Tenascin differentiates dermatofibroma from dermatofibrosarcoma protuberans: comparison with CD34 and factor XIIIa

Bednar's tumor at right shoulder in an adult male: a case report of a rare entity

Introduction and importance

Bednar tumor, a rare variant of dermatofibrosarcoma protuberans is a tumor with low malignant potential. Owing to limited studies, the pathogenesis and risk factor of this tumor are not clearly understood. The tumor extends from the epidermis to the dermal layers and even affects the surrounding bone. Here, the authors present a case of a 48-year-old male with a Bednar tumor, which was successfully managed by wide local excision and flap repair.

Case presentation

Our patient presented to the hospital after the reappearance of mass, 6 years after the excision of the previously misdiagnosed lipoma. Vitals and systematic examination were normal. Local examination revealed an oval-shaped mass with a glistening surface on the right shoulder. The patient underwent wide excision and skin flap surgery for the treatment, and the diagnosis was confirmed through histopathological examination and immunohistochemistry for the CD34 marker.

Clinical discussion

Bednar tumor is an infrequent skin tumor linked to genetic anomalies and is one of the rare variants [(<0.1%) of skin tumors]. Diagnosis can be done by histopathological examination and CD34 marker positivity via immunohistochemistry. This tumor is mistaken for lipoma, leading to recurrent growth postexcision. The tumor demands a broader resection due to the high chances of reoccurrence. Although Mohs micrographic surgery is the ideal approach, its limited availability in resource-constrained settings prompts alternative strategies.

Conclusion

This case highlights the challenges of diagnosis, the rarity of the condition, and the need for vigilant follow-up due to the tumor's propensity for recurrence.

Dermatofibroma Versus Dermatofibrosarcoma Protuberans: A Nuclear Morphology Study

ABSTRACT

The locally invasive soft-tissue sarcoma, dermatofibrosarcoma protuberans (DFSPs), shares certain histologic features of the much more common and benign dermatofibroma (DF). While immunohistochemical stains, specifically cluster of differentiation 34 and Factor XIIIa, can be used to distinguish the 2 entities using microscopy, these markers are not entirely sensitive nor specific. Three-dimensionally, DFSP nuclei resemble a "puck" or "coin"-like shape. As hematoxylin/eosin-stained slides are prepared, these "puck" nuclei are fixed in an infinite number of orientations depending on their current position in rotation about their axes within the tumor cells. Under histological examination, this random nuclear positioning produces the appearance of 2 predominate morphologies: an ovoid "disk" shape (en face) and a narrow spindled shape (side view), which distribute in a roughly 50:50 ratio throughout the tumor sample slide. Nuclear morphology was analyzed in 324 DFSP and DF samples at high magnification (×400) to determine the presence or absence of a predominant morphology in which nuclei appear to alternate between an ovoid (en face) and spindled (side view) throughout most of the tumor sample. An alternating ovoid-spindled nuclear morphology was the predominant cytology in 98% of DFSP and was not predominant in 100% of DF samples (P < 0.001). This morphology was found to be highly specific (Sp = 1) and sensitive (Sn = 0.98) for DFSP. This unique nuclear morphology may be a more sensitive and specific diagnostic tool in identifying DFSP from DF in comparison with costly immunohistochemical stains.

Dermatofibromas with Aberrant Expression of CD34 Protein: A Systematic Review and a Reappraisal of Clinicopathological Features and Histogenesis

BACKGROUND

Dermatofibromas (DFs) are benign fibrohistiocytic lesions that usually do not express CD34 protein. This study aimed to analyze the literature concerning the immunohistological and ultrastructural features of DFs. It also related these features to the histogenesis of these lesions.

METHODS

This study included a PubMed literature search for studies addressing the clinicopathological, ultrastructural, and immunohistochemical features of DFs. It also presented some current cases of CD34-negative DFs and a subset of these lesions with aberrant expression of this protein.

