Granular cell variant of dermatofibrosarcoma protuberans

Dermatofibrosarcoma protuberance with a unique appearance mimicking neurofibroma arising from a conventional area

A 21 year-old Japanese man had a rapidly growing pedunculated soft tumor in the abdomen within the past year, the base of which had persisted for 17 years. A skin biopsy of the soft part resembled neurofibroma. However, the excised specimen showed that the tumor base comprised spindle cells arranged in a storiform fashion and expanded around fat cells with a honeycomb infiltration. All areas of the tumor were positive for CD34 and negative for S-100. Finally, the tumor was diagnosed as a myxoid dermatofibrosarcoma protuberance arising from a conventional area. The pedunculated shape on the conventional part was unique. Myxoid dermatofibrosarcoma protuberances may pose a diagnostic challenge, particularly with a small biopsy. Thus, we should carefully consider dermatofibrosarcoma protuberances or other malignant mesenchymal tumors as a differential diagnosis in cases of low cellularity and abundant stromal tumors resembling neurofibromas.

A case report of abdominal metastatic dermatofibrosarcoma protuberans misdiagnosed as gastrointestinal stromal tumor

Dermatofibrosarcoma protuberans (DFSP) is a low-grade malignant soft-tissue tumor that originates from the skin. It has a slow onset in the early stages, non-specific clinical symptoms, low specificity, and can easily be overlooked, missed, or misdiagnosed by clinicians and pathologists. In addition, DFSP is prone to recurrence after local surgical treatment; however, distant metastasis, especially abdominal metastasis, is rare, which is also a challenge for the accurate diagnosis of DFSP when it progresses distantly. Now a case of abdominal metastasis of DFSP is reported. The patient has been treated with imatinib for ten years, and the lesion has shrunk, but because the patient has been receiving imatinib treatment, his abdominal lesion was once misdiagnosed as gastrointestinal stromal tumor. Therefore, we report on this case to enhance the understanding of the diagnosis and treatment of DFSP, and to provide reference for the pathological diagnosis and precise treatment of such patients.

Rare Variants of Dermatofibrosarcoma Protuberans: Clinical, Histologic, and Molecular Features and Diagnostic Pitfalls

Dermatofibrosarcoma protuberans (DFSP) is a dermal malignant mesenchymal tumor. Most variants are associated with a high risk of local recurrence and a low risk of metastasis. The classic histomorphology of this tumor is made up of uniform, spindle-shaped cells, arranged in a storiform pattern. Tumor cells characteristically infiltrate the underlying subcutis in a honeycomb pattern. Less common variants of DFSP have been identified: myxoid, pigmented, myoid, granular cell, sclerosing, atrophic, and fibrosarcomatous. Only the fibrosarcomatous variant has been shown to differ significantly from classic DFSP in terms of clinical outcome; fibrosarcomatous DFSP has been shown to be associated with a greater risk of local recurrence and metastatic potential than classic DFSP. However, the other variants may pose diagnostic difficulty as they resemble other types of spindle cell neoplasms, especially in small biopsy specimens. This article reviews the clinical, histologic, and molecular features of DFSP variants, as well as possible pitfalls in their diagnosis and how to resolve them.

Granular cell dermatofibroma: A potential diagnostic pitfall

Dermatofibroma, also known as “fibrous histiocytoma”, is one of the most common cutaneous soft-tissue tumours. Many variants of dermatofibromas have been described and knowledge of these variations is important to avoid a misdiagnosis of a possibly more aggressive tumour. Histological features of different variants can coexist in the same lesion, but typical common fibrous histiocytoma features are generally found, at least focally, in all cases. However, when cellular changes make up the majority of the lesion, the histopathological diagnosis can become more complex and requires immunohistochemical investigations for a correct nosographic classification. We report on the case of a cutaneous fibrous histiocytoma, “granular cell” variant, found on the left leg of a 74- year-old woman.

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.

Guidelines for Diagnosis and Treatment of Cutaneous Sarcomas: Dermatofibrosarcoma Protuberans

Sarcomas comprise a broad group of tumors, many of whose biological behavior and aggressiveness differ from one type to another. The therapeutic approach is generally multidisciplinary and often complex. Developments in surgical and oncological dermatology during the last few decades have positioned dermatologists as specialists in the diagnosis and treatment of skin cancer. The aim of this article is to review the main soft tissue sarcomas that typically affect the skin. Dermatofibrosarcoma protuberans is a low-grade malignant sarcoma. It exhibits slow-growth, is locally invasive, and has low metastatic potential (<3%). Mohs micrographic surgery is the treatment of choice. The COL1A1-PDGFB translocation should be analyzed in cases of unclear diagnosis and when it is necessary to identify candidates for tyrosine kinase inhibitors. Imatinib is indicated for the treatment of locally advanced and metastatic dermatofibrosarcoma protuberans.

