Cytogenetic and immunohistochemical evidence that giant cell fibroblastoma is related to dermatofibrosarcoma protuberans

Dermatofibrosarcoma Protuberans: An Updated Review of the Literature

Dermatofibrosarcoma protuberans (DFSP) is a rare proliferative condition representing skin sarcomas which is known to locally recur yet very rarely metastasizes. Its genetic background is a reciprocal translocation t(17;22)(q22;q13) that produces COL1A1-PDGFB gene fusion. Complete resection is the primary treatment. The aim of this review is to outline the pathogenesis, diagnosis, and management of DFSP. A clear-cut distinction between low-to-moderate-grade DFSP with excellent prognosis and high-grade fibrosarcomatous DFSP with a much worse prognosis is underlined. Malignant transformation within DFSP (or high histologic grade), older age, being female, large primary tumor size (≥10 cm), narrow surgical margins of excision (<3 cm), surgical margin positivity for tumor cells, short time to recurrence, numerous recurrences, tumor that was recently rapidly enlarging, and presence of pain in the tumor have all been proposed as clinicopathological risk factors for recurrence and metastasis. A tendency for local growth and local relapses of well- and moderately differentiated DFSPs is an argument for their surgical excision, possibly combined with reconstructive surgery, even in patients of advanced age. Another main point of this review is that cases of DFSP with fibrosarcomatous transformation are a challenge and require careful medical attention. Both anatomopathological evaluation of the presence of lymphovascular space invasion and sentinel lymph node biopsy at DFSP surgery merit further study.

Dermatofibrosarcoma Protuberans: Update on the Diagnosis and Treatment

Dermatofibrosarcoma protuberans (DFSP) is a slow growing, low- to intermediate-grade dermal soft-tissue tumor. It has a high local recurrence rate but low metastatic potential. It is characterized by a uniform spindle cell arrangement, classically with a storiform pattern and CD34 immunoreactivity. The histomorphology and immunophenotype overlap with a broad range of other neoplasms. The standard treatment is complete surgical excision. The surgical procedures include wide local excision (WLE) with tumor free margins, Mohs micrographic surgery (MMS) and amputation. Unresectable DFSPs are treated with radiation therapy and/or targeted therapy. DFSP has characteristic t(17; 22) (q22; q13), resulting in a COL1A1- PDGFB fusion transcripts in more than 90% of DFSPs. Molecular detection of the gene rearrangement or fusion transcripts is helpful for the diagnosis of patients with atypical morphology and for screening candidates for targeted therapy with tyrosine kinase inhibitors. The aims of the present review are to update the clinical presentation, tumorigenesis and histopathology of DFSP and its variants for diagnosis and differential diagnosis from other benign and malignant tumors, to compare the advantages and drawbacks of WLE and MMS, to propose the baseline for selecting surgical procedure based on tumor's location, size, stage and relationship with surrounding soft tissue and bone structures, and to provide a biologic rationale for the systemic therapy. We further propose a modified clinical staging system of DFSP and a surveillance program for the patients after surgical excision.

Soft Tissue Special Issue: Fibroblastic and Myofibroblastic Neoplasms of the Head and Neck

Fibroblastic and myofibroblastic neoplasms of the head and neck encompass a group of rare tumor types with often overlapping clinicopathologic features that range in biologic potential from benign to overtly malignant. Even neoplasms with no metastatic potential may provide significant therapeutic challenges in this region due to the unique anatomy of the head and neck. This review will cover the following entities, highlighting important clinical aspects of each neoplasm and then focusing on their characteristic histomorphology, immunophenotype, and molecular alterations: nodular and cranial fasciitis, fibrous hamartoma of infancy, nasopharyngeal angiofibroma, nuchal-type and Gardner fibromas, desmoid fibromatosis, dermatofibrosarcoma protuberans and giant cell fibroblastoma, solitary fibrous tumor, inflammatory myofibroblastic tumor, low-grade myofibroblastic sarcoma, infantile fibrosarcoma, low-grade fibromyxoid sarcoma, and sclerosing epithelioid fibrosarcoma. While some of these neoplasms characteristically arise in the head and neck, others are rarely described in this anatomic region and may therefore be particularly difficult to recognize. Distinction between these entities, however, is crucial, particularly as the molecular pathogenetic basis for these neoplasms are being rapidly elucidated, in some instances allowing for targeted therapeutic approaches.

Cutaneous soft tissue tumors: how do we make sense of fibrous and "fibrohistiocytic" tumors with confusing names and similar appearances?

In the 2018 World Health Organization Classification of Skin Tumors, a wide range of predominantly benign mesenchymal neoplasms are included in the fibroblastic, myofibroblastic, and "fibrohistiocytic" categories. By far the most common of these tumors is dermatofibroma (fibrous histiocytoma). There are many histologic variants of dermatofibroma, some of which (cellular, aneurysmal, and atypical) are associated with a higher risk of local recurrence; these variants may be mistaken for more aggressive tumor types, including sarcomas. Furthermore, distinguishing among the fibrous and "fibrohistiocytic" tumors can be a diagnostic challenge, given their sometimes-similar histologic appearances and confusing nomenclature. Immunohistochemistry and molecular genetic assays play a relatively limited role in the diagnosis of these tumor types, with notable exceptions (i.e., epithelioid fibrous histiocytoma and dermatofibrosarcoma protuberans). Proper recognition of dermatofibrosarcoma protuberans is critical, since this tumor type is associated with locally aggressive behavior; transformation to the fibrosarcomatous variant brings metastatic potential. In recent years, understanding of the molecular pathogenetic basis for cutaneous mesenchymal neoplasms has increased dramatically, with the discovery of gene rearrangements in some of these tumor types. In this review, the histologic features of the most common fibrous and "fibrohistiocytic" cutaneous mesenchymal neoplasms will be discussed, as well as recently identified molecular genetic alterations.

