Collagen Features of Dermatofibrosarcoma Protuberans Skin Base on Multiphoton Microscopy.

Dermatofibrosarcoma protuberans is a rare, low-grade skin fibroblastic tumor which tends to recur locally due to its high misdiagnosis. Dermatofibrosarcoma protuberans usually spreads through the intracutaneous and subcutaneous layers into the deep dermis layer in which the main component is collagen. Therefore, alterations in collagen shape and content are important for accurate diagnosis of dermatofibrosarcoma protuberans. In this study, multiphoton microscopy was employed to observe normal human skin and dermatofibrosarcoma protuberans skin. Then, a centerline based on an algorithm that skeletonizes a binary image of fibers was applied to analyze collagen shapes in 2 types of skin. Then, collagen content, including intensity and density, was quantitatively obtained to demonstrate differences between the 2 skin types. Results indicate that collagen shape and density can be considered as auxiliary diagnostic parameters to improve the accuracy of dermatofibrosarcoma protuberans diagnosis.

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.

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).

Bednar tumor: report of a case with immunohistochemical and ultrastructural study.

A slowly growing tumor in the right shoulder of a 38-year-old white male, which felt like a superficial cystic mass, was studied. The spindle cells, which represented the main component of the tumor, were arranged in a typical storiform pattern and were positive for CD34 and focally for CD117. The pigmented cells were mostly found at the center of the storiform whorls and were negative for S-100 protein and HMB-45. Ultrastructurally, the tumor consisted predominantly of nondescript mesenchymal spindle cells that resembled fibroblasts. The tumor cells blended into a loosely arranged stromal tissue background. The general appearance of pigmented cells was very similar to the nonpigmented spindle cells. The pigment appeared to be a mature form of melanin granules. The lack of premelanosomes, cell injections, basal lamina, and pinocytotic vesicles was inconsistent with a neural origin/neural differentiation hypothesis for this tumor.

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.

An ultrastructural and immunohistochemical study of pigmented dermatofibrosarcoma protuberans (Bednar tumor).

A case of Bednar tumor on the right shoulder of a 47-year-old Japanese woman is reported. Histological examination showed plump, spindle cells arranged in a storiform pattern in central areas of the tumor and a diffuse infiltration of the dermal stroma, which was frequently extended into the subcutis at the periphery of the tumor. The tumor contained a fairly identified population of dendritic pigmented cells. Ultrastructurally, most cells had folded nuclei, were spindle-shaped and had long, slender cytoplasmic projections. Dendritic pigmented cells, which were dispersed among neoplastic cells, contained premelanosomes and mature melanosomes. Immunohistochemically, tumor cells exhibited positive reactions for vimentin and CD 34 and failed to show a positive reaction for neuron specific enolase, HMB-45 or S-100 protein. Factor X IIIa was only expressed on tumor cells around melanin-containing cells, which reacted positively with antibodies to S-100 protein and vimentin. These results indicate that the phenotype of tumor cells around melanin-containing cells differs from other tumor cells and that this difference may be caused by the relationship of tumor cells and melanin-containing cells.

Estudio de la expresion del antigeno de células progenitoras CVD34 (HPCA-1) en dermatofibrosarcoma protuberans: sus implicancias / Expression of the human progenitor cell antigen CD34 (HPCA-1) studied in dermatofiobrosarcoma protuberans: its implications

Presentamos cuatro casos de dermatofibrosarcoma protuberans (DFSP). Se estudió la expresión del antígeno de células progenitoras humanas (HPCA-1) CD34 en estos tumores. Aplicando el anticuerpo monoclonal murino anti-HPCA-1 (anti-CD34) a los cortes de poarafina de rutina pudimos demostrar reactividad CD34 marcada en todos los casos de DFSP. Como muchos otros autores, concluímos que la inmunotinción CD34 es un marcador confiable para DFSP y podría facilitar la distinción entre estos tumores de otros tumores fibrohistiocíticos, especialmente del fibrohistiocitoma

Myxoid dermatofibrosarcoma protuberans: morphological, ultrastructural and immunohistochemical features.