Benign Granular Cell Tumor of the Breast: A Misleading Disease

Granular cell tumor (GCT) is a relatively rare neoplasm, and almost always benign in its prognostic behavior. Location of this tumor in the breast presents serious problems for differential diagnosis, both from a clinical point of view and at gross pathological examination, because of its resemblance to carcinoma. Fine needle aspiration biopsy and intraoperative frozen section examination may not be of any further help. The histogenesis of these lesions has been widely debated in the past, but no universally accepted conclusion has been reached. Most GCTs appear to be derived from Schwann cells, but many different neoplastic and non-neoplastic lesions show granular cell changes. Therefore, GCT should not be considered as a single entity but as the result of a cytoplasmic change due to still unknown metabolic alterations that may occur in various cell types. No firm conclusions can be drawn regarding the suspected hormonal influence on the development of breast GCT.

The authors describe three typical cases of breast GCT that occurred in patients of different ages, and discuss the most important questions concerning this lesion.

Leiomyosarcoma of the great saphenous vein (vena saphena magna) with granular cell change: Report of a superficial neoplasm

The great saphenous vein (GSV) corresponds to the main superficial large-caliber vessel affected by leiomyosarcoma (LMS). Given its superficial location and because signs of vascular origin may not be clinically apparent, LMS of the GSV may be misinterpreted clinically as superficial nonvascular soft tissue mass. Herein, we report a case on the distal portion of the right GSV of a 57-year-old man. The histopathological recognition of a large-caliber vein-associated LMS (with granular cell change) in an incisional biopsy specimen was crucial to guide radiological evaluation and confirmation of a superficial vascular LMS before surgical treatment. Recognizing this entity in small biopsies is important as its surgical treatment and prognosis differ substantially from nonvascular superficial (ie, subcutaneous and dermal) LMSs. In addition, because vascular LMSs can involve long vessel segments, underestimation of extent of disease is a risk. To the best of our knowledge, granular cell change has not been documented in LMS of the GSV.

Bilateral multifocal upper extremity atypical granular cell tumors presenting as long-standing right wrist and left hand masses in a 15-year-old African-American female

Granular cell tumor (GrCT) is a benign nerve sheath tumor. Atypical and malignant variants of GrCT are rare but have been well described. We report a case of multifocal symmetric atypical GrCT in the bilateral hand/wrists of a 15-year-old African-American female. The initial clinical impression for both masses was favored to be ganglion cysts. Ultrasound findings of both masses revealed hypoechoic soft tissue lesions with some internal echogenicity favoring complex cysts. On excision, both masses were histologically circumscribed, lobulated and attached to tendon. Large epithelioid cells with abundant granular eosinophilic cytoplasm arranged in syncytial cords and trabeculae percolated through collagen. Many cells had pleomorphism and/or prominent nucleoli. Mitotic figures, spindling, high nuclear-to-cytoplasmic ratio and necrosis were absent. Both masses showed diffuse S100 protein but negative desmin and pancytokeratin expression. Ki-67 index was 1% to 2%. p53 was positive in 5% to 10% of nuclei. Both masses met criteria for atypical (but not malignant) GrCT. Our case shows that atypical GrCT may be not only multifocal but also symmetric. We speculate that migration of defective neural crest stem cells along both upper limb buds during embryogenesis may have allowed these essentially identical tumors to arise in similar locations bilaterally simultaneously.

Gastric Epithelioid Stromal Tumor (Leiomyoma) With Granular Changes

A unique case of gastric epithelioid stromal tumor (leiomyoma) demonstrating granular changes is reported. Microscopically, the tumor was composed of polygonal or fusiform cells with a coarse, granular eosinophilic cytoplasm, focally admixed with fascicles of spindle-shaped cells. A marked lymphoid infiltrate forming follicles was also a characteristic finding. Immunohistochemically, these cells were positive for alpha-smooth-muscle actin, HHF-35 (muscle-specific actin), and NKI/C3 but negative for desmin, S100 protein, vimentin, lysozyme, and Mac-387. This case demonstrates that granular cell changes and prominent lymphoid aggregates are not limited to gastric stromal tumors with neural differentiation.

Palisading and Verocay body-prominent dermatofibrosarcoma protuberans: A case report

Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous sarcoma with a tendency for local recurrence, which commonly presents as a slowly growing flesh-colored skin lesion without epidermal invasion but with intracutaneous and subcutaneous spread. Pathologically, the tumor generally presents with an infiltrating dermal mass containing closely packed fibroblasts arranged in a storiform pattern. Several uncommon growth patterns have been described, including sclerosing, atrophic, myxoid, pigmented, giant cell-rich, granular cell, herringbone pattern and palisading/Verocay body-prominent forms. To our knowledge, only five cases of DFSP with nuclear palisading/Verocay body formation have been reported in the literature, and no t(17:22) translocation study has been done on these cases. In this report we describe such a case with negative t(17:22) translocation.