Contributions of Dr. Louis "Pepper" Dehner to the art of cutaneous pathology, the first pediatric dermatopathologist

Dr. Louis "Pepper" Dehner has been one of the most influential surgical pathologists of the last century. Authoring more than 450 publications, he is the premier modern pediatric pathologist. Perhaps, an area that he is less recognized and in which we would like to describe his contributions, is his role as a creator of the art of pediatric dermatopathology. Dr. Dehner has had at least 50 major publications describing, discovering, and orienting the discipline in the fields of fibrohistiocytic disorders of childhood, vascular tumors, and histiocytosis among many others. Dr. Dehner has clearly manifested that while many similarities between adult and pediatric surgical pathology exist, "children get different diseases." It is because of his mindful analysis and translation of the clinico-pathologic and biologic correlative between specific entities and advances in the field he has made that we are honored to describe some of his contributions to this particular area.

Recurrent giant cell fibroblastoma: Malignancy predisposition in Kabuki syndrome revisited

Kabuki syndrome is a genetic condition characterized by distinctive facial phenotype, mental retardation, and internal organ malformations. Mutations of the epigenetic genes KMT2D and KDM6A cause dysregulation of certain developmental genes and account for the multiple congenital anomalies of the syndrome. Eight cases of malignancies have been reported in young patients with Kabuki syndrome although a causative association to the syndrome has not been established. We report a case of a 12-year-old girl with Kabuki syndrome who developed a tumor on the right side of her neck. A relapsing tumor 19 months after initial excision, proved to be giant cell fibroblastoma. Τhis is the first report of giant cell fibroblastoma -a rare tumor of childhood- in a patient with Kabuki syndrome.

Selected Lesions Featuring Giant Cells

Many neoplasms of the soft tissues feature giant cells, but this article covers entities in which giant cells are a striking feature. Specifically, we consider tenosynovial giant cell tumor (localized and diffuse types; giant cell tumor of tendon sheath, and pigmented villonodular tenosynovitis), reticulohistiocytoma, juvenile xanthogranuloma, giant cell fibroblastoma (a variant form of dermatofibrosarcoma protuberans), giant cell angiofibroma (which is essentially a giant cell-rich form of solitary fibrous tumor), and phosphaturic mesenchymal tumor.

A genetic dichotomy between pure sclerosing epithelioid fibrosarcoma (SEF) and hybrid SEF/low-grade fibromyxoid sarcoma: a pathologic and molecular study of 18 cases

Sclerosing epithelioid fibrosarcoma (SEF) is a rare soft tissue tumor exhibiting considerable morphologic overlap with low-grade fibromyxoid sarcoma (LGFMS). Moreover, both SEF and LGFMS show MUC4 expression by immunohistochemistry. While the majority of LGFMS cases are characterized by a FUS-CREB3L1 fusion, both FUS-CREB3L2 and EWSR1-CREB3L1 fusions were recently demonstrated in a small number of LGFMS and SEF/LGFMS hybrid tumors. In contrast, recent studies pointed out that SEF harbor frequent EWSR1 rearrangements, with only a minority of cases showing FUS-CREB3L2 fusions. In an effort to further characterize the molecular characteristics of pure SEF and hybrid SEF/LGFMS lesions, we undertook a clinicopathologic, immunohistochemical and genetic analysis of a series of 10 SEF and 8 hybrid SEF/LGFMS tumors. The mortality rate was similar between the two groups, 44% within the pure SEF group and 37% in the hybrid SEF/LGFMS with a mean overall follow-up of 66 months. All but one pure SEF and all hybrid SEF/LGFMS-tested cases showed MUC4 immunoreactivity. The majority (90%) of pure SEF cases showed EWSR1 gene rearrangements by fluorescence in situ hybridization with only one case exhibiting FUS rearrangement. Of the nine EWSR1 positive cases, six cases harbored CREB3L1 break-apart, two had CREB3L2 rearrangement (a previously unreported finding) and one lacked evidence of CREB3L1/2 abnormalities. In contrast, all hybrid SEF/LGFMS tumors exhibited FUS and CREB3L2 rearrangements. These results further demarcate a relative cytogenetic dichotomy between pure SEF, often characterized by EWSR1 rearrangements, and hybrid SEF/LGFMS, harboring FUS-CREB3L2 fusion; the latter group recapitulating the genotype of LGFMS.

Nonepithelial skin tumors with multinucleated giant cells

Recognition of the different types of multinucleated giant cells in neoplastic and pseudotumoral lesions of the skin may be helpful in the differential diagnosis of these tumors. In this review, we will analyze the different types of multinucleated giant cells that can be found in nonepithelial cutaneous tumors and, more importantly, the clinicopathological context in which they are found. Touton giant cells are typically present in juvenile xanthogranuloma, necrobiotic xanthogranuloma, and some subtypes of xanthomas. Giant cells with a ground glass appearance are typically present in the solitary reticulohistiocytoma and multicentric reticulohistiocytosis. Osteoclast-like cells are found in giant cell tumors (GCT) of soft parts, plexiform fibrohistiocytic tumor, and atypical fibroxanthoma. Floret-like cells are present in giant cell fibroblastoma, pleomorphic lipoma, multinucleate cell angiohistiocytoma, and giant cell collagenoma.