Two uncommon cases of dermatofibrosarcoma protuberans with prominent myxoid changes are presented. The tumors appeared as large multinodular cutaneous plaques that arose at the sites of excision of previous tumors some years earlier. In addition to limited fibrous storiform features, focally observed in deep and peripheral portions of the tumors, a diffuse myxoid pattern could be observed. The latter consisted of homogeneous areas of rare, stellate or spindle-shaped cells, haphazardly scattered in abundant myxoid matrix. Cells of myxoid neoplastic tissue showed mainly a positive immunoreaction for fibrohistocytic markers and the absence either of muscular, neural or human progenitor cell antigens. Mitotic figures were fewer and cell proliferation rates were lower in myxoid as compared to those of typical dermatofibrosarcoma protuberans used as a control. The ultrastructural examination of myxoid areas revealed a prevalent fibroblast-like cell population showing dilated cytoplasmic vesicles, sometimes containing glycosaminoglycans-like substances. The extent of myxoid changes together with the characteristic morphological, ultrastructural and immunohistochemical features confirm that myxoid dermatofibrosarcoma protuberans is a distinct variant of this fibrohistiocytic tumor to be considered in the differential diagnosis among myxoid tumors of the skin.

Dermatofibrosarcoma protuberans and its fibrosarcomatous variant with areas of myoid differentiation: a report of three cases.

AIMS: We describe three examples of dermatofibrosarcoma protuberans which demonstrated focal myofibroblastic differentiation, and discuss the nature of myofibroblastic differentiation. METHODS AND RESULTS: We studied three cases of dermatofibrosarcoma protuberans, two of which had fibrosarcomatous portions containing myoid areas, and one which showed myoid areas in ordinary dermatofibrosarcoma protuberans. Myoid areas were recognized histologically as randomly distributed, scattered bundles or small nodules of spindle cells with deeply eosinophilic cytoplasm. Myofibroblastic differentiation was demonstrated immunohistochemically by positive staining for smooth muscle actin and muscle-specific actin, and ultrastructurally by the presence of microfilament bundles with focal dense bodies and pinocytic vesicles. The myoid areas occasionally contained intraneoplastic blood vessels. CONCLUSION: The presence of myoid areas may be related to reactive hyperplasia of stroma, and its relation to the histogenesis of dermatofibrosarcoma protuberans is uncertain.

Phenotype and proliferation characteristics of cultured spindle-shaped cells obtained from normal human skin and lesions of dermatofibroma, Kaposi's sarcoma, and dermatofibrosarcoma protuberans: a comparison with fibroblast and endothelial cells of the dermis.

Normal human dermis contains mesenchymal cells that are generally referred to as fibroblasts. However the relationships between fibroblasts and endothelial cells with respect to the types of spindle-shaped cells that are present in cultures obtained from tumor bearing-skin is unclear. To explore the potential heterogeneity amongst dermal-derived cells that grow in culture with a spindle-shaped morphology, we compared the immunophenotype and growth characteristics of several types of cells. Besides dermal fibroblasts and microvascular endothelial cells derived from normal adult skin, we also studied large vessel-derived endothelial cells, and spindle-shaped cells derived from three different tumor-bearing dermal-based neoplasms. Kaposi's sarcoma (KS), dermatofibroma (DF), and dermatofibrosarcoma protuberans (DFSP). A broad panel of eight different antibodies were used to immunophenotype the multi-passaged cultured cells. Spindle-shaped cells from all three neoplasms could be distinguished from the normal skin derived fibroblasts by their constitutive expression of factor XIIIa, and the gamma-interferon induced expression of VCAM-1. All seven types of cultured cells stained positive for s-actin and proline-4-hydroxylase, and none of the cells expressed CD34. Both large and small-vessel derived endothelial cells expressed factor VIII, ELAM-1, and VCAM-1. Using two different types of growth media, significant differences were also observed amongst these cultured cell types. Spindle-shaped cells from DFSP did not grow in DMEM containing 10% fetal bovine serum (DMEM-FBS); but they proliferated in KS cell growth medium (KSGM). Spindle-shaped cells from DF grew best in KSGM, but not in DMEM-FBS. KS tumor cells grew well in KSGM, but not in DMEM-FBS. Fibroblasts proliferated in DMEM-FBS, but failed to grow in KSGM; and even when pre-treated with conditioned medium from a transformed KS cell line (i.e. SLK cells), no fibroblast proliferation could be induced in KSGM. These results indicate that KS cell line (i.e. SLK cells), no fibroblast proliferation could be induced in KSGM. These results indicate that even though dermal-derived cells can have an identical spindle-shape by light microscopy, significant heterogeneity can be defined amongst such cells from normal and tumor-bearing human skin. Having established culture conditions to propagate these different cell types and phenotypic criteria to distinguish them from one another, will provide new research opportunities to explore the function and ontogeny of the diverse mesenchymal cells that take on a spindle-shaped morphology in culture.