Dermatofibrosarcoma protuberans: from translocation to targeted therapy

Dermatofibrosarcoma protuberans (DFSP), the most common dermal sarcoma, is a low-grade, slow growing fibroblastic malignant neoplasm that most frequently affects middle aged adults and is characterized by a high local recurrence rate and a low propensity for metastasis. Wide surgical resection or Mohs micrographic surgery (MMS) are the preferred approaches for localized disease, while radiation therapy is warranted for inoperable disease or for cases with positive margins where re-excision is not possible. DFSP is generally regarded as refractory to conventional chemotherapy. Treatment options for systemic disease were limited until the discovery of a unique translocation, t(17;22)(q22;q13) (COL1A1;PDGFB) found in a majority of cases. In recent years, imatinib, a PDGFβR, ABL and KIT inhibitor, has revolutionized systemic therapy in DFSP. In this review, we summarize the epidemiological, clinical, histological and genetic characteristics of DFSP and update the readers on its current management.

A Clinicopathologic Review of a Case Series of Dermatofibrosarcoma Protuberans with Fibrosarcomatous Differentiation

Background:

Dermatofibrosarcoma protuberans with fibrosarcomatous differentiation (DFSP-FS) is a rare variant of DFSP with a more aggressive clinical course, characterized by higher rates of local recurrence, metastasis, and death.

Methods:

We conducted a clinicopathologic review of all DFSP-FS cases that occurred in Alberta, Canada, from 1997 to 2007.

Results:

Of the 75 DFSP cases reviewed, 4 demonstrated fibrosarcomatous differentiation. Three patients were female and one was male, and the age range was 25 to 76 years. Three tumors invaded to skeletal muscle, whereas one invaded to subcutaneous tissue only. Although perineural invasion was noted in all four cases, none exhibited lymphovascular space invasion. One local recurrence developed, and two of four tumors metastasized. Metastasis was associated with tumor size, tumor necrosis, grenz zone involvement, ulceration, thickness, and tumor grade. One patient died within 5 years of diagnosis.

Conclusion:

DFSP-FS represents a more aggressive subtype of DFSP. Several features of DFSP-FS may impart a higher risk of metastasis.

Braided pattern in a dermatofibrosarcoma protuberans: a potential mimicker of neural neoplasms

Dermatofibrosarcoma protuberans (DFSP) is a dermal and subcutaneous slow-growing tumor of intermediate malignancy. Different histological variants of DFSP have been described, depending on cellular and stromal peculiarities. Here, we report the histological features of a DFSP in which cells were frequently arrayed in cords and fascicles that were interweaved, conforming a peculiar braided pattern. This finding might pose difficulties in the differential diagnosis with neural neoplasms and expands the morphological spectrum of DFSP.

The wonderful colors of the hematoxylin-eosin stain in diagnostic surgical pathology

The hematoxylin-eosin (H&E) stain has stood the test of time as the standard stain for histologic examination of human tissues. This simple dye combination is capable of highlighting the fine structures of cells and tissues. Most cellular organelles and extracellular matrix are eosinophilic, while the nucleus, rough endoplasmic reticulum, and ribosomes are basophilic. This review discusses the spectrum, intensity, and texture of colors observed in H&E-stained slides to illustrate their value in surgical pathology diagnosis. Changes in color of the nuclei occur in the presence of nuclear pseudoinclusions (such as papillary thyroid carcinoma) or inclusions (such as viral infection, surfactant, immunoglobulin, and biotin). The color of the cytoplasm of spindly cells can provide clues to their nature, such as basophilic (fibroblast), eosinophilic (smooth muscle and others), and amphophilic (myofibroblast). Eosinophilic globules have diagnostic value for sclerosing polycystic adenosis of salivary gland, low-grade B-cell lymphoma, solid pseudopapillary tumor of pancreas, and inclusion body fibromatosis. Eosinophilic granules are characteristic of granular cells (lysosome-rich), oncocytic cells (mitochondria-rich), and cells with secretory products (including neuroendocrine cells). Eosinophilic crystals can be diagnostic of lymphoma/plasmacytoma and crystal-storing histiocytosis. Basophilic granules or inclusions are diagnostic of acinic cell carcinoma and malakoplakia (Michaelis-Gutmann bodies). Yellow or brown inclusions are characteristic of hyalinizing trabecular adenoma of thyroid (yellow bodies), brown bowel syndrome, and malignant melanoma. Extracellular eosinophilic deposits can be produced by many conditions, but amyloid and monoclonal immunoglobulin deposition disease are important considerations. Extracellular basophilic deposits may be seen in small cell carcinoma and systemic lupus erythematosus, but they differ in that the former is blue (nuclear material) while the latter is purple (nuclear material plus immunoglobulin).

A study on the prognostic value of clinical and surgical features of dermatofibrosarcoma protuberans in Korean patients

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare spindle cell tumour with locally aggressive characteristics. Only few studies on the epidemiology of DFSP in Asians have been reported.

OBJECTIVES

: The purpose of the study was to evaluate the epidemiological and clinical characteristics of DFSP in Korean patients and determine the prognostic factors that affect disease-free survival.

METHODS

We conducted a retrospective review of patients diagnosed with primary or recurrent DFSP between 2000 and 2009 at three Seoul National University Hospitals. Patient, tumour and treatment factors were analysed for local recurrence-free survival.