Fibrohistiocytic tumors and related neoplasms in children and adolescents

Fibrohistiocytic tumors (FHTs) in children and adolescents range from the benign fibrous histiocytoma, or dermatofibroma, to a variety of intermediate and malignant neoplasms, such as dermatofibrosarcoma protruberans and high-grade undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma). Those tumors as a group are comprised of fibroblasts, myofibroblasts, and histiocytes-dendritic cells with a variably prominent inflammatory infiltrate consisting of lymphocytes and eosinophils. Dendritic cells are also a major constituent of another group of neoplasms that include Langerhans cell histiocytosis, follicular and interdigitating cell sarcomas, and juvenile xanthogranuloma. These latter tumors are considered in this discussion for the sake of differential diagnosis and their possible histogenetic relationship to FHTs. Recent studies have suggested that the relationship between the fibroblast and histiocyte in the FHTs may reflect the intrinsic capacity to transdifferentiate from one to the other morphologic and functional state. The so-called "facultative fibroblast," as a cell with fibroblastic and histiocytic properties, was discussed in the context of the fibrous xanthoma 50 years ago. Possibly the entire histogenetic concept of FHTs should be reconsidered in light of current studies.

Advances in molecular characterization and targeted therapy in dermatofibrosarcoma protuberans

The molecular pathogenesis of dermatofibrosarcoma protuberans (DFSP) involves distinctive rearrangement of chromosomes 17 and 22 leading to formation of the COL1A1-PDGFB fusion gene. The knowledge of molecular events underlying development of DFSP resulted in the implementation of targeted therapy with imatinib—a tyrosine kinase inhibitor (TKI), to the clinical practice. The striking efficacy of imatinib in advanced cases of DFSP has been demonstrated in a few clinical trials. Thus, imatinib is currently considered the gold standard in the treatment of inoperable and/or metastatic and/or recurrent cases of DFSP. Therapy with imatinib may potentially facilitate resection or decrease possible disfigurement related to radical surgical procedure. Following partial response on imatinib significant percentage of patients may be rendered free of the disease by surgery of the residual tumor.

Imatinib mesylate in advanced dermatofibrosarcoma protuberans: pooled analysis of two phase II clinical trials

PURPOSE

Dermatofibrosarcoma protuberans (DFSP) is a dermal sarcoma typically carrying a translocation between chromosomes 17 and 22 that generates functional platelet-derived growth factor B (PDGFB).

PATIENTS AND METHODS

Two distinct phase II trials of imatinib (400 to 800 mg daily) in patients with locally advanced or metastatic DFSP were conducted and closed prematurely, one in Europe (European Organisation for Research and Treatment of Cancer [EORTC]) with 14-week progression-free rate as the primary end point and the other in North America (Southwest Oncology Group [SWOG]) with confirmed objective response rate as the primary end point. In the EORTC trial, confirmation of PDGFB rearrangement was required, and surgery was undertaken after 14 weeks if feasible. The SWOG study confirmed t(17;22) after enrollment.

RESULTS

Sixteen and eight patients were enrolled onto the EORTC and SWOG trials, respectively. Tumor size ranged from 1.2 to 49 cm. DFSP was located on head/neck, trunk, and limb in seven, 11, and six patients, respectively, and was classic, pigmented, and fibrosarcomatous DFSP in 13, one, and nine patients, respectively. Metastases were present in seven patients (lung involvement was present six patients). Eleven patients (4%) had partial response as best response, and four patients had progressive disease as best response. Median time to progression (TTP) was 1.7 years. Imatinib was stopped in 11 patients because of progression, one patient because of toxicity, and two patients after complete resection of disease. Median overall survival (OS) time has not been reached; 1-year OS rate was 87.5%.

CONCLUSION

Imatinib is active in DFSP harboring t(17;22) including fibrosarcomatous DFSP, with objective response rate approaching 50%. Response rates and TTP did not differ between patients taking 400 mg daily versus 400 mg twice a day.

The impact of advances in molecular genetic pathology on the classification, diagnosis and treatment of selected soft tissue tumors of the head and neck

Recent advances in molecular pathology have had a significant impact on the diagnosis, classification, and treatment of soft tissue tumors. The practical application of these discoveries promises to assist greatly in the evaluation and treatment of soft tissue neoplasms in the head and neck region-an area characterized by exceedingly complex anatomy that often restricts the ample sampling of lesions and complete surgical resection. This reviews details some ways in which molecular techniques have strengthened conventional diagnostic and management approaches to low-grade fibromyxoid sarcoma, angiomatoid (malignant) fibrous histiocytoma, and dermatofibrosarcoma protuberans, all of which may involve the head and neck region.

Giant cell fibroblastoma of the vulva at the site of a previous fibroepithelial stromal polyp: a case report

BACKGROUND

Giant cell fibroblastoma (GCF) is an unusual soft tissue tumor, occurring predominantly in infants and children, and rarely in adults. Giant cell fibroblastoma develops de novo in the dermis or subcutis with a predilection for the extremities, the abdominal and chest walls, umbilical and inguinal regions.

CASE

A GCF arose at the same site (labium majus of vulva) as a previous cellular fibroepithelial stromal polyp in a 28-year-old woman.