RESULTS

Analysis of the PubMed literature revealed that DFs with an aberrant expression of CD34 are rare tumors that commonly affect the extremities of adult females. Separating these tumors from dermatofibrosarcoma protuberans (DFSP, CD34-positive tumors) requires using a large panel of immunostains. Ultrastructurally, DFs are composed of diverse cell types, including cells with histiocytic, myofibroblastic, and fibroblastic features. An analysis of the DFs described by this study revealed that cases with an aberrant expression of CD34 protein had slightly high mean age and male sex predominance when compared to CD34-negative cases. The former commonly affected the extremities. There was no evidence of local recurrence or distant metastasis on follow-up.

CONCLUSIONS

DFs have the potential to express CD34 protein, defining a rare aberrant phenotype, which was not associated with any differences in the outcome as compared to CD34-negative DFs.

Current Update on the Molecular Biology of Cutaneous Sarcoma: Dermatofibrosarcoma Protuberans

OPINION STATEMENT

Cutaneous sarcoma is a group of malignant mesenchymal tumors primarily involving the dermis, and it is characterized by extreme clinicopathological heterogeneity. Although its occurrence rate is rare, dermatofibrosarcoma protuberans (DFSP) is one of the most common types of dermal sarcoma. DFSP grows slowly and tends to relapse locally after inadequate resection. There are various histological variants of DFSP tumors and it often mimics benign lesions such as dermatofibroma and scar, which make accurate diagnosis difficult and delayed, and some cases progress to the stage where the tumor is unresectable. Recent advancements in cancer genetics and molecular biology methods have elucidated the COL1A1-PDGFB fusion gene, some novel fusion gene variants and pathways related to DFSP pathogenesis that have resulted in the evolution of cutaneous sarcoma diagnosis and treatment. For example, some clinical studies have confirmed the efficacy of imatinib methylate, an αPDGFR-targeted therapy for unresectable or metastatic DFSP. The present review summarizes recent updates in DFSP research, diagnostics, and treatment.

Phosphohistone-H3 and Ki67: Useful Markers in Differentiating Dermatofibroma From Dermatofibrosarcoma Protuberans and Atypical Fibrohistiocytic Lesions

Dermatofibromas (DF) are common, benign, skin tumors, usually easily differentiated from dermatofibrosarcoma protuberans (DFSP) by the presence of a relative low cellularity, lesser degree of infiltration of subcutaneous tissue, and immunohistochemical pattern (eg, FXIIIa in DF and CD34 in DFSP). Atypical fibrohistiocytic lesions (AFL) have features intermediate to DF and DFSP (trunk location, storiform pattern, infiltration of the subcutaneous tissue, and focal expression of both CD34 and Factor XIIIa). It is unclear if mitotic counts/degree of proliferation is helpful to distinguish DF from DFSP. To study the mitotic rate and proliferation index in DF, AFL/DFSP, anti-ki67, and anti-PHH3 were performed on 10 cases of DF (including 4 cellular DF), 10 standard DFSP, and 2 AFL. The proliferation index and mitotic figures were counted per square millimeter in a "hotspot" (in a fashion similar to mitotic counts in melanoma). All cases of DF showed much higher Ki67 proliferation index (P = 0.0001) along with increased mitotic figures both on H&E and with anti-PHH3 (P = 0.0001) when compared to AFL/DFSP. Our data indicate that DF has a higher proliferation index and mitotic counts when compared to superficial/peripheral portion of AFL and DFSP. This finding may be helpful in the differential diagnosis among these fibrohistiocytic lesions.

Multiple, Clustered Dermatofibroma: A Rare Clinical Variant of Dermatofibroma

Background:

Although patients with one to two dermatofibromas are common, cases of “multiple” dermatofibromas (more than 15 lesions) are rare and may occur in the context of altered or normal immune function. Patients with multiple dermatofibromas clustered in one anatomic area, by contrast, are strikingly rare.

Objective:

The aim of our study was to present an additional case of multiple, clustered dermatofibroma (MCDF) and to summarize the literature concerning this entity.

Methods:

We performed a MEDLINE (1960–2001) database search using keywords “dermatofibroma” AND “clustered” OR “agminated” OR “grouped.”

