Giant Cell Fibroblastoma: A Case Report and lmmunohistochemical Comparison with Ten Cases of Dermatofibrosarcoma Protuberans

A 7 year old boy with giant cell fibroblastoma (GCF) of the skin and subcutaneous tissue of the right chest wall is described. To date, the histogenesis of GCF has not been clarified. The reason for the diversity of immunohistochemical data among various authors may be because the specimens studied were from only part of the lesion, or reduction of antigenicity through the preparation process. However, our findings based on studies of many specimens from various parts of the tumor for accurate immunohistochemical evaluation suggest that GCF may be a myofibro histiocytic tumor. Recently, the suggestion that GCF is a juvenile form of dermatofibrosarcoma protuberans (DFSP) has been reported. In addition to the present case, we performed immunohistochemical examination of 10cases of definitely diagnosed DFSP for comparison. The immunohistochemical characteristics of these two neoplasms were concordant. However, from clinical and morphological viewpoints, it seems premature to recognize GCF as a juvenile form of DFSP. Acta Pathol Jpn 41: 552–560, 1991.     

Giant cell fibroblastoma: a report of three cases with histologic and immunohistochemical evidence of a relationship to dermatofibrosarcoma protuberans

PROBLEM CONSIDERED: Giant cell fibroblastoma (GCF) is a rare mesenchymal neoplasm, which is classified as a fibrohistiocytic tumor of intermediate malignancy owing to its propensity for local recurrence, although metastasis has not been documented. Prior reports have linked GCF to dermatofibrosarcoma protuberans (DFSP), given overlapping clinical and histologic features. METHODS: This report documents three additional cases of GCF that further support the contention that this lesion is histogenetically related to DFSP. RESULTS: All three lesions occurred on the trunk of patients whose ages were 4, 28, and 38 years. One case that histologically resembled a GCF on initial excision recurred with areas of both GCF and DFSP. A second recurrence was composed entirely of DFSP. Another case contained areas of both GCF and DFSP, as well as a focus that was felt to be undergoing fibrosarcomatous change. The third case consisted entirely of GCF. Immunohistochemically, all three lesions showed intense immunoreactivity for CD34 in the GCF component. CD34 also strongly marked the cells in those cases with a DFSP component. CONCLUSIONS: Although GCF may not represent the "juvenile form" of DFSP, as previously suggested, the evidence strongly supports a histogenetic relationship between these two lesions, even though the cell of origin remains obscure.     

Genomic gains of COL1A1-PDFGB occur in the histologic evolution of giant cell fibroblastoma into dermatofibrosarcoma protuberans

Giant cell fibroblastoma (GCF) is a subcutaneous mesenchymal neoplasm characterized by the chromosomal t(17;22), which results in the formation of the fusion gene COL1A1-PDGFB. This same fusion gene is also seen in the supernumerary ring chromosome of dermatofibrosarcoma protuberans (DFSP). Several studies have addressed the molecular genetics of DFSP but molecular cytogenetic characterization of individual areas and cell components in pure GCF and GCF/DFSP hybrids have not been performed. Herein, we studied the frequency and genomic copy number of COL1A1-PDGFB in pure GCF and GCF/DFSP hybrids, and identified the molecular cytogenetic signatures in individual cells in each component. Four pure GCF and nine GCF/DFSP hybrids were studied. All tumors exhibited classical histological features and CD34 expression. COL1A1 and PDGFB rearrangements were evaluated by fluorescence in situ hybridization (FISH) using probes for COL1A1 and PDGFB on paraffin-embedded thin tissue sections. All GCF and GCF/DFSP hybrids showed unbalanced rearrangements of COL1A1-PDGFB at the molecular cytogenetic level. Genomic gains of COL1A1-PDGFB were found predominantly in the DFSP component of GCF/DFSP hybrids but in none of the pure GCF, suggesting that these gains are associated with the histologic evolution of GCF into DFSP. The molecular cytogenetic abnormalities were found not only in the spindle/stellated cells but also in individual nuclei of the multinucleated giant cells, suggesting that these cells may result from the fusion of individual neoplastic cells.     