RESULTS

We analysed data for 65 patients, of whom 36 (55.4%) were female. The mean age at disease onset was 34.4 years with 50% aged between 20 and 40 years. Involved sites were most often on the trunk (66.1%). Among the 65 patients, 60 patients underwent wide excision; seven patients (10.8%) experienced local recurrence during 3.6 years of follow-up. The recurrence-free survival was significantly related to the microscopic resection margins (P = 0.005), clinical presentation (P = 0.002) and frequency of recurrence (P = 0.014) in the univariate analysis. There were three cases with metastasis, two of whom died because of progression of the disease despite continuous chemotherapy with imatinib mesylate.

CONCLUSIONS

We report the epidemiologic and clinical characteristics of DFSP in Korea. Patients with recurrent disease at presentation and frequent recurrence have a high risk of recurrence and metastasis, and therefore close observation is needed in these patients.

Granular cell atypical fibroxanthoma: case report and review of the literature

We present a case of granular cell atypical fibroxanthoma of the scalp. The neoplasm occurred as a tender nodule on the frontal scalp of an 82-year-old Caucasian man. Histology demonstrated a diffuse proliferation of atypical epithelioid cells with abundant granular cytoplasm. Many of the cells had large irregular nuclei and atypical mitotic figures were present. Immunohistochemical stains were positive for CD68 and procollagen 1 and negative for cytokeratin, HMB-45 and S-100 protein. The granular cell phenotype has been observed in other cutaneous neoplasms including granular cell tumors, dermatofibromas, dermatofibrosarcoma protuberans, fibrous papules, basal cell carcinomas, leiomyosarcomas, angiosarcomas and primitive polypoid granular cell tumors. We discuss the differential diagnosis and review the previously reported cases of this rare variant of atypical fibroxanthoma.

An infiltrative variant of non-neural granular cell tumor: a case report

Dermal non-neural granular cell tumors are rare tumors of indeterminate lineage that typically present as well-circumscribed tumors with nuclear pleomorphism and mitotic activity. We describe a dermal non-neural granular cell tumor with a distinctive growth pattern with granular cells interspersed between collagen bundles. This asymptomatic papule arose on the scapula of a 46-year-old woman and consisted of a mixture of epithelioid and spindled granular cells. The immunohistochemical characteristics were similar to those of previously reported dermal non-neural granular cell tumors. Despite mild nuclear pleomorphism and dispersion of lesional cells among collagen bundles, mitoses were not present and Ki-67 staining indicated a low proliferative rate. In addition to being S-100 protein negative and NKI/C3 positive, our case was positive for PGP9.5 and weakly positive for neuron-specific enolase, a staining pattern similar to what has been observed for cellular neurothekeomas. Our case could represent a dermal non-neural granular cell tumor with unique architecture, a granular cellular neurothekeoma or a granular cell dermatofibroma. As both dermal non-neural granular cell tumor and cellular neurothekeoma are of indeterminate lineage, our case with features characteristic of both entities may suggest a common precursor or lineage for dermal non-neural granular cell tumor and cellular neurothekeoma.

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.

Plexiform pattern in cutaneous granular cell tumors

Granular cell tumors, considered to be of peripheral nerve sheath origin, can involve various parts of the body with skin and tongue being the most common organs involved. In the skin, the granular cell tumors usually form an ill-defined mass of round to oval cells with abundant eosinophilic granular cytoplasm and central or eccentric bland nuclei. Here we present nine cases of granular cell tumors, which display features different from the classical cutaneous granular cell tumor and have features similar to the earlier described plexiform granular cell tumors. Plexiform pattern in granular cell tumors may be more common than is reported.

Fibrous papule of the face with granular cells

Fibrous papule of the face is a common benign lesion located most often on the nose. It presents usually as a single small, firm, skin-coloured papule and is often misdiagnosed as melanocytic naevus, wart or small nodular basal cell carcinoma. Histopathologically, the lesions are characterized by involvement of the upper dermis by a fibrovascular proliferation and scattered triangular or stellate, often multinucleated cells. Uncommon histopathologic variants of fibrous papule of the face include hypercellular, clear-cell, pleomorphic, pigmented, inflammatory and granular-cell types. We present here a patient with the syndrome of familial cancer and fibrous papule of the face with granular cells. The granules stained strongly with PAS stain, as well as with CD68 and NKI/C3 immunostains, whereas S-100 protein resulted negative. In our patient the mutations in the 2 most often affected DNA mismatch repair genes of Muir-Torre syndrome were not found, therefore the origin of the familial cancer syndrome remains unknown. Probably the occurrence of the granular-cell fibrous papule of the face was coincidental.