CONCLUSION

We report a case of GCF of the vulva, an unreported site.

Detection of COL1A1 -PDGFB fusion transcripts and platelet-derived growth factor α and β receptors in giant cell fibroblastoma of the postsacrococcygeal region

We describe a 2-year-old girl with recurrent giant cell fibroblastoma (GCF) of the postsacrococcygeal region. Both the initial and recurrent tumours contained solid and angiectoid areas. The former was composed of loosely arranged wavy spindle cells and giant cells with a well-vascularized myxoid to collagenous stroma. The angiectoid spaces were often lined by multinucleated giant cells. Immunohistochemically, the tumour cells and small vessels in the tumour tissue were positive for platelet-derived growth factor (PDGF) alpha and beta receptors. Molecular analysis revealed fusion of collagen type Ialpha1 exon 26 with PDGF-B chain exon 2 that induced unscheduled production of PDGF-BB. These findings suggest that PDGF and its receptors significantly contribute to the development of GCF in both an autocrine and a paracrine manner.

Childhood dermatofibrosarcoma protuberans: role of preoperative imaging

Dermatofibrosarcoma protuberans (DFSP) is especially challenging to recognize and diagnose in children. Prompt and definitive treatment is essential based on the tumor's high rate of recurrence. Our purpose is to increase physician awareness and recognition of DFSP in the pediatric population with the largest case series of childhood DFSP to our knowledge thus reported in the literature. We also propose that magnetic resonance imaging (MRI) may be useful in the preoperative assessment. The records of 10 patients with primary DFSP between the ages of 8 months and 16 years were reviewed. Only 1 of 10 patients was given the correct diagnosis at the initial medical evaluation. Of the 10 cases, 5 were congenital. The average delay in diagnosis was 5 years. Of the patients, 5 had preoperative MRI to delineate the size and extent of the tumor. In the two cases with the largest tumors preoperative MRI significantly altered surgical planning and execution. Thus, preoperative MRI may be helpful in planning for successful surgical clearance of large tumors and preventing local recurrence. All 10 cases were treated with Mohs micrographic surgery and no recurrences were noted with a follow-up range of 6 weeks to 17 years.

Cutaneous and Subcutaneous Fibrohistiocytic Tumors of Intermediate Malignancy

The fibrohistiocytic tumors of intermediate malignancy are uncommon mesenchymal tumors, which typically occur in the skin and subcutis and which may pose significant problems for the dermatopathologist. This article reviews the clinical, histopathologic, and genetic features of dermatofibrosarcoma protuberans, giant cell fibroblastoma, angiomatoid (malignant) fibrous histiocytoma, plexiform fibrous histiocytoma, and soft tissue giant cell tumor (of low malignant potential). The differential diagnosis of these tumors with a variety of benign and fully malignant cutaneous soft tissue neoplasms is discussed.

Genetics of dermatofibrosarcoma protuberans family of tumors: from ring chromosomes to tyrosine kinase inhibitor treatment

Dermatofibrosarcoma protuberans (DP) is a rare, slow-growing, infiltrating dermal neoplasm of intermediate malignancy, made up of spindle-shaped tumor cells often positive for CD34. The preferred treatment is wide surgical excision with pathologically negative margins. At the cytogenetic level, DP cells are characterized by either supernumerary ring chromosomes, which have been shown by using fluorescence in situ hybridization techniques to be derived from chromosome 22 and to contain low-level amplified sequences from 17q22-qter and 22q10-q13.1, or t(17;22), that are most often unbalanced. Both the rings and linear der(22) contain a specific fusion of COL1A1 with PDGFB. Similar to other tumors, the COL1A1-PDGFB fusion is occasionally cryptic, associated with complex chromosomal rearrangements. Although rings have been mainly observed in adults, translocations have been reported in all pediatric cases. DP is therefore a unique example of a tumor in which (i) the same molecular event occurs either on rings or linear translocation derivatives, (ii) the chromosomal abnormalities display an age-related pattern, and (iii) the presence of the specific fusion gene is associated with the gain of chromosomal segments, probably taking advantage of gene dosage effects. In all DP cases that underwent molecular investigations, the breakpoint localization in PDGFB was found to be remarkably constant, placing exon 2 under the control of the COL1A1 promoter. In contrast, the COL1A1 breakpoint was found to be variably located within the exons of the alpha-helical coding region (exons 6-49). No preferential COL1A1 breakpoint and no correlation between the breakpoint location and the age of the patient or any clinical or histological particularity have been described. The COL1A1-PDGFB fusion is detectable by multiplex RT-PCR with a combination of forward primers designed from a variety of COL1A1 exons and one reverse primer from PDGFB exon 2. Recent studies have determined the molecular identity of "classical" DP, giant cell fibroblastoma, Bednar tumor, adult superficial fibrosarcoma, and the granular cell variant of DP. In approximately 8% of DP cases, the COL1A1-PDGFB fusion is not found, suggesting that genes other than COL1A1 or PDGFB might be involved in a subset of cases. It has been proposed that PDGFB acts as a mitogen in DP cells by autocrine stimulation of the PDGF receptor. It is encouraging that inhibitory effects of the PDGF receptor tyrosine kinase antagonist imatinib mesylate have been demonstrated in vivo; such targeted therapies might be warranted in the near future for treatment of the few DP cases not manageable by surgery.