Composite tumor consisting of dermatofibrosarcoma protuberans and giant cell fibroblastoma associated with intratumoral endometriosis. Report of a case

We present a unique case of composite skin tumor of the vulva consisting of dermatofibrosarcoma protuberans (DFSP) and giant cell fibroblastoma (GCF) with an intratumoral focus of endometriosis. A 31-year-old female with a 10-year-history of a recurring subcutaneous tumor in the vulvar area underwent excision of the seventh recurrence of the tumor. Microscopic examination revealed a composite fibrohistiocytic tumor consisting of DFSP and GCF. Additionally, a focus of endometriosis within the tumor tissue was found. Malignant transformation of extragonadal endometriosis has already been described; we present, however, the occurrence of a focus of endometriosis within the tissue of a hormonally independent soft tissue tumor. There is a possible link to the occurrence of cutaneous endometriosis at previous surgery sites and in the scars. The presence of endometriosis within the soft tissue tumor represents, to the best of our knowledge, a previously undescribed collision phenomenon.     

巨细胞纤维母细胞瘤的临床与病理学观察

目的：研究巨细胞纤维母细胞瘤的临床病理学特点和免疫组织化学表型,探讨其鉴别诊断及组织学起源。方法：采用光镜观察结合免疫组织化学LSAB法标记对7例巨细胞纤维母细胞瘤进行分析。结果：7例患者中6例为儿童,1例为35岁成年人。男性5例,女性2例。临床上主要表现为躯干和四肢皮下缓慢增大的无痛性结节,平均直径2．9cm。镜下显示,肿瘤境界不清,主要位于真皮层。瘤细胞主要由轻至中度异型的梭形细胞组成,多呈疏松的束状或波浪状排列,间质呈纤维黏液样,部分区域呈致密胶原化。本病的特征性形态表现肿瘤内含有一些不规则分布的裂隙样或扩张窦样的假脉管性腔隙,其腔隙面内衬一层不连续的梭形细胞和核深染多核巨细胞,两种细胞在形态上有移行。免疫组织化学标记显示梭形细胞和多核巨细胞均表达波形蛋白和CD34.5 附有随访资料,其中2例术后复发。结论：（1）巨细胞纤维母细胞瘤是一种好发于儿童的中间性纤维母细胞性肿瘤,较易局部复发,掌握其独特的临床病理学特征对避免误诊为一些具有相似形态的病变具有重要意义;（2）巨细胞纤维母细胞瘤与好发于成人的隆突性皮纤维肉瘤的在临床表现、免疫组织化学、细胞及分子遗传学上均极为相似,在组织上也可共存,提示两者在组织学发生了关系密切,可能同属CD34阳性树突状纤维母细胞肿瘤一族。     

Composite Tumor Consisting of Dermatofibrosarcoma Protuberans and Giant Cell Fibroblastoma Associated with Intratumoral Endometriosis

We present a unique case of composite skin tumor of the vulva consisting of dermatofibrosarcoma protuberans (DFSP) and giant cell fibroblastoma (GCF) with an intratumoral focus of endometriosis.A 31-year-old female with a 10-year-history of a recurring subcutaneous tumor in the vulvar area underwent excision of the seventh recurrence of the tumor. Microscopic examination revealed a composite fibrohistiocytic tumor consisting of DFSP and GCF. Additionally, a focus of endometriosis within the tumor tissue was found.Malignant transformation of extragonadal endometriosis has already been described; we present, however, the occurrence of a focus of endometriosis within the tissue of a hormonally independent soft tissue tumor. There is a possible link to the occurrence of cutaneous endometriosis at previous surgery sites and in the scars. The presence of endometriosis within the soft tissue tumor represents, to the best of our knowledge, a previously undescribed collision phenomenon.     

FNA diagnosis of giant cell fibroblastoma: A case report of an unusual pediatric soft tissue tumor

Giant cell fibroblastoma (GCF) is a rare pediatric soft tissue tumor, which exists on a spectrum with dermatofibrosarcoma protuberans (DFSP). Histologic features are well established for these entities; however, cytologic findings have not been well characterized. We report for the first time a case of GCF, confirmed by cytogenetics, with mixed DFSP features. In this case of an 8‐month‐old boy, a fine needle aspiration specimen showed a low‐grade spindle cell tumor, with oval to spindled cells dispersed singly and in patternless groups, and with occasional giant cells. Subsequent histologic features were consistent with GCF, which is an uncommon, CD34 positive, soft tissue neoplasm with a distinct molecular aberration. This case emphasizes the differential diagnosis in pediatric soft tissue tumors and stresses the unique features of GCF. Diagn. Cytopathol. 2015;43:325–328. © 2014 Wiley Periodicals, Inc.     