Results:

Five case reports were identified using this search strategy. These cases demonstrated substantial similarity in clinical features and behavior, specifically, the presence of pruritic symptoms, no clear inciting incident, an early active growth phase followed by stabilization, predilection for the lower extremity, and no report of sarcomatous transformation.

Conclusion:

Despite an active early growth phase, MCDF appears to follow a benign clinical course, with no report of sarcomatous transformation at up to 20 years followup.

Immunohistochemistry in dermatopathology

CONTEXT

Immunohistochemistry is not a diagnostic test but a highly valuable tool that requires interpretation within a context.

OBJECTIVE

To review the current status and limitations of immunohistochemistry in dermatopathology.

DATA SOURCES

English-language literature published between 1980 and 2014.

CONCLUSIONS

Although immunohistochemistry is rarely completely specific or sensitive, it is an important adjunctive technique in dermatopathology and can be helpful in a series of diagnostic dilemmas.

Identification of leukocyte-specific protein 1-positive cells: a clue to the cell of origin and a marker for the diagnosis of dermatofibroma

Background

Dermatofibroma (DF) comprises a heterogeneous group of mesenchymal tumors, with fibroblastic and histiocytic elements present in varying proportions. The cell of origin of DF has been investigated, but remains unclear.

Objective

The present study attempted to investigate the expression of leukocyte-specific protein 1 (LSP1), a marker of fibrocytes, in DF. Additionally, we evaluated the effectiveness of LSP1 in the differential diagnosis of DF from dermatofibrosarcoma protuberans (DFSP).

Methods

Immunohistochemical staining was performed on 20 cases of DF using antibodies against LSP1, CD68, and factor XIIIa (FXIIIa). In addition, the expression of LSP1 and FXIIIa was evaluated in 20 cases of DFSP.

Results

Eighteen of 20 cases (90%) of DF stained positive for LSP1, with variation in the intensity of expression. CD68 was positive in 10 cases (50%), and FXIIIa was expressed in all cases of DF. There were differences between the regional expression patterns of the three markers in individual tumors. In contrast, only 2 of 20 cases of DFSP expressed LSP1, and none of DFSP cases stained positive for FXIIIa.

Conclusion

The LSP1-positive cells in DF could potentially be fibrocyte-like cells. FXIIIa and CD68 expression suggests that dermal dendritic cells and histiocytes are constituent cells of DF. It is known that fibrocytes, dermal dendritic cells and histiocytes are all derived from CD14+ monocytes. Therefore, we suggest that DF may originate from CD14+ monocytes. Additionally, the LSP1 immunohistochemical stain could be useful in distinguishing between DF and DFSP.

A Case of Cellular Fibrous Histiocytoma on the Right Elbow with Repeated Relapse within a Short Period

Cellular fibrous histiocytoma, a variant of fibrous histiocytoma, is a designation used for lesions showing increased cellularity with a fascicular growth pattern and frequent extension into the subcutis. Here we describe a case of cellular fibrous histiocytoma showing repeated recurrence in a 36-year-old woman who initially presented with a 2-cm cutaneous tumor on her right elbow. Histopathologically, the first resected specimen demonstrated irregularly arranged collagen fibers mixed with scattered proliferating plump to spindle-shaped fibrohistiocytes. However, examination of the resected specimens obtained after recurrence showed that the cellularity had increased, the spindle-shaped cells showing monomorphic proliferation with a fascicular and storiform growth pattern extending into the subcutis, as well as an increase of Ki-67 positivity. Since the lesion showed repeated relapse within a short period, we performed wide-field resection of the tumor with a 3-cm margin. Currently, 48 months after surgery, there has been no local recurrence or metastasis, but continuous strict follow-up will be necessary.

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.