Nodular sclerotic change in dermatofibrosarcoma protuberans: a potential diagnostic problem

Nodular sclerotic change in dermatofibrosarcoma protuberans (DFSP) is not a well-recognized event. Sclerotic change is reported in three patients with DFSP: a 33-year-old woman with a left subclavian mass, a 29-year-old woman with a mass on the left crus and a 31-year-old man with a mass on the left cheek. Histologically, lesions consisted of two types of feature, one type being typical of DFSP and the other being rich in collagen. In the first patient, each type formed a distinct compartment, each of which contained scattered cells containing melanin pigment. In the second patient, foci with typical DFSP histology were distributed within the collagen-rich area and also formed a substantial compartment in the periphery of the lesion, with pigmented cells being distributed mainly in and around the cellular area. In the third patient, the collagenous area occupied about half of the lesion. There was no pigmentation. In all three cases the collagen-rich area contained sparsely distributed fibroblast-like cells that stained positive with CD34. Sclerotic change in DFSP could cause substantial difficulty in diagnosis if the biopsy material were partial and small. The clinical history and knowledge about the existence of this kind of histological variation in DFSP are important.

Dermatofibrosarcoma protuberans, giant cell fibroblastoma, and hybrid lesions in children: clinicopathologic comparative analysis of 28 cases with molecular data--a study from the French Federation of Cancer Centers Sarcoma Group

The clinicopathologic and immunohistochemical features of 28 dermatofibrosarcoma protuberans (DFSP), giant cell fibroblastomas (GCFs), and hybrid lesions occurring in children are presented, including molecular data for seven of them. There were 19 pure adult-type DFSP (9 male and 10 female patients aged between a few days [neonate] and 13 years, median 7 years), 5 pure GCF (all males aged from 2 to 8 years, median 4 years), and 4 hybrid tumors (all males aged from 1 to 4 years, median 2.5 years). Tumor locations in pure adult-type DFSP included the trunk (6) and lower (11) and upper (2) limbs. Pure GCFs were observed on the trunk (4) and knee (1), and hybrid lesions on the trunk (2) and lower (1) and upper (1) extremities. Tumor size (n = 20) ranged from 0.6 to 5 cm (median 2 cm). Histologically, pure DFSP presented as monotonous and infiltrative, low-grade, dermal/hypodermal storiform spindle cell proliferations, sparing adnexal structures. GCF showed a dense fibrous to myxoid matrix containing slender wavy spindle cells and multinucleated giant stromal cells often lining angiectoid spaces. Hybrid lesions showed varying combinations of DFSP and GCF areas. Mitotic activity ranged from 1 to 3 mitoses per 10 high power fields. All tumors were diffusely positive for vimentin and CD34 but negative for smooth muscle actin, desmin, epithelial membrane antigen, and cytokeratins; one pure adult-type DFSP was also S-100 protein positive; <1% of nuclei were Ki67 (Mib-1) positive. One karyotyped adult-type DFSP showed an unbalanced t(17;22) (q22;q13) translocation. Multiplex RT-PCR analysis and sequencing of PCR products in seven cases showed gene fusion transcripts in two pure DFSP, two pure GCFs, and one hybrid lesion. Results were uncertain in one pure GCF; one adult-type DFSP was negative. Treatment procedures were known for 27 patients, consisting of 16 wide excisions and 11 marginal excisions. Follow-up information on 15 widely excised tumors (median 24 months; range 5-144 months) showed no recurrence. Five of six marginally excised lesions with available follow up recurred 2 months to 6 years (median 2 years) after initial surgery; all but one were cured by wide reexcision. None of the tumors metastasized. In conclusion, this study emphasizes 1) the occurrence of adult-type DFSP in children, 2) the close relationship between DFSP and GCF clinically, histologically, and molecularly, 3) the excellent prognostic of these lesions if widely excised, and 4) the diagnostic usefulness of RT-PCR analyses in detecting the gene fusion transcripts resulting from the t(17;22) (q22;q13) in paraffin-embedded tissues.

Giant cell fibroblastoma in a 3-year-old boy

Giant cell fibroblastoma (GCF) is a rare soft tissue tumor most often discovered during the first two decades of life. We present a case of a 3-year-old boy with a history of a recurrent lesion in the knee, the tumor growth progressively and enlarged to 2.1 cm in the previous two years before diagnosis. It involved the subcutaneous tissue, had infiltrative borders and extended into the superficial dermis. The tumor was surgically excised with free margins. There was no evidence of local recurrence, and a metastatic workup was negative after 10 years of follow up. We review herein the clinicopathologic features, histogenesis, differential diagnosis and relationship to dermatofibrosarcoma protuberans (DFSP).

Multiple spindle cell lipomas and dermatofibrosarcoma protuberans within a single patient: evidence for a common neoplastic process of interstitial dendritic cells?

This case report describes a 48-year-old man with multiple spindle cell lipomas of the neck and a dermatofibrosarcoma protuberans (DFSP) with fibrosarcomatous transformation of the chest. The presence of familial and nonfamilial multiple spindle cell lipomas within a single patient is a rare event, with only two reports in the current literature. This case represents the first report of multiple spindle cell lipomas occurring in association with a DFSP. It is of particular interest in that both spindle cell lipoma and DFSP represent, at least in part, neoplastic proliferations of CD34(+) spindled cells. The exact nature and differentiation of these spindled cells remains controversial, but prior studies have suggested that they could represent neoplastic interstitial dendritic cells. The association of DFSP and spindle cell lipoma within this single patient suggests that these two tumors (and their histologic variants) may well be linked, conceptually, as neoplastic proliferations of CD34(+) interstitial dendritic cells.