Myxoid dermatofibrosarcoma protuberans: clinicopathologic, immunohistochemical, and molecular analysis of eight cases

Dermatofibrosarcoma protuberans (DFSP) represents a locally aggressive mesenchymal neoplasm of skin and subcutis with characteristic clinicopathologic, immunohistochemical, and molecular findings. In addition to typical cases, morphologic variants such as pigmented, fibrosarcomatous, myofibroblastic, and granular cell DFSP have been described. Purely or predominantly myxoid DFSP is extremely rare, and may cause considerable diagnostic problems. Eight cases of predominantly myxoid DFSP were studied. Paraffin-embedded blocks and slides were retrieved from the files of the authors. Clinical data were obtained from the referring pathologists and dermatologists. Immunohistochemistry was performed using the ABC method, and three cases were studied by polymerase chain reaction technique. There were six male and two female patients (age range: 29 to 74 years). Locations included the inguinal area (three cases), thigh, upper arm, shoulder, abdominal wall, and back (one each). The patients were treated by wide excision as well as reexcision. Tumor size ranged from 1.5 to 12 cm. Histologically, a nodular growth with peripheral diffuse infiltration, as well as a diffusely infiltrating growth of relatively uniform spindled and stellated tumor cells containing slightly enlarged nuclei, was noted. Three cases were entirely myxoid, and in five cases more than 80% of the tumor area showed myxoid stromal changes. In two cases each, focal fibrosarcomatous and focal giant cell fibroblastoma-like changes were present. At least focally, hypocellular areas were evident in one case. Scattered enlarged tumor cells were seen in two cases. The mitotic rate ranged from 1 to 10 mitoses in 10 high-power fields. Numerous blood vessels with slightly fibrosed vessel walls were seen in seven cases. Immunohistochemically, tumor cells in all cases stained positively for CD34, and in one case each a focal expression of alpha-smooth muscle actin and epithelial membrane antigen (EMA) was noted. The remaining antibodies (CD99, CD31, S-100, Factor XIIIa) were all negative. Polymerase chain reaction technique showed in one case the characteristic COL1A1-PDGFB fusion gene. Follow-up information in seven cases (range: 2 months to 10 years; mean: 62 months; median: 48 months) revealed a local recurrence at 5 years. In conclusion, myxoid DFSP represents a very rare morphologic variant with characteristic changes that has to be distinguished from benign and malignant myxoid mesenchymal neoplasms as superficial angiomyxoma, superficial acral fibromyxoma, myxoid solitary fibrous tumor, myxoid perineurioma, low-grade myxofibrosarcoma, low-grade fibromyxoid sarcoma, myxoid liposarcoma, and myxoid synovial sarcoma.

Dermatofibrosarcoma protuberans

Dermatofibrosarcoma protuberans (DFSP) is a soft tissue neoplasm of intermediate malignancy that is initially localized to the skin from where it can invade deep structures (fat, fascia, muscle and bone). It is the most frequent fibrohistiocytic tumor, comprising approximately 1.8 % of all soft tissue sarcomas and 0.1 % of all cancers. It has an estimated incidence of 0.8-5 cases per one million persons per year. Treatment of localized disease consists in complete surgical excision of the lesion by conventional surgery with wide margins (>3 cm) or by micrographic Mohs surgery. Although the cases of metastatic DFSP do not reach 5 % of the total, almost all of them appear after previous local relapses. The prognosis for metastatic cases is very poor with a survival of less than 2 years following detection of metastatic disease. Patients with locally advanced DFSP are not candidates for an initial radical surgical therapy therefore neoadyuvant treatment is required prior to surgery in order to reduce tumor burden. In this regard, chemotherapy and radiotherapy have not been highly efficacious so it is necessary to consider new alternatives. The demonstration of the oncogenic power of the translocation COL1A1-PDGFB in DFSP has allowed the successful introduction of drug therapy with antagonists of the PDGFB receptor for metastatic or locally advanced cases.

Granular Cell Atypical Fibroxanthoma: Report of Two Cases

Two cases of an uncommon histopathological variant of atypical fibroxanthoma (AFX) are described. Even though both lesions presented as clinically conventional atypical fibroxanthoma, histopathology disclosed a neoplasm composed of cells with granular change that was negative for S100 staining, and showed prominent pleomorphism, severe nuclear atypia, and a high mitotic index. Degenerative change may explain the granular phenotype in these two cases of AFX. The differential diagnosis with primitive nonneural granular cell tumor is discussed.

Well-differentiated chondrosarcoma of the humerus with prominent granular cell component: a hitherto unreported occurrence

We report the case of a well-differentiated chondrosarcoma of the proximal humerus in a 60-year-old man that featured a prominent component of granular cells, the granules being shown by electron microscopy to be lysosomal. Although secondary granular cell changes have been described in a large variety of tumor types, this is, to the best of our knowledge, the first documentation of this phenomenon in a skeletal chondrosarcoma.

Sclerosing dermatofibrosarcoma protuberans (DFSP): an unusual variant with focus on the histopathologic differential diagnosis