Follicular induction overlying a dermatofibrosarcoma protuberans

The term "induction" has been used to describe epidermal changes overlying a dermatofibroma (DF). Follicular induction is most often associated with DF, but can be observed in other lesions, including focal mucinosis, nevus sebaceous, seborrheic keratosis, wart, neurofibroma, and scars. Dermatofibrosarcoma protuberans (DFSP) is a malignant fibrohistiocytic tumor that may be difficult to distinguish from DF. In contrast to DF, the epidermis overlying DFSP is usually attenuated or ulcerated. Here, we report a case of DFSP exhibiting follicular induction of the overlying epidermis. This epidermal change has been rarely reported in DFSP and may present a diagnostic pitfall in superficially sampled lesions.

Genetic aberrations in imatinib-resistant dermatofibrosarcoma protuberans revealed by whole genome sequencing

Dermatofibrosarcoma protuberans (DFSP) is a very rare soft tissue sarcoma. DFSP often reveals a specific chromosome translocation, t(17;22)(q22;q13), which results in the fusion of collagen 1 alpha 1 (COL1A1) gene and platelet-derived growth factor-B (PDGFB) gene. The COL1A1-PDGFB fusion protein activates the PDGFB receptor and resultant constitutive activation of PDGFR receptor is essential in the pathogenesis of DFSP. Thus, blocking PDGFR receptor activation with imatinib has shown promising activity in the treatment of advanced and metastatic DFSP. Despite the success with targeted agents in cancers, acquired drug resistance eventually occurs. Here, we tried to identify potential drug resistance mechanisms against imatinib in a 46-year old female with DFSP who initially responded well to imatinib but suffered rapid disease progression. We performed whole-genome sequencing of both pre-treatment and post-treatment tumor tissue to identify the mutational events associated with imatinib resistance. No significant copy number alterations, insertion, and deletions were identified during imatinib treatment. Of note, we identified newly emerged 8 non-synonymous somatic mutations of the genes (ACAP2, CARD10, KIAA0556, PAAQR7, PPP1R39, SAFB2, STARD9, and ZFYVE9) in the imatinib-resistant tumor tissue. This study revealed diverse possible candidate mechanisms by which imatinib resistance to PDGFRB inhibition may arise in DFSP, and highlights the usefulness of whole-genome sequencing in identifying drug resistance mechanisms and in pursuing genome-directed, personalized anti-cancer therapy.

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.

IGFBP7, a novel immunohistochemical marker in differentiating dermatofibroma from dermatofibrosarcoma protuberans

BACKGROUND

Loss of insulin-like growth factor-binding protein 7 (IGFBP7) has been found to be a critical step in the development of melanoma and colon cancer. To our knowledge, immunostaining of IGFBP7 in various dermatofibrosarcoma protuberans (DFSP) and dermatofibroma (DF) has not been studied before.

OBJECTIVES

To assess the immunostaining of IGFBP7 in DFSPs and DFs and to ascertain whether IGFBP7 is superior to antibodies traditionally used in differentiating DFs from DFSPs.

METHODS

Immunohistochemical staining was performed on 28 cases of DFSP and 30 cases of DF, using antibodies to IGFBP7, CD34, factor XIIIa (FXIIIa), CD10 and stromelysin-3 (ST-3).

RESULTS

Six of 28 (21.4%) DFSP samples were positive for IGFBP7, whereas 28 of 30 (93.3%) DF samples were positive. CD34 was positive in 26 of 28 (92.9%) cases of DFSP and 4 of 30 (13.3%) cases of DF. FXIIIa staining was positive in 4 of 28 (14.3%) cases of DFSP and 28 of 30 (93.3%) cases of DF. CD10 staining was positive in 12 of 28 (42.9%) cases of DFSP and ST-3 staining was positive in 7 of 28 (25.0%) cases of DFSP. The preferential IGFP7 staining of DFSPs in comparison with DFs was statistically significant (P < 0.01).

CONCLUSIONS

We confirmed that IGFBP7 is a negative immunohistochemical marker for DFSPs and the combination with CD34, FXIIIa and ST-3 immunostaining could make the distinction more reliable.