Dermatofibrosarcoma protuberans: a clinicopathological study of 20 cases

AIM

To review the dinical and histological data of 20 cases of dermatofibrosarcoma protuberans presenting at two dermatology centres in Lisbon from 1978 to 1998.

PATIENTS AND METHODS

The 20 subjects comprised nine males and 11 females ranging in age from 25 to 79 years, with highest frequency of subjects in the 30-50 year olds. We reviewed the clinical features, histopathological aspects, including morphologic variants and immunohistochemical studies.

RESULTS

Median age at diagnosis was 51 years and the trunk was the most frequent location. The characteristic histologic storiform pattern was seen in all cases. Three subjects presented fibrosarcomatous areas, one with myoid differentiation and another with multinucleated giant cells. Immunohistochemical stains revealed CD34 expression in the 18 specimens tested, FXIIIa was negative, and these two antigens proved important for the differential diagnosis of this neoplasm. Local wide excision was performed in 13 cases and seven patients underwent Moh's micrographic surgery. Follow-up ranged from 2 months to 17 years and three recurrences were recorded, two following classical surgery and one after Moh's surgery; there was no difference in the rate of local recurrence (15%) for the two kinds of treatment in our series.

COL1A1-PDGFB gene fusion demonstrates a common histogenetic origin for dermatofibrosarcoma protuberans and its granular cell variant

Granular cell variant of dermatofibrosarcoma protuberans is very rare with only one report of two cases. We report a new case in which we demonstrated the presence of the dermatofibrosarcoma protuberans-specific COL1A1-PDGFB fusion from paraffin-embedded tissue. This case analysis demonstrated the utility of molecular genetics as a powerful tool for the diagnosis of atypical forms of dermatofibrosarcoma protuberans.

Fine-needle aspiration cytology of giant cell fibroblastoma: case report and review of the literature

Giant cell fibroblastoma is an uncommon soft tissue neoplasm occurring in childhood. It appears to be the juvenile form of dermatofibrosarcoma protuberans, with which it shares some histologic, cytogenetic, and immunohistochemical features. We report, to our knowledge, the second description of the cytologic features of giant cell fibroblastoma. The present case represents a recurrent lesion in the soft tissues of the scrotum of a 17-yr-old male. The aspirate produced moderately cellular smears containing mononuclear cells, usually lying singly, but occasionally forming clusters. The majority of the individual cells possessed scanty bipolar cytoplasm or were devoid of cytoplasm. The nuclei were bland, with small nucleoli. Nuclear membranes frequently contained notches, creases, or folds. Small fragments of metachromatic stroma were present in the background and were often associated with small aggregates of cells. Rare multinucleated giant cells containing bland oval or basillary-shaped nuclei were admixed with the spindle-cell component. Necrosis and mitotic figures were not a component of the smears. Surgical resection of the mass confirmed the diagnosis of giant cell fibroblastoma. We review the characteristic cytologic features of giant cell fibroblastoma and compare them with other soft tissue tumors in the differential diagnosis.

Fusion of COL1A1 exon 29 with PDGFB exon 2 in a der(22)t(17;22) in a pediatric giant cell fibroblastoma with a pigmented Bednar tumor component. Evidence for age-related chromosomal pattern in dermatofibrosarcoma protuberans and related tumors

In contrast with classic dermatofibrosarcoma protuberans (DP), genetic information about the juvenile or pigmented variant forms of DP, so-called giant cell fibroblastoma (GCF) and Bednar tumor (BT), is limited. In the sole karyotyped case of BT a supernumerary ring containing chromosomes 17 and 22 sequences, similar to DP rings, was reported, whereas in three GCF cases, t(17;22) or der(22)t(17;22) with COL1A1-PDGFB fusion involving exons 11, 40, and 47, respectively, have been described. Here, we report the first cytogenetic and molecular analysis of a tumor from a 5-year-old child that contained both GCF and BT components. The karyotype and molecular analyses confirmed the common histogenetic origin between DP, GCF, and BT in showing the presence of a der(22)t(17;22) fusing the COL1A1 exon 29 to PDGFB exon 2. Because COL1A1 exon 29 has been involved previously in gene fusion with PDGFB exon 2 in several cases of adult or infantile DP presenting either t(17;22) or ring chromosomes, our results support the concept that DP, GCF, and BT are morphologic variants of a same entity, rather than distinct tumors. Of interest, our findings give prominence to the relation between patient age and the chromosomal rearrangement pattern in DP and related tumors. Whereas only a few adult DP cases presented with translocations, all the infantile cases, either DP, GCF, or mixed BT-GCF, as shown here, contained translocation derivatives but not ring chromosomes. All the ring chromosomes were observed in adult cases. With respect to cytogenetic studies, DP, GCF, and BT appear to be a unique model for age-related chromosomal rearrangement progression.

Giant cell fibroblastoma in a child misdiagnosed as a dermatofibroma

We report a 9-year-old African-American boy with a giant cell fibroblastoma of the shoulder that was incorrectly diagnosed as a keloid and dermatofibroma. Initial misdiagnosis led to a delay of 4 years in the correct diagnosis, with the tumor producing significant local destruction. We review herein the clinical manifestations, histologic findings, histogenesis, relationship to dermatofibrosarcoma protuberans (DFSP), treatment, and differential diagnosis of giant cell fibroblastoma (GCF). This information is important in correctly diagnosing this uncommon, benign, but locally aggressive and recurrent tumor of childhood. The clinician should consider GCF and DFSP when the pathologic diagnosis of dermatofibroma is made in lesions more than 2 cm in diameter, or when this diagnosis is made in a prepubertal child.

