Non-polarizable collagen in dermatofibrosarcoma protuberans: a useful diagnostic aid

Polarized Microscopy in Lesions With Altered Dermal Collagen

Alterations in dermal collagen are noted in dermatofibroma, dermatofibrosarcoma protuberans, morphea, lichen sclerosus et atrophicus, hypertrophic scars, and keloids. The authors sought to determine whether variations in birefringence of collagen by polarized microscopy could be of help in diagnosing such conditions. Representative hematoxylin and eosin sections of 400 cases, including dermatofibroma, dermatofibrosarcoma protuberans, hypertrophic scars, keloid, morphea, and lichen sclerosus, were examined under polarized microscopy. Distinct patterns of birefringence of collagen for each disease were noted under polarized microscopy. This study highlights the use of polarized microscopy as adjunctive tool in differentiating different diseases with collagen alteration.

Utilization of polarized microscopy to differentiate deep penetrating nevus from equine type melanomas

Equine type melanoma can mimic deep penetrating nevus (DPN), making histologic diagnosis challenging. We sought to investigate if the pattern of collagen polarization could be helpful in this setting. A total of 52 specimens were reviewed with polarized microscopy to determine whether refractile collagen was present within melanocytic nests vs. surrounding but not within the nests. Seven of eight (87.5%) equine type melanomas demonstrated refractile collagen within melanocytic nests in part or all of the lesion. In contrast, DPN showed no refractile collagen within the melanocytic nests. Instead, 12 (100%) DPNs and 14 of 16 (87.5%) common combined nevi (DPN plus banal nevus) demonstrated refractile collagen only surrounding melanocytic nests. The entrapment of refractile collagen, as seen with polarized microscopy, within melanocytic nests can support a diagnosis of equine type melanoma.

Immunohistochemical expression of matrix metalloproteinases 1, 2, 9, and 14 in dermatofibrosarcoma protuberans and common fibrous histiocytoma (dermatofibroma)

CONTEXT

Common fibrous histiocytoma (cFH) or dermatofibroma and dermatofibrosarcoma protuberans (DFSP) are 2 spindle cell mesenchymal tumors that are distinguished in part by their microscopic growth patterns and clinically by the greater propensity for DFSP to recur. Matrix metalloproteinases (MMPs) potentially play a role in modulating the growth patterns of cFH and DFSP by remodeling the extracellular matrix.

OBJECTIVE

To evaluate the immunohistochemical (IHC) expression of MMP-1, MMP-2, MMP-9, and MMP-14 in DFSP and cFH, because (1) MMP-1, MMP-2, MMP-9, and MMP-14 are synthesized by dermal fibroblasts, the major constituent of DFSP and cFH; and (2) platelet-derived growth factor B, which is overexpressed in most examples of DFSP because of t(17;22), activates ets-1, a transcription factor that regulates molecules associated with tumor invasion and metastasis, including MMP-1, MMP-3, and MMP-9.

DESIGN

Immunohistochemical studies were performed on archived, formalin-fixed, paraffin-embedded tissue of DFSP (n = 48) and cFH (n = 47).Results.-Significant IHC expression (>10% of tumor cells) in cFH included MMP-14 (27 [59%] of 46 tumors positive), MMP-2 (21 [47%] of 45 tumors positive), MMP-9 (9 [20%] of 45 tumors positive), and MMP-1 (6 [13%] of 46 tumors positive). No DFSPs showed significant IHC expression of any of the MMPs evaluated. However, anti- MMP-2 highlighted a rich microvascular element within deep tumor tissue present in 81% of DFSPs with a prominent subcutaneous component.

CONCLUSION

Our IHC results indicate that MMP-1 and MMP-9 are not up-regulated in DFSP. Convincing expression of MMP-14 in cFH suggests that this MMP may affect the growth pattern of the lesion, perhaps by activating MMP-2 expression in tumor cells. In DFSP, MMP-2 may play a role in tumor angiogenesis.

CD44 and hyaluronate in the differential diagnosis of dermatofibroma and dermatofibrosarcoma protuberans

The histological distinction between dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP) may be extremely difficult. CD34 and Factor XIIIa have been used to differentiate DF from DFSP. However, there is an overlap and relative lack of specificity of their expressions. CD44 is a widely distributed integral membrane glycoprotein, which is expressed as a multitude of isoforms generated by alternative splicing of at least 10 different variant exons and post-translational modifications. CD44 is currently thought to be the principal cell surface receptor for hyaluronate (HA), the major component of the extracellular matrix. In this study we aimed to assess the expression of standard CD44 (CD44s) and its isoforms (CD44v3, CD44v4, CD44v5, CD44v6, CD44v7, CD44v7v8, and CD44v10), and HA in DF and DFSP. Immunohistochemical staining was performed on the biopsy specimens of 15 cases of DF and four cases of DFSP, using antibodies that recognize the CD44s, different CD44 isoforms and the hyaluronate binding protein (HABP). Tumor cells displayed a strong CD44s immunoreactivity in all cases of DF whereas a faint HA positivity was observed in the tumor stroma. The DF cells were negative for CD44v3, CD44v4, CD44v6, CD44v7 and CD44v7v8 but showed a strong reactivity for CD44v5 and CD44v10. In contrast, CD44s' expression was significantly reduced or absent in all DFSP lesions and the tumor stroma displayed strong staining for HA. Our results indicate that CD44 and HA can be used as additional diagnostic markers to distinguish DF from DFSP.