Late local recurrence of dermatofibrosarcoma protuberans in the skin of female breast

Dermatofibrosarcoma protuberans (DFSP) of the breast is exceptionally obscure and late local recurrence of this entity on this site is even more uncommon. We describe such a case in a 48-year-old woman, who at the age of 35 had a DFSP excised from her right breast. Thirteen years later, she developed an ovoid mass in her right breast over the postsurgical scar area. Wide local excision of the tumor with generous tissue margin was performed and microscopic and immunohistochemical findings established the diagnosis of recurrent DFSP. No further treatment was administered and she remains well 18 months later, without tumor recurrence. We report an exceptionally rare case of local recurrence of DFSP in the female breast and discuss in detail the diagnostic and therapeutic implications of this pathology.

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.

Pedunculated hemangiopericytoma-like tumor: peculiar fibroepithelial polyp or fibrous histiocytoma variant

Pathologists are continually challenged with the difficult task of discriminating between innocuous disease processes and potentially malignant entities. Apropos of this concern, we present a series of three cutaneous polypoid lesions that simulated fibroepithelial polyp, yet upon close scrutiny yielded histologic features of solitary fibrous tumor (SFT) or hemangiopericytoma. These pedunculated lesions showed a storiform pattern of spindled cells with interspersed gaping vascular channels reminiscent of SFT or hemangiopericytoma. Interestingly, the immunohistochemical staining profile of these lesions was negative for CD34 and positive for bcl-2 and factor XIIIa. These findings were discordant with SFT and suggest a relationship with fibrous histiocytoma. We propose that this entity represents a hitherto described variant of fibrous histiocytoma known as pedunculated hemangiopericytoma-like fibrous histiocytoma.

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.

Tenascin expression in actinic keratosis

BACKGROUND

Tenascin is an extracellular matrix protein frequently expressed around neoplastic and non-neoplastic lesions of the skin. Actinic keratoses (AKs) are intraepidermal neoplastic lesions of the sun-exposed skin. They are classified according to the extension of dysplasia in four stages; they also present different histological varieties.

METHODS

We performed an immunohistochemical study using tenascin monoclonal antibody diluted 1 : 50 on 150 cases of AKs classified, respectively, in histotypes (38 hypertrophic, 18 atrophic, 21 bowenoid, 19 acantolytic, and 40 mixed) and in stages (27 stage I, 46 stage II, 42 stage III, and 35 stage IV; 14 in tumoral progression).

RESULTS

Tenascin positivity was observed in all cases at the dermal level close to the epithelial lesion. The intensity of reaction increased from stage I to stage IV and, of course, also in tumoral progression. Its expression was not related to the histotypes. In very few cases, the atypical keratinocytes were positive.

CONCLUSIONS

Tenascin expression in AKs is related to the stages of dysplasia. In fact, the immunostaining intensity corresponds to the degree of the dysplasia rather than the thickness of the involved epidermis. Tenascin plays a role in neoplastic progression working as an anti-adhesive factor.

Smallpox vaccination site complications

The typical resolution of the smallpox vaccination site is a smooth scar, a sequela that is discussed during prevaccination counseling. In addition, other types of lesion may develop at the scar site, including short- or long-term benign and malignant changes, as reviewed below. Although current recommendations do not discuss potential scar complications or scar surveillance, healthcare providers would benefit from an awareness of these potential complications, and should consider periodic scar surveillance as part of a general physical examination.

Expression of CD163 in dermatofibroma, cellular fibrous histiocytoma, and dermatofibrosarcoma protuberans: comparison with CD68, CD34, and Factor XIIIa

BACKGROUND

Distinction between cellular fibrous histiocytomas (FHs) with a deep component and dermatofibrosarcoma protuberans (DFSPs) can pose diagnostic problems. While CD68, CD34, and Factor XIIIa are helpful in distinguishing between these entities, none are diagnostically absolute. Recent work with CD163, a hemoglobin scavenger receptor, has demonstrated that this marker has high specificity for monocytes, macrophages, and histiocytes. Our goal is to evaluate the utility of CD163 in the diagnosis of dermatofibromas (DFs), cellular FHs, and DFSPs.