Giant cell angioblastoma: three additional occurrences of a distinct pathologic entity

Giant cell angioblastoma was described previously in a single case report as a congenital soft-tissue tumor with a unique morphology. In the current report, we describe three cases of giant cell angioblastoma found in three infants; one case was congenital and located in the hand, one appeared neonatally in the palate, and one on the scalp of an infant. Clinical findings and results of light microscopy, immunohistochemistry, and electron microscopy were evaluated. All tumors were ulcerated; the hand and palate tumors also infiltrated soft tissue and bone. They exhibited a solid, nodular, and plexiform proliferation of oval-to-spindle cells with a frequent striking, concentric aggregation around small vascular channels. These cells had characteristics of undifferentiated mesenchymal cells, fibroblasts, myofibroblasts, and pericytes. Co-mingled with these cells were large mononuclear and multinucleate giant cells with histiocytic features. The palatal giant cell angioblastoma, excised with positive margins, was managed with interferon-alpha and showed no progression after nearly 5 years. The hand tumor diminished in size after management with interferon-alpha, was subtotally excised, and did not progress after 27 months. Follow-up data are unavailable for the patient with the scalp lesion. Our findings validate the classification of giant cell angioblastoma as a distinct and rare entity that is locally infiltrative but slow growing. The morphology and diverse cellular differentiation are consistent with an unusual form of neoplastic angiogenesis.

Contribution of molecular genetic data to the classification of sarcomas

Many sarcomas are characterized by specific recurrent chromosomal translocations which provide powerful diagnostic tumor markers. Since 1992, the genes involved by almost all of these translocations have been cloned, inaugurating a new era in the study of sarcomas. At the biological level, these chromosomal translocations produce highly specific gene fusions, usually encoding aberrant chimeric transcription factors. Clinically, the correlation of these translocation-derived genetic markers and discrete histopathologic entities has been remarkable. Fusion gene detection has confirmed and refined the nosology of several sarcoma groups. The overall effect has been to strengthen certain pathological concepts rather than to revolutionize. The focus of this brief review is the recent impact that the cytogenetic and molecular detection of these translocations has had on sarcoma diagnosis and classification.

Congenital and childhood dermatofibrosarcoma protuberans: a case report and review of the literature

Dermatofibrosarcoma protuberans (DFSP) occurs most commonly on the trunk, affects all races, and often develops between the second and fifth decades of life. It is uncommon in childhood and is sometimes mistaken for a vascular lesion, as it often presents as a blue macule or small nodule. Review of the English literature revealed approximately 152 cases of DFSP developing before 16 years of age and only 19 claimed congenital cases. A case of congenital dermatofibrosarcoma protuberans is presented with a literature review and discussion of congenital and childhood presentations of the tumor.

A giant cell angiofibroma involving 6q

Giant cell angiofibroma, a recently proposed new clinicopathological entity, arises exclusively in the orbit in adults and histologically exhibits features intermediate between those of giant cell fibroblastoma and solitary fibrous tumor. In a typical case of giant cell angiofibroma, abnormalities of chromosome 6 with a common pattern involving 6q13 were detected together with various other chromosomal aberrations. To our knowledge, this is the first reported case of giant cell angiofibroma demonstrating chromosomal abnormalities.

Differential expression of CD34 and Ki-M1p in pleomorphic fibroma and dermatofibroma with monster cells

Pleomorphic fibroma (PF) and dermatofibroma with monster cells (DFMC) are characterized by the presence of numerous cells with large atypical nuclei. Despite cytologic similarities, the two entities are likely to be unrelated, but their histogenesis is poorly understood. In this study, we examined six cases of PF and eleven cases of DFMC by immunohistochemistry using antibodies against vimentin, alpha-smooth muscle actin, S-100 protein, CD34, factor XIIIa, and the pan-monocytic marker Ki-M1p. Strong vimentin expression was seen in all tumors, whereas none of them expressed S-100 protein. PF consistently exhibited CD34 staining but appeared to be depleted of Ki-M1p positive cells compared with the surrounding normal skin. Conversely, all cases of DFMC contained numerous Ki-M1p positive cells including atypical multinucleate cells, but virtually no CD34 reactivity was observed. A weak staining for alpha-smooth muscle actin was occasionally seen in a subset of the cells of both entities. Our results indicate that PF and DFMC are histogenetically distinct entities that may arise from two different types of dermal dendritic cells defined by their reactivity for CD34 and Ki-M1p, respectively. Immunohistochemistry using these two antibodies permits an easy and reliable discrimination between PF and DFMC.

A progression to dermatofibrosarcoma protuberans with a fibrosarcomatous component: a special reference to the chromosomal aberrations

Dermatofibrosarcoma protuberans (DFSP) with fibrosarcomatous areas (DFSP-FS) is differentiated from ordinary DFSP by its unfavourable prognosis. We carried out sequential analysis of numerical chromosomal abnormalities in two cases of DFSP during their progression to metastatic disease with FS areas (DFSP-M-FS). They were compared with nine cases of ordinary DFSP and three cases of DFSP-FS, but without metastases. Numerical chromosomal changes were examined by fluorescence in situ hybridization (FISH) using alpha-satellite centromeric probes for chromosomes 1, 8, 11 and 17. Numerical imbalances of chromosome 1 were not clarified. A gain of chromosome 8 was demonstrated in the two cases of DFSP-M-FS. A gain of chromosome 11 was observed in one of the two cases of DFSP-M-FS and in one case of DFSP-FS. A gain of chromosome 17 was demonstrated in both metastatic tumours and in recurrent tumours in two cases of DFSP-M-FS, in addition to two cases of DFSP-FS and four cases of ordinary DFSP with recurrent tumours or large tumours. This study raised the hypothesis that a gain of chromosome 17 developed in recurrent or large-sized DFSP, which occurs in high-risk groups with the possibility of a progression to FS.