A 59-year-old man presented with a 10-cm x 8-cm tumoral plaque with a superficial nodule in the interscapular region of the back (Fig. 1). The lesion had been growing for 25 years. As a cystic lesion was suspected, the superficial nodule was biopsied. The histopathologic diagnosis was low-grade sarcoma with sclerosis. Two months after the initial biopsy, the lesion was completely excised, reaching the muscular fascia, with a 2-cm margin and with a free graft. Formalin-fixed paraffin-embedded samples were submitted to histologic and immunohistochemical study (4-microm paraffin sections); frozen tissue was submitted to electron microscopy. For histopathology, sections were stained with hematoxylin and eosin. Immunohistochemistry was performed following standard avidin-biotin immunoperoxidase procedures with primary antibodies for vimentin, CD34, smooth muscle-specific actin, bcl-2, S-100, desmin, myoglobin, factor VIII, p53 (all from DAKO, Copenhagen, Denmark), HHF-35 (Enzo Diagnostics, Farmingdale NY), cytokeratin (AE1/AE3) (Biogenex, San Ramon, CA), and factor XIIIa (Calbiochem Novabiochem Corporation, La Jolla, CA). At low magnification, the histologic study of the initial tumoral nodule revealed a poorly circumscribed mesenchymal proliferation, with fibroblastic-like neoplastic cells arranged in a fascicular and storiform pattern, admixed with extensive areas of sclerosis. At higher magnification, tumoral cells were spindle-shaped with hyperchromatic nuclei and scant cytoplasm. In some areas, sclerosis was so evident that a keloid-like pattern was seen (Fig. 2a). The surgical specimen showed a fibroblastic neoplastic proliferation infiltrating the dermis and hypodermis. In the dermis, cells were arranged in a storiform pattern, whereas in the hypodermis there was a honeycomb or lace-like pattern (Fig. 2b). There were also cellular areas alternating with sclerotic areas, with transitional zones in between, in both the dermis and hypodermis. The immunohistochemical study of the initial tumoral nodule and the surgical specimen showed that tumoral cells expressed vimentin, CD34 (Fig. 3), bcl-2, HHF-35, and smooth muscle actin. Neoplastic cells failed to show positivity with desmin, myoglobin, factor XIIIa, factor VIII, S-100, cytokeratin (AE1/AE3), and p53. An ultrastructural study revealed spindle cells having an irregular contour with a well-developed granular reticulum endoplasmic (REG) system in their cytoplasm, as well as some Golgi complexes and mitochondria. Also visible was the presence of many actin filaments and some myosin condensations (Fig. 4), characteristics of a fibroblastic cell with myofibroblastic differentiation. The final histopathologic diagnosis of the surgical specimen was sclerosing dermatofibrosarcoma protuberans. Two years after surgery, the patient is alive and well.

Dermal non-neural granular cell tumour (so-called primitive polypoid granular cell tumour): a distinctive entity further delineated in a clinicopathological study of 11 cases

AIMS

Cutaneous and soft tissue granular cell tumour is a well-characterized benign neoplasm of neural origin. However, there remains a subcategory of granular cell tumour, first described by Le Boit as 'primitive polypoid granular cell tumour', that shows no obvious line of differentiation. The aim of this study is to further the characterization of this lesion by undertaking a clinicopathological review.

METHODS AND RESULTS

Eleven cases of dermal non-neural granular cell tumour were retrieved from one of the authors referral archives (E.C.) and both the histology and immunohistochemistry reviewed. Clinical data with follow-up were obtained from the referring pathologists. The lesions most commonly occurred in young to middle-aged adults (nine cases, median = 33 years, age range 6-56 years), with a slight female predominance. They presented as painless nodules, mainly on the extremities or face. Local excision was the treatment of choice and up to date follow-up reveals no sign of recurrence. Histologically, eight cases were polypoid, while three cases were endophytic. The tumours were composed of elongated spindle-shaped to polygonal or round cells with prominent granular cell change, and tumour nuclei showing mild focal atypia to rare moderate atypia. Mitotic activity ranged from one to nine mitoses per 10 high-power fields (median = 2, mean = 3.8). Immunohistochemical labelling of the tumour cells demonstrated expression for NKI-C3 (n = 11), focal, weak positivity for CD68 (n = 10) and FXIIIa (n = 2). There was negative staining for S100 protein, smooth muscle actin, Melan-A, CD34, desmin and cytokeratin.

CONCLUSIONS

This analysis of 11 cases contributes to the characterization of this recently described entity, which despite some atypical histological features and no obvious line of differentiation, behaves in a completely indolent fashion.

Primitive Nonneural Granular Cell Tumors of Skin

A rare subset of distinctive cutaneous nonneural granular cell tumors was described by LeBoit et al in 1991 and termed "primitive polypoid granular-cell tumor." Herein, we report our experience with 13 similar, distinctive nonneural granular cell tumors. Affected patients included 7 males and 6 females ranging in age from 5 to 83 years (mean, 25 years; median, 16 years). These cutaneous lesions involved the back (5 cases), neck, shoulder, thigh (2 cases each), chin, and elbow (1 case each). Clinically described as smooth, nontender cutaneous nodules, the tumors ranged in size from 0.2 to 2.8 cm (median, 0.8 cm) and were present from months to years before excision. Mitoses numbered from 1 to 6 per mm (median, 2). Eight of the lesions were polypoid, based in the papillary dermis with extension to the superficial dermis and associated with an epithelial collarette. Five of the lesions were situated deeper in the reticular dermis with limited extension into the subcutis but clinically were also nodular. All the tumors were well circumscribed and composed of spindled to ovoid cells with abundant granular, eosinophilic cytoplasm and vesicular nuclei with small prominent nucleoli. Immunohistochemistry revealed reactivity only for NKI-C3 (11 of 12 cases), CD68 (7 of 11 cases), and NSE (5 of 10 cases); S-100 protein as well as other melanocytic, epithelial, and myoid markers were uniformly negative. All 13 of the lesions were locally excised and in the 8 cases with adequate follow-up ranging from 13 to 126 months (mean, 68 months; median, 41 months), none has recurred locally. However, one tumor (case no. 11) gave rise to a local lymph node metastasis 25 months after presentation, but the patient is currently disease-free 70 months after lymphadenectomy. These cutaneous granular tumors do not appear to be neural or Schwannian in nature, but their precise line of differentiation is unknown.