Composite dermatofibrosarcoma protuberans-giant cell fibroblastoma recurring as Bednár tumor-giant cell fibroblastoma with mucoid lakes and with amputation neuroma

We report an unusual case of composite giant cell fibroblastoma-dermatofibrosarcoma protuberans (DFSP) that, in its second recurrence, contained a pattern of Bednár tumor (BT) and giant cell fibroblastoma (GCF). The recurrent tumor showed extreme myxoid change with creation of mucoid lakes, which mimicked a pattern of myxoid liposarcoma. One area in the recurrent lesion contained amputation neuroma overgrown with neoplastic spindle cells, which simulated a nerve sheath neoplasm. This case demonstrates common histogenesis of GCF, DFSP and BT, and it shows how broad morphological spectrum can be produced by a composite tumor, especially when the tumor includes unconventional growth pattern or additional non-neoplastic lesion.     

隆突性皮肤纤维肉瘤72例临床病理学观察

目的 观察隆突性皮肤纤维肉瘤(DFSP)的临床病理特点，探讨诊断、鉴别诊断及其组织起源。方法 对72例DFSP病例进行临床表现、组织形态学、免疫组化研究，16例真皮纤维瘤(DF)、19例神经纤维瘤(NF)、17例纤维肉瘤(FS)分别作为对照。结果 72例DFSP好发中青年男性，肿瘤为单发或多发性结节，位于真皮，可浸润皮下脂肪及横纹肌。组织形态除经典的车辐状或席纹状结构外，还存在一些变异如黏液变性、伴FS区域、Bednar瘤等。DFSP组87％CD34阳性，NF组42％CD34阳性。结论 掌握DFSP的临床病理特点，避免与其它皮肤梭形细胞肿瘤尤其是DF、NF及黏液性肿瘤混淆。CD34阳性提示DFSP可能与神经鞘膜有关。     

Dermatofibrosarcoma protuberans with EMa+ cells. Report of a case suggesting perineurial cell differentiation

A case of dermatofibrosarcoma protuberans (DFSP) with epithelial membrane antigen (EMA)-positive cells is described. The tumor was excised from the left groin of a 28-year-old woman. It showed characteristic histologic features of DFSP with typical diffuse immunohistochemical positivity for CD34. Moreover, scattered neoplastic cells expressed EMA, suggesting perineural cell differentiation. Ultrastructural study found perineurial cell features, such as thin long bipolar cytoplasmic processes, pinocytotic vesicles, fragments of external lamina and/or external lamina-like material, attachment plaques, and desmosome-like junctions. This observation, together with previous immunohistochemical findings of EMA-positive cells in a subset of DFSPs, strongly suggests perineurial cell differentiation in these tumors. DFSP should be included in the differential diagnosis of EMA-positive spindle cell lesions of superficial soft tissue and skin.     

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.     

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.     

Complex t(5;8) involving the CSPG2 and PTK2B genes in a case of dermatofibrosarcoma protuberans without the COL1A1-PDGFB fusion

Dermatofibrosarcoma protuberans (DFSP) is a rare, dermal neoplasm of intermediate malignancy. It is made of spindle-shaped tumor cells in a storiform pattern positive for CD34. Cytogenetically, DFSP cells are characterized by either supernumerary ring chromosomes composed of sequences derived from chromosomes 17 and 22 or more rarely of translocations t(17;22). These chromosomal rearrangements lead to the formation of a specific chimeric gene fusing COL1A1 to PDGFB. So far, the COL1A1-PDGFB fusion gene remains the sole fusion gene identified in DFSP. However, some observations suggest that genes, other than COL1A1 and PDGFB, might be involved in some DFSP cases. We report in this paper a DFSP case presenting as a unique chromosomal abnormality a complex translocation between chromosomes 5 and 8. This is the first report of a DFSP case where the lack of chromosomes 17 and 22 rearrangement and the absence of COL1A1-PDGFB fusion gene have been demonstrated. Using fluorescence in situ hybridization analysis, we showed that the CSPG2 gene at 5q14.3 and the PTK2B gene at 8p21.2 were disrupted by this rearrangement. Although rare, the existence of cases of DFSP negative for the COL1A1-PDGFB fusion has to be taken in consideration when performing molecular diagnosis for a tumor suspected to be a DFSP.     

