess the relationship between COL1A1 breakpoints and clinical and histopathological variables.

METHODS AND RESULTS

Multiplex reverse transcriptase-polymerase chain reaction was carried out using frozen tissue. Our series contained 14 men and six women. Histologically, most cases were of conventional type (n = 9), followed by fibrosarcoma (n = 4), Bednar tumour (n = 2), sclerosing (n = 2), myoid (n = 1) and atrophic (n = 1) DFSP, and giant cell fibroblastoma (n = 1). Immunohistochemistry revealed CD34 expression in 90% of cases. COL1A1-PDGFB fusion transcripts were present in 89% of cases (exons 18, 19, 20, 25, 26, 31, 33/34, 39, 40, 46, 47 and 48 of COL1A1 with exon 2 of PDGFB). There was no recurrence of DFSP in any of the 19 patients treated by Mohs surgery. A partial response was obtained in the two patients treated with imatinib.

CONCLUSIONS

The COL1A1-PDGFB fusion was present in all histological subtypes of DFSP, but not all cases expressed the fusion transcript. No association was observed between different COL1A1 breakpoints and clinicopathological parameters. Imatinib mesylate can be useful in locally advanced tumours and metastases.

Dermatofibroma and Dermatofibrosarcoma Protuberans: A Comparative Ultrastructural Study

Dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP) are dermal tumors whose histogenesis has not been well defined to date. The differential diagnosis in most cases is established in routine H/E sections and may be confirmed by immunohistochemistry, but there are atypical variants of DF with less clear histological differences and non-conclusive immunohistochemical results. In those cases, electron microscopy studies may be useful in establishing the diagnosis. The authors describe in detail the ultrastructural characteristics of 38 cases of DFSP and 10 cases of DF. The objective was to establish the ultrastructural features for differential diagnosis, and to identify the possible histogenesis of both neoplasms. DFSP is formed by stellate or spindled cells with long, slender, ramified cell processes joined by primitive junctions. Subplasmalemmal densities were frequently seen in the processes. Another common finding was the presence of multivesicular buds (MVB), peculiar structures that contain microvesicles abutting from the cell membrane. In contrast, DF is characterized by a proliferation of multiple capillary vessels with prominent endothelium and a perivascular population of ovoid or spindled cells devoid of cell processes. These latter cells featured intracytoplasmic lipid material (p < .001), infrequent subplasmalemmal densities (p < .001), and absence of MVB (p < .001). With the ultrastructural characteristics and the constant expression of CD34 in DFSP, a probable origin in dermal dendrocytes is postulated for this tumor. The histogenesis of DF is less clear, but an origin from FXIIIa modified perivascular dermal dendrocytes is proposed.

Spontaneous expression of embryonic factors and p53 point mutations in aged mesenchymal stem cells: a model of age-related tumorigenesis in mice

Aging is the single most common risk factor for cancer. Peripheral and marrow-derived stem cells are long lived and are candidate cells for the cancer-initiating cell. Repeated rounds of replication are likely required for accumulation of the necessary genetic mutations. Based on the facts that mesenchymal stem cells (MSC) transform with higher frequency than other cell types, and tumors in aged C57BL/6 mice are frequently fibrosarcomas, we used a genetically tagged bone marrow (BM) transplant model to show that aged mice develop MSC-derived fibrosarcomas. We further show that, with aging, MSCs spontaneously transform in culture and, when placed into our mouse model, recapitulated the naturally occurring fibrosarcomas of the aged mice with gene expression changes and p53 mutation similar to the in vivo model. Spontaneously transformed MSCs contribute directly to the tumor, tumor vasculature, and tumor adipose tissue, recruit additional host BM-derived cells (BMDC) to the area, and fuse with the host BMDC. Unfused transformed MSCs act as the cancer stem cell and are able to form tumors in successive mice, whereas fusion restores a nonmalignant phenotype. These data suggest that MSCs may play a key role in age-related tumors, and fusion with host cells restores a nonmalignant phenotype, thereby providing a mechanism for regulating tumor cell activity.