The pathological distinction between "deep penetrating" dermatofibroma and dermatofibrosarcoma protuberans

In selected cases, the clinicopathological distinction between deep penetrating dermatofibroma (DPDF), which involves the subcutis, and dermatofibrosarcoma protuberans (DFSPs) may be challenging. In most instances, attention to the cytological constituency of the lesions and the overall architecture is sufficient to make this separation. DPDF is typified by cellular heterogeneity, including giant cells and lipidized histiocytes; when it extends into the hypodermis, it does so either using the interlobular subcuticular fibrous septa as scaffolds or in the form of broad pushing fronts of tumor. In contrast, DFSP is a cytologically monotypical tumor, which entraps subcutaneous adipocytes diffusely or grows in stratified horizontal plates in the hypodermis. In the minority of cases where conventional morphological analysis of optimal biopsy specimens is diagnostically indeterminate, immunostaining for CD34 and factor XIIIa (FXIIIa) is helpful; it is also often necessary when a poorly-representative sample of the lesion has been obtained by the clinician. Characteristically, DF is diffusely FXIIIa-reactive and CD34-negative, whereas DFSP manifests the converse of those findings. Other markers such as Ki-M1p, mutant p53 protein, and metallothionein may also provide adjuvant diagnostic information in this context, as may the observation of abnormalities in chromosomes 17 and 22 by direct karyotypic analysis.

Histogenetic relations between giant cell fibroblastoma and dermatofibrosarcoma protuberans. CD34 staining showing the spectrum and a simulator

The authors describe three lesions that provide further evidence for a close, possibly histogenetic relation between giant cell fibroblastoma and dermatofibrosarcoma protuberans. The first case involves a dermatofibrosarcoma protuberans that contained a single giant cell fibroblastoma-like focus of multi-nucleate giant cells. A second tumor, a giant cell fibroblastoma, recurred 6 years later as a dermatofibrosarcoma protuberans. In the third lesion, there was a juxtaposition and co-mingling of dermatofibrosarcoma protuberans and giant cell fibroblastoma within the same primary lesion. In all cases, both the giant cell fibroblastoma areas and dermatofibrosarcoma protuberans areas stained positively with CD34. A fourth case, a dermatofibrosarcoma protuberans infiltrated skeletal muscle, creating giant cell fibroblastoma-like giant cell mimics--a result of skeletal muscle degeneration or atrophy with nuclear conglomeration. The latter giant cells failed to express CD34 but did show immunoreactivity with desmin. These findings support the concept that giant cell fibroblastoma and dermatofibrosarcoma protuberans probably represent a histologic spectrum of a single CD34 positive (perhaps, dermal dendrocytic) neoplasm, a conclusion supported by a recently cloned t(7;22) breakpoint demonstrated in both neoplasms.

Ten years of the cytogenetics of soft tissue tumors

Recent cytogenetic and molecular genetic investigations in solid tumors in general, and in soft tissue tumors in particular, have provided us with a wealth of information. We have gained new insights in how tumors may arise, and some soft tissue tumors besides their identification by pathology now also have a genetic identity. This genetic identity is defined by: specific chromosome changes and by molecular changes related to the chromosome anomalies. However, much work remains to be done. In soft tissues as in other solid tumors many tumor types await the first or more extensive chromosome investigation, and in those in which nonrandom, especially simple chromosome changes emerge, molecular studies are to be undertaken starting from the breakpoints. Those tumors that seem to deviate chromosomally or molecularly from the expected, because of already established genetic changes, must be more thoroughly investigated by both pathologists and geneticists. The same accounts for the molecular investigation of chromosomally normal tumors known to show subtypes with specific chromosomal changes: e.g. lipoma, leiomyoma.

Cellular fibrous histiocytoma of the skin: evidence of a clonal process with different karyotype from dermatofibrosarcoma

Recently, a distinct variant of cutaneous fibrous histiocytoma (FH) has been histologically characterized as a "cellular" subtype. This variant is often mistaken for sarcoma, including dermatofibrosarcoma protuberans. We report a case of cellular FH of the skin in which the cytogenetic analysis demonstrated a novel chromosome pattern, possibly allowing distinction from its histologic simulants.

Another case of t(17;22)(q22;q13) in an infantile dermatofibrosarcoma protuberans

We have identified a new dermatofibrosarcoma protuberans (DP) case with a t(17;22) (q22;q13) occurring in a child. The translocation was substantiated by the presence of one or two copies of the sole der(22)t(17;22). This rearrangement added to two normal chromosomes 17 and one or two chromosomes 22, resulted in trisomy 22cen-q13 and trisomy (or tetrasomy) 17q22-25. This observation confirms the specificity of the association of DP with the t(17;22) found together with extra copies of the der(22)t(17;22). It also points out a possible prevalence of translocation rather than rings in DP of the childhood disease.