Indeterminate fibrohistiocytic lesions of the skin: is there a spectrum between dermatofibroma and dermatofibrosarcoma protuberans?

Routine histology and immunohistochemistry can usually distinguish dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP). DF generally expresses factor XIIIa whereas DFSP generally expresses CD34. The authors report 10 cutaneous fibrohistiocytic lesions combining clinical, histologic, and immunohistochemical features of both DF and DFSP. The lesions had an average size of 1.2 cm (range, 0.4-2.7 cm), and occurred on the trunk (n = 6), extremities (n = 3), and face (n = 1) of four men and six women (average age, 30.6 yrs; age range, 15-50 yrs). Eight lesions exhibited acanthosis and densely cellular fascicles with focal storiform areas. All had keloidal collagen, infiltrated the subcutis in a honeycomb pattern, and had low mitotic counts (0 to 4 mitoses per square millimeter). All were diffusely immunoreactive for factor XIIIa (30%-60% of the neoplastic cells) as well as CD34 (20%-70%). This series raises the possibility of a biologic spectrum between DF and DFSP; however, double-immunolabeling studies showed no notable coexpression of factor XIIIa and CD34 by individual cells, suggesting coexistence of two different cellular populations. After an average follow up of 22.3 months (range, 10-46 mos) in six cases, a single recurrence was documented. The ambiguous histologic features and the potential for local recurrence suggest that performing a complete excision may be prudent in these diagnostically indeterminate lesions.

Histopathologic and immunohistochemical diagnosis of benign and malignant fibrous and fibrohistiocytic tumors of the skin

This article describes the histopathology and immunohistochemistry of benign and malignant fibrous and fibrohistiocytic tumors. Some of the benign fibrohistiocytic proliferation's have atypical variants which could be misinterpreted as malignant processes. Key points for the diagnosis of these entities based on routine histology and immunohistochemistry are presented.

Pretreatment with intralesional hyaluronidase prior to excision of dermatofibrosarcoma protuberans

Dermatofibrosarcoma protuberans (DFSPs) are an uncommon malignancy that commonly recur, but rarely metastasize. The origin of DFSPs is controversial; however, they stain with the progenitor marker CD34. DFSPs usually show increased stromal mucin, mainly hyaluronic acid (HA). HA increases cellular proliferation, delays differentiation and increases cellular motion. We evaluated the pretreatment of DFSPs with intralesional injections of hyaluronidase (HD) prior to the surgical excision. Five of nine cases of DFSPs were pretreated with HD. In HD-pretreated cases the margins for excision of the residual tumor were reduced. HD pretreatment also decreased CD34 staining and increased polarizable collagen in the residual tumor.

Immunohistochemical characterization of dermatofibrosarcoma protuberans with practical applications for diagnosis and treatment

Dermatofibrosarcoma protuberans (DFSP) is a rare, clinically challenging, soft tissue tumor. The main histologic differential of DFSP is usually a dermatofibroma. In 1990, the first report appeared demonstrating that cells of DFSP express the human progenitor antigen CD34 on their surface. Since then, there have been increasing reports of the usefulness of immunohistochemical staining with CD34 to differentiate DFSP from dermatofibroma and other soft tissue tumors. This literature is reviewed with special emphasis on the insights studies have provided into the histogenesis of DFSP. The literature demonstrating the practical applications of CD34 staining in the diagnosis and treatment of DFSP is also discussed.

Dermatofibrosarcoma protuberans

Dermatofibrosarcoma protuberans is a tumor of intermediate malignancy characterized by its aggressive local growth and marked propensity to recur after surgical excision. This article reviews the incidence, clinical presentation, histologic features, immunocytochemical studies, histogenesis, prognosis, management, and follow-up recommendations for this unusual neoplasm.

Dermatofibrosarcoma protuberans is a unique fibrohistiocytic tumour expressing CD34

Dermatofibrosarcoma protuberans (DFSP) is a slow growing, locally invasive tumour whose differentiation from other fibrohistiocytic tumours sometimes poses serious diagnostic problems. We investigated CD34 expression immunohistologically in various fibrohistiocytic tumours including dermatofibroma, DFSP, malignant fibrous histiocytoma (MFH), infantile myofibromatosis, fibrosarcoma, hypertrophic scar and keloid. Among these, DFSP was unique in that tumour cells themselves expressed CD34, whereas in other tumours. CD34 expression was observed only on vascular endothelial cells amongst the tumour cells. Until now, there have been no reports of useful immunohistological markers for DFSP. CD34 expression by the tumour cells can be an extremely useful marker in establishing a definitive diagnosis of DFSP.

What's new in dermatopathology

This article reviews the recent English language literature on dematopathology, with an emphasis on publications appearing between January 1986 and July 1987. Immunohistochemistry continues to grow in importance as a diagnostic as well as a research technique. The advent of in situ deoxyribonucleic acid hybridization technology has raised diagnostic accuracy to a new level; it has already proved valuable in the diagnosis of certain viral infections. Areas that have received particular attention include phenotypic characteristics of lymphomas and lymphoma-like conditions, congenital melanocytic nevi and malignant melanoma, neuroendocrine carcinoma and other small cell tumors of the skin, sweat gland carcinomas, and eosinophil and its associated diseases, and unusual infectious diseases involving the skin.