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.     

Immunohistochemical Analysis of CXCR4 Expression in Fibrohistiocytic Tumors

Functional chemokine receptors are expressed in many malignant tumors. These receptors promote tumor growth and metastasis in response to endogenous chemokines. We analyzed the expression of CXCR4, CCR6 and CCR7 in fibrohistiocytic tumors, including dermatofibrosarcoma protuberance (DFSP), malignant fibrous histiocytoma (MFH), dermatofibroma (DF) using immunohistochemistry. We also investigated the relationship between CXCR4 and CD34, the latter of which is an immunohistochemical marker for DFSP. We observed a higher expression of CXCR4 in DFSP and MFH as compared with DF. Interestingly, a significantly higher expression of CXCR4 was detected in relapsed DFSP than in non-relapsed DFSP, but no significant differences were detected between non-relapsed DFSP and DFSP with CD34 immunostaining. Moreover, MFH had strong immunoreactivity for CXCR4, CCR6 and CCR7. These findings suggest that the assessment of CXCR4 immunoreactivity in fibrohistiocytic tumors is a useful tool for predicting tumor aggressiveness.     

石蜡包埋隆突性皮肤纤维肉瘤组织中COL1A1/PDGFB融合基因的表达

目的检测隆突性皮肤纤维肉瘤(DFSP)中COL1A1／PDGFB融合基因的表达并探讨其临床病理学意义。方法应用一步法逆转录一聚合酶链反应(RT-PCR)检测12例4％甲醛固定、石蜡包埋DFSP组织中t(17;22)(q22;q13．1)染色体易位融合基因COL1A1／PDGFB mRNA表达,并选用2例纤维肉瘤、2例恶性纤维组织细胞瘤、3例平滑肌肉瘤、1例神经鞘瘤、1例纤维组织细胞瘤作为对照。结果12例DFSP中8例(67％)检出COL1A1／PDGFB mRNA的表达,其中PDGFB分别与COL1A1不同的位点相融合,而对照组均为阴性。结论用一步法RT-PCR检测石蜡包埋DFSF组织中特异性的COL1A1／PDGFB mRNA的表达,有助于DFSP的诊断和阐明其分子发生机制。     

Microsatellite instability and p53 mutation associated with tumor progression in dermatofibrosarcoma protuberans

Dermatofibrosarcoma protuberans (DFSP) is a dermal and subcutaneous tumor categorized as a tumor of intermediate malignancy, and its progression in some cases to fibrosarcoma is well known. However, molecular analysis of tumor progression has been limited. The present study investigated microsatellite instability (MSI) of 7 microsatellite markers through high-resolution microsatellite analysis in addition to a mutational analysis of the p53 gene in 44 tumors in 36 patients. The patients were divided into 2 groups: 9 patients with a fibrosarcomatous component in the primary or recurrent/metastasized tumor, designated as the DFSP+FS group, and the remaining 27 patients, designated as the DFSP group. Cases in which the percentage of markers with an additional peak among the markers successfully analyzed was more than 30% was considered MSI high (MSI-H); cases in which microsatellites were stable at all of the successfully examined markers were considered microsatellite stable (MSS); and the remaining cases were considered MSI low (MSI-L). MSI-H cases were observed more frequently in the DFSP+FS group (4 of 9 cases) than in the DFSP group (1 of 27 cases) (P = 0.028, Fischer's exact test). The MSI status of recurrent or metastatic tumors in both the DFSP+FS and the DFSP groups was the same as that in the corresponding primary neoplasms. Furthermore, there was no difference in MSI status between an ordinary DFSP area and a fibrosarcomatous area in 7 tumors that exhibited both areas. p53 mutational analysis revealed 10 point mutations, composed of 4 missense mutations and 6 silent mutations, in 6 of 36 cases (16.7%). A missense mutation was more frequently observed in the DFSP+FS group (3 of 4) than in the DFSP group (1 of 4). Among 3 cases of a missense mutation in the DFSP+FS group, 2 had a mutation only in a fibrosarcomatous area and 1 had a mutation only in a metastatic tumor progressing to fibrosarcoma. These results suggest that MSI and p53 mutations are involved in tumor progression of DFSP to fibrosarcoma as early and late events, respectively.