Medallion-like dermal dendrocyte hamartoma

Medallion-like dermal dendrocyte hamartomas are rare congenital cutaneous lesions, with only three occurrences reported in the English language literature. They present at birth as asymptomatic circular, oval, or triangular well-circumscribed, atrophic patches. Typically, they have an erythematous or yellow-brown hue and a characteristic pliable, wrinkled surface; subtle telangiectases may also be appreciated. They may be misdiagnosed as atrophoderma, cutis aplasia, or anetoderma. All reported patients have been female. Characteristic histologic findings include epidermal atrophy and the presence of a CD34-positive spindle cell proliferation in the dermis. This spindle cell proliferation represents a population of dermal dendrocytes, which are bone marrow-derived cells that are believed to function as antigen-presenting cells that contribute to the function of the skin immune system. Little is known about the pathophysiology of medallion-like dermal dendrocyte hamartomas. We present a patient with this entity and review similar presentations reported in the literature.

Stromelysin-3 expression in the differential diagnosis of dermatofibroma and dermatofibrosarcoma protuberans: comparison with factor XIIIa and CD34

BACKGROUND

The distinction between dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP) is a well-known challenge for dermatopathologists. Immunohistochemical stains have been used to augment routine histological examination to aid in differentiating DF from DFSP. Stromelysin-3 (ST3) is a member of the matrix metalloproteinase (MMP) family, MMP-11, which is expressed in the skin during wound healing and in the stroma of basal cell carcinoma. Recent studies demonstrated that DFs expressed ST3, whereas DFSPs were only rarely ST3 positive.

OBJECTIVES

To assess the expression of ST3 in DF and DFSP and to ascertain whether ST3 is superior to factor XIIIa or CD34 in differentiating DF from DFSP, by comparison with factor XIIIa and CD34 expression.

METHODS

Immunohistochemical staining was performed on 23 cases of DF and 17 cases of DFSP, using antibodies to ST3, factor XIIIa and CD34.

RESULTS

ST3 was expressed in all cases of DF (23 of 23) but only one case showed weakly positive staining in DFSP (one of 17). The mean +/- SD ST3 immunohistochemistry (IHC) score in DF was 4.52 +/- 0.67. The sensitivity of ST3 was 100% and the specificity was 94%. Factor XIIIa was expressed in all cases of DF (23 of 23) and in five of the 17 DFSPs. The mean +/- SD factor XIIIa IHC score in the DFs was 4.43 +/- 0.73. The sensitivity of factor XIIIa was 100% and the specificity was 71%. CD34 was expressed in four of the 23 DFs and 16 of the 17 DFSPs. The mean +/- SD CD34 IHC score in the DFSPs was 4.41 +/- 1.37. The sensitivity of CD34 was 94% and the specificity was 83%.

CONCLUSIONS

Immunohistochemical staining with a commercial anti-ST3 antibody can be successfully carried out in routine dermatopathology. We confirmed that ST3 is a positive marker for DF and that ST3 staining might be more reliable than factor XIIIa staining in differential diagnosis of DF and DFSP. As the present study showed that ST3 was not absolutely negative in all cases of DFSP, the combination with CD34 immunostaining could make the distinction more reliable.

Dermatofibrosarcoma protuberans

Dermatofibrosarcoma protuberans (DFSP) is a soft tissue neoplasm of intermediate malignancy that is initially localized to the skin from where it can invade deep structures (fat, fascia, muscle and bone). It is the most frequent fibrohistiocytic tumor, comprising approximately 1.8 % of all soft tissue sarcomas and 0.1 % of all cancers. It has an estimated incidence of 0.8-5 cases per one million persons per year. Treatment of localized disease consists in complete surgical excision of the lesion by conventional surgery with wide margins (>3 cm) or by micrographic Mohs surgery. Although the cases of metastatic DFSP do not reach 5 % of the total, almost all of them appear after previous local relapses. The prognosis for metastatic cases is very poor with a survival of less than 2 years following detection of metastatic disease. Patients with locally advanced DFSP are not candidates for an initial radical surgical therapy therefore neoadyuvant treatment is required prior to surgery in order to reduce tumor burden. In this regard, chemotherapy and radiotherapy have not been highly efficacious so it is necessary to consider new alternatives. The demonstration of the oncogenic power of the translocation COL1A1-PDGFB in DFSP has allowed the successful introduction of drug therapy with antagonists of the PDGFB receptor for metastatic or locally advanced cases.