Granular cell atypical fibroxanthoma

We report on two patients with granular cell atypical fibroxanthoma. Both neoplasms were solitary, light-tan, dome-shaped papules on sun-exposed areas of the head in two elderly white men. Microscopically, these neoplasms showed a dermal proliferation of pleomorphic granular cells with irregular hyperchromatic nuclei, multinucleated cells, and scattered mitoses. Immunohistochemical stains were positive for CD68 and vimentin and negative for Melan-A or human melanoma black (HMB)-45, S-100 protein, pancytokeratin, and actin, consistent with atypical fibroxanthoma. The differential diagnosis of granular cells in neoplasms containing cytological pleomorphism is challenging in view of the many different neoplasms that may present with granular cytoplasm. These include the conventional granular cell tumor and its malignant form, leiomyoma, leiomyosarcoma, dermatofibroma, dermatofibrosarcoma protuberans, and angiosarcoma.

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.

Dermatofibrosarcoma protuberans of the vulva and groin: detection of COL1A1-PDGFB fusion transcripts by RT-PCR

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is an uncommon infiltrative tumor of the dermis with characteristic cytogenetic features, specifically the translocation t(17;22)(q22;q13) which often manifests as a supernumerary ring chromosome r(17;22). The translocation results in the fusion of two genes, collagen type I alpha 1(COL1A1) and platelet-derived growth factor B-chain (PDGFB). The trunk and extremities are the anatomic sites of predilection for DFSP, whereas the vulva and groin are quite uncommon sites of involvement.

METHODS

This investigation evaluated seven DFSPs (four vulvar and three groin) for the presence of COL1A1-PDGFB fusion transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR), using archival formalin-fixed, paraffin-embedded tissue.

RESULTS

Six of seven cases (three vulvar, three groin) contained a COL1A1-PDGFB fusion transcript. Sequence analysis of the PCR products revealed that the break-point of the COL1A1 gene was located after exon 40 in two patients, after exon 42 in one patient, after exon 44 in one patient, and after exon 47 in two patients; the break-point in the PDGFB gene was before exon 2 in all cases. No fusion transcript could be amplified in one case.

CONCLUSIONS

As in DFSP at other sites, COL1A1- PDGFB chimeric fusion transcripts are present in vulvar and groin DFSP. The transcripts can be detected in formalin-fixed, paraffin-embedded tumor tissues, and have the same general pattern of exon boundaries as in DFSP at other sites.

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.

COL1A1-PDGFB fusion transcripts in fibrosarcomatous areas of six dermatofibrosarcomas protuberans

The fibrosarcomatous transformation of dermatofibrosarcoma protuberans (DFSP) has been considered for some time to be associated with an adverse clinical outcome. However, the molecular and cellular mechanism underlying the tumor progression remains undetermined. As the chimeric gene, COL1A1-PDGFB, has been proposed to play an important role in the histogenesis of DFSP, we conducted a reverse transcription-polymerase chain reaction assay to ascertain whether the COL1A1-PDGFB fusion transcripts can be detected in both conventional DFSP and fibrosarcomatous components of DFSP with fibrosarcomatous areas (DFSP-FS), using a simple method of microdissection on sections of archival formalin-fixed, paraffin-embedded tumor specimens from six DFSP-FS cases. The COL1A1-PDGFB fusion transcripts could be detected in FS areas in five of the six cases, whereas conventional DFSP areas of all cases expressed the chimeric mRNA. A subsequent sequence analysis of the polymerase chain reaction products confirmed that the detected messages were derived from identical gene fusions in the two different components of each of the five cases. Our results verify that the COL1A1-PDGFB fusion transcripts are preserved in the FS areas of most DFSP-FSs. The expression of the fusion transcripts in both conventional DFSP and FS areas of DFSP-FS supports a common histogenesis of the two components.

Granular Cell Variant of Atypical Fibroxanthoma

We report a case of atypical fibroxanthoma of the ear in which the dominant part of the tumor has granular cell appearance. Areas identical to conventional atypical fibroxanthoma were present only at the lateral infiltrating borders. Histologically the granular cells resembled those of the classical granular cell tumors but exhibited significant pleomorphism and a high mitotic rate. Immunostains for vimentin, CD68 and NK1/C3 were positive but for S-100, HMB-45, myogenic and epithelial markers were negative. The predominance of the granular cells in an atypical fibroxanthoma supports the concept that a small subset of tumors with granular cell phenotype are of nonneural origin.