Fibrosarcomatous dermatofibrosarcoma protuberans with myofibroblastic differentiaion: a histologically distinctive variant [corrected].

We report two examples of dermatofibrosarcoma protuberans with fibrosarcomatous change, in which the fibrosarcomatous component of the tumor demonstrated focal myofibroblastic differentiation. This was recognized by light microscopy as plump myoid cells associated with abundant extracellular collagen production, immunohistochemically by positive staining for smooth muscle and muscle specific actin, and ultrastructurally by subplasmalemmal filament aggregates and micropinocytotic vesicles. Myofibroblastic differentiation has not been described before in dermatofibrosarcoma protuberans with fibrosarcomatous change and because of a lack of information concerning the immunohistochemical profile of this variant of DFSP its incidence is unknown. Focal myofibroblastic differentiation, as demonstrated in the fibrosarcomatous regions of these two tumors, might support the proposed dermal fibroblastic origin for dermatofibrosarcoma protuberans with fibrosarcomatous change.

Dermatofibrosarcoma protuberans: ultrastructural and immunocytochemical observations.

In an attempt to elucidate the histogenesis of dermatofibrosarcoma protuberans, 38 specimens were examined by electron microscopy and immunocytochemistry. The cumulative evidence strongly favors a fibroblastic/myofibroblastic derivation.

Ultrastructure of composite tumours consisting of giant cell fibroblastoma and dermatofibrosarcoma protuberans.

We present here ultrastructural findings in three composite tumours having giant cell fibroblastoma--dermatofibrosarcoma protuberans components occurring in adult patients. We further hypothesize that these 3 tumours belong to the group of neoplasms that can show giant cell fibroblastoma, dermatofibrosarcoma protuberans, dendritic pigment cell, myxoid, and fibrosarcomatous differentiation. We consider the giant cell fibroblastoma areas of the tumours to represent a well-differentiated component of these neoplasms.

Nuclear morphometry of soft tissue tumors of fibrous origin.

In this study we investigated the diagnostic significance of a set of different morphometric nuclear parameters in the differential diagnosis of soft tissue tumors. Nuclear area, the standard deviation of the nuclear area, the shape factor and other parameters such as Feret's Diameter and Martin's Radii were assessed using a computer assisted image analyzer system. A statistically significant difference (p < 0.01) between benign and malignant tumors and tumor-like lesions could be confirmed for the nuclear area and the standard deviation of the nuclear area, with the significance level being lower (p = 0.5) for the latter parameter. The shape factor also discriminated between the examined groups. Reclassification of the assessed histological diagnosis was performed by linear discriminant analysis using all possible combinations of the different nuclear parameters. This procedure disclosed an increasing rate of correctly reclassified cases with rising number of parameters applied. We conclude that the assessment of nuclear parameters may be helpful in the correct diagnosis and differential diagnosis of soft tissue tumors and tumor-like lesions of fibrous origin.

[Ultrastructural study of 14 cases of dermatofibrosarcoma protuberans].

14 cases of dermatofibrosarcoma protuberans (DFSP) were investigated with electron microscopy. Perineural cells, fibroblasts and primitive mesenchymal cells were found in all cases with perineural cells as the most prominent component. The findings suggest that DFSP is a tumor with heterogeneity, most probably arising from primitive dermal mesenchymal cells which have the potential for differentiation toward different cell lines, especially toward perineural cells.