METHODS

Sixty cases including 19 DFs, 23 cellular FHs with a deep component, and 18 DFSPs were tested with antibodies against CD163, CD68, CD34, and Factor XIIIa.

RESULTS

CD163 was expressed in 17/19 (89%) DFs, 23/23 (100%) cellular FHs, and 3/18 (17%) DFSPs. CD68 was positive in 8/19 (42%) DFs, 19/23 (83%) cellular FHs, and 1/16 (6%) DFSPs. CD34 was expressed in 1/19 (5%) DFs, 5/23 (22%) cellular FHs, and 100% of DFSPs. Factor XIIIa labeled 4/19 (21%) DFs, 11/23 (48%) cellular FHs, and 0/17 cases of DFSPs.

CONCLUSIONS

CD163 expression is helpful in distinguishing between cellular FHs and DFSPs and will be useful in a panel of antibodies when these entities are in the differential diagnosis. Sachdev R, Sundram U. Expression of CD163 in dermatofibroma, cellular fibrous histiocytoma, and dermatofibrosarcoma protuberans: comparison with CD68, CD34, and Factor XIIIa.

Dermatofibrosarcoma protuberans at the site of a central venous line. Case report

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive cutaneous tumor that usually does not metastasize. Clinically, it may present as a reddish macule to protuberant nodule affecting the trunk and proximal extremities of young and middle-aged adults. Histologically, it is characterized by a monomorphous storiform proliferation of spindle cells, involving the dermis and hypodermis, with a honeycomb pattern of infiltration of the subcutaneous fat. In case of difficulty in diagnosis, immunohistochemical markers (especially CD34) are highly sensitive for DFSP. It is important to remember that the rarity of DFSP, its resemblance to hypertrophied scars and keloids, and its appearance at trauma sites sometimes make the diagnosis of DFSP difficult and delayed. In the literature, DSFP was not described in a child until 1957. Here we report an instance of DFSP at an unusual site in a 9-year-old child, which was the location of a previous central venous line insertion in the left supraclavicular area. A complete excision of the tumor with a wide surgical margin of 3cm of visibly uninvolved tissue was performed, followed by a deltopectoral flap and skin split graft. Postoperatively, the patient's general condition was stable and he was discharged after 5 days to be followed up 3 months later in our clinic.

Tenascin C and cathepsin d expression in adipocytic tumors: an immunohistochemical investigation of 43 cases

Cathepsin D (CatD) and tenascin C (Tn-C) have been implicated in invasion and metastasis of carcinomas. However, little is known about CatD and Tn-C distribution in mesenchymal tumors. Therefore, we aimed to investigate the expression of Tn-C and CatD in adipocytic tumors. Tn-C and CatD expressions in 27 lipomas, 5 atypical lipomatous tumor/well-differentiated liposarcomas (ALT/WDLS) and 11 liposarcomas (LS) were evaluated by immunohistochemistry and scored semiquantitatively. CatD expression was higher in ALT/WDLS than in lipomas (p<0.001), and higher in LS than in ALT/WDLS (p=0.009). Stromal Tn-C expression was higher in ALT/WDLS than in lipomas (p=0.02), but no difference was observed between ALT/WDLS and LS (p>0.05). These results indicate that Tn-C and CatD may be markers of locally aggressive or malignant behavior in adipocytic tumors.

Differential Expression of HMGA1 and HMGA2 in Dermatofibroma and Dermatofibrosarcoma Protuberans: Potential Diagnostic Applications, and Comparison with Histologic Findings, CD34, and Factor XIIIa Immunoreactivity