Palisading and verocay body-prominent dermatofibrosarcoma protuberans: a report of three cases

The aim of this report is to draw attention to nuclear palisading and Verocay body formation as peculiar, previously undescribed histological findings in rare instances of dermatofibrosarcoma protuberans (DFSP).

METHODS AND RESULTS

Three indurated, nodular or plaque skin lesions were diagnosed as DFSP on the basis of their storiform proliferation of spindle-shaped cells diffusely infiltrating the dermis and subcutaneous tissue. Sclerosing and giant cell areas were also identified. Unexpectedly, conspicuous nuclear palisading was also noted in all cases and Verocay body formation was present in two. Immunostains were positive for CD34 and negative for S100 protein in every instance. Proliferating cells were seen to display fibroblast-like features by ultrastructural study of one case.

CONCLUSIONS

DFSP may rarely show a schwannoid histological appearance as the result of nuclear palisading and even Verocay body formation. In this setting, both the search for DFSP characteristic morphologic features and the performance of CD34 and S100 protein immunohistochemistry will facilitate the correct diagnosis.

Combined dermatofibroma: co-existence of two or more variant patterns in a single lesion

AIMS

Based on a series of 25 cases, we define and characterize combined dermatofibroma, a tumour comprising two or more variant patterns of dermatofibroma in a single lesion.

METHOD AND RESULTS

Dermatofibroma may present with a wide variety of architectural, cellular or stromal peculiarities. Architectural peculiarities include deep penetration, atrophy, collarette formation, fascicular to plexiform architecture, massive haemorrhage, prominent haemangiopericytoma-like vascularity and palisading; cellular peculiarities the presence of epithelioid cells, clear cells, granular cells, prominent myofibroblastic differentiation and atypical giant cells ('monster cells'); or stromal peculiarities such as prominent sclerosis, mucin, haemosiderin and cholesterotic deposits. In combined dermatofibromas two or more of these features are seen in complex or inhomogenous combination such as the silhouette of a deep penetrating dermatofibroma with an 'ordinary' storiform pattern in the upper and granular cell differentiation in the lower part of the lesion; or a dermatofibroma with ordinary features in the upper, prominent sclerosis in the middle and clear cells in the lower portion of the lesion; or the characteristic epidermal collarette and cells of epithelial cell histiocytoma with a plexiform ('neurothekeoma-like') architecture surrounded by a myxoid stroma with spindle-shaped to stellate cells. Clinically, these lesions preferentially occur on the lower extremities of young to middle-aged females, frequently with the diagnosis of a fibrohistiocytic lesion. Apart from one recurrence follow-up was uneventful in all other cases. Immunohistochemically, lesions are consistently positive with KiM1p, variably positive for factor XIIIa, smooth muscle specific actin and with KP1 (CD68), NK1C3 and E9.

CONCLUSION

Recognition of combined dermatofibroma allows the histopathologist to apply a confident benign label to unusual lesions which might otherwise elude diagnosis, or tempt description of 'new' entities and to avoid a misdiagnosis of malignancy.

Detection of COL1A1-PDGFB fusion transcripts in dermatofibrosarcoma protuberans by reverse transcription-polymerase chain reaction using archival formalin-fixed, paraffin-embedded tissues

The reciprocal translocation t(17;22)(q22;q13) and a supernumerary ring chromosome, r(17;22), derived from the translocation, have been shown to be highly characteristic of dermatofibrosarcoma protuberans (DFSP). Its consequence is a fusion of two genes, a collagen type I alpha 1 gene (COL1A1) and platelet-derived growth factor B-chain gene (PDGFB). The COL1A1-PDGFB fusion gene, is expected to be a diagnostic molecular assay. However, previous studies on this subject were mostly based on frozen tissue specimens or cultured tumor cells. In this present study, the investigators conducted a reverse transcription (RT)-polymerase chain reaction (PCR) assay to detect the COL1A1-PDGFB fusion transcripts using archival formalin-fixed, paraffin-embedded tumor specimens from 12 patients with DFSP. To amplify the fusion transcripts, a specific COL1A1 forward and PDGFB reverse primers were designed for single step PCR. The COL1A1-PDGFB fusion transcripts could be detected in 10 of 12 paraffin-embedded DFSP tumor specimens (83%). Subsequent sequence analysis using the PCR products confirmed that the detected messages were derived from gene fusions composed of PDGFB exon 2 and different regions of the COL1A1 gene (exon 8, 10, 22, 24, 32, 38, 45 or 46). Two samples of Bednar tumor included in this series also contained the fusion transcripts. In sample of DFSP with fibrosarcomatous transformation, the COL1A1-PDGFB could not be detected in the fibrosarcoma areas of the third recurrence, though the chimeric transcripts were identified in the ordinary DFSP areas of the first recurrence. No fusion transcripts could be amplified in non-DFSP lesions, including 10 dermatofibromas and 9 malignant fibrous histiocytomas. These results indicate that this molecular assay could be applied to archival formalin-fixed, paraffin-embedded tumor tissues as a diagnostic aid for DFSP.