The histologic distinction of dermatofibrosarcoma protuberans (DFSP) and dermatofibroma (DF) may be difficult, especially in the case of DF extending into the subcutaneous fat (deep DF). CD34 and Factor XIIIa staining is commonly used in separating DF from DFSP, but is not always helpful. HMGA1 and HMGA2 genes, members of the high mobility group protein family genes, encode proteins that act as architectural transcription factors and are frequently dysregulated in a variety of benign or locally aggressive mesenchymal tumors. In this study, we evaluated the immunoreactivity of HMGA1 and HMGA2 in a series of DF and DFSP to determine the possible utility for these markers in the differential diagnosis of these two entities. Immunohistochemical stains were performed on paraffin-embedded tissues from 22 cases of DF, including 14 cases of deep DF and 14 cases of DFSP, using antibodies against HMGA1 and HMGA2. CD34 and Factor XIIIa immunoreactivity was also evaluated in these lesions and compared with the results of HMGA immunostaining. Immunopositivity for both HMGA1 and HMGA2 was seen in 21of 22 (96%) DFs, but in only 3 (21%) and 1 (7%) of 14 DFSPs, respectively. While 100% of DFSP stained for CD34, 36% of DF also labeled for CD34. The immunoreactivity of HMGA1 and HMGA2 in DF was generally strong and diffuse, in contrast to weak and focal staining seen in DFSP. The proportion of cases with positive immunoreactivity for both markers was significantly higher in DF and in deep DF than in DFSP (P < 0.001). We conclude that HMGA1 and HMGA2 expression can be used to distinguish DF from DFSP with a degree of accuracy that is fully equivalent to that of Factor XIIIa and CD34.

Low recurrence rate after surgery for dermatofibrosarcoma protuberans: a multidisciplinary approach from a single institution

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare sarcoma with a propensity for local recurrence. Treatments with wide excision, Mohs surgery, and other approaches have been reported with widely variable local control rates. The objective of this study was to review the experience with a multidisciplinary approach employing wide excision and Mohs surgery selectively in the treatment of patients with DFSP at a single academic institution over the past 10 years.

METHODS

The records of 62 patients with 63 DFSP tumors who underwent wide excision, Mohs surgery, or a multidisciplinary combination approach from January 1991 to December 2000 were reviewed retrospectively. Primary endpoints included the ability to extirpate the DFSP lesion completely, the tumor recurrence rate, and the need for skin grafts or local tissue flaps. Additional objectives included defining surgical practice patterns at the authors' institution.

RESULTS

Sixty-three DFSP lesions were removed from 62 patients. At a median follow-up of 4.4 years, no local or distant recurrences were detected in any patient. Forty-three lesions were treated with wide local excision, 11 lesions were treated with Mohs surgery, and 9 lesions were treated with a combination approach. Ninety-five percent of lesions that were approached initially with wide local excision were cleared histologically. Two patients (5%) received postoperative radiation for positive margins after undergoing maximal excision. Eighty-five percent of lesions that were approached initially with Mohs surgery were cleared histologically. The remaining 15% of lesions subsequently were cleared surgically with a wide excision. DFSP lesions that were approached initially with Mohs surgery tended to be smaller. Patients with head and neck lesions most often underwent Mohs surgery or were treated with a multidisciplinary combination approach (87%).

CONCLUSIONS

Wide local excision with careful pathologic analysis of margins was found to have a very low recurrence rate and was used for the majority of patients with DFSP lesions at the authors' institution. Wide local excision, Mohs surgery, and a multidisciplinary combination approach, selected based on both tumor and patient factors, were capable of achieving very high local control rates in the treatment of DFSP. The evolution of a multidisciplinary approach has provided a level of expertise that no single individual could achieve for the treatment of the full spectrum of DFSP lesions at the authors' institution.

Multiple Eruptive Dermatofibromas with CD34+ Cells in a Patient with Hypertriglyceridemia

Multiple eruptive dermatofibromas (MEDF) are rare and have been thought to be associated with altered immunity. It has been reported that dermatofibromas (DFs) are positive for factor X IIIa but not for CD34. In this report, we describe a 34-year-old Japanese woman with MEDF and persistent hypertriglyceridemia. Histopathological examination revealed that several areas in larger nodules, showing higher cellularity and storiform growth pattern, had CD34+ cells. Our case and the review of previous reports suggest that hyperlipidemia, including hypertriglyceridemia, could induce MEDF and that highly cellular areas in DFs are sometimes positive for CD34.