Cases Of Atypical Fibroxanthoma Research Articles

Expression of 3q oncogene SEC62 in atypical fibroxanthoma-immunohistochemical analysis of 41 cases and correlation with clinical, viral and histopathologic features.

Atypical fibroxanthoma (AFX) is a rare mesenchymal tumor with predominance in older male patients located mainly in chronically UV-exposed skin. Differentiation from clinically more aggressive pleomorphic dermal sarcoma (PDS) is still under debate and immunohistochemical markers are not available yet. An immunohistochemical study, including 41 cases of AFX was conducted to investigate the expression of 3q encoded oncogene SEC62 in AFX and determine the associations with histomorphologic, clinical and viral parameters. Our cohort displayed a mean of 79.9 years at the onset of the disease. In total, 90.2% (37/41) AFXs were located in the head and neck area, whereas, four were located at the extremities (9.7%). Tumor diameter ranged between 0.06 and 40 cm2 with a mean of 5.7 cm2. SEC62 expression was markedly increased in lesional tissue compared with the adjacent healthy squamous epithelium. We found significantly higher expression of SEC62 in cases of AFX with tumor necrosis. Tendency of higher Sec62-IRS-scores were found for tumors with higher Clark levels and a tumor size >5 cm2. Sec62 is involved in endoplasmic reticulum stress tolerance and cell migration, and has been identified as a novel prognostic marker for non-small cell lung cancer as well as head and neck squamous cell carcinoma. For the first time, to the best of our knowledge, we suggest a role of 3q oncogene SEC62 in AFX and discuss a potential prognostic relevance in cases of disputable AFX with unfavorable histomorphologic features and may initiate a discussion on Sec62 serving as discriminating marker between AFX and PDS.

Multiple Fixed Drug Eruption Due to Piroxicam: A Brief Case Report

Atypical Fibroxanthoma (AFX) is a rare cutaneous mesenchymal neoplasm, predominantly found on sun-damaged skin of the head and neck in elderly patients. But uncommonly it can develop on a burn scar with or without actinic damage. Malignancy development is the major complication of severe burns and the term Marjolin's ulcer has been accepted clinically. The most common malignancy in this setting are Squamous Cell Carcinoma (SCC), followed by Basal Cell Carcinoma (BCC) and Malignant Melanoma (MM). Mesenchymal tumours especially malign forms quite infrequently seen on scar tissue. Herein, we present a rare and unusual case of AFX arising on the non sun-damaged area within a chronic burn scar of a young patient. Four cases of burn-related AFX reported in the literature are reviewed and the histopathological features and differential diagnosis are discussed.

Conception and Management of a Poorly Understood Spectrum of Dermatologic Neoplasms: Atypical Fibroxanthoma, Pleomorphic Dermal Sarcoma, and Undifferentiated Pleomorphic Sarcoma.

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) tumors share many clinical, etiologic, and histologic features and likely represent components of a tumor spectrum. In dermatologic oncology, differentiating between AFX and PDS is pivotal as tumors with histological features consistent with PDS are more likely to behave in a clinically aggressive manner. Importantly, the term "pleomorphic dermal sarcoma" (PDS) is a more appropriate designation than "undifferentiated pleomorphic sarcoma" (UPS) for describing deeper, more aggressive, histologically high-grade cutaneous tumors that otherwise resemble AFX. Surgery remains the gold standard for treatment. In the setting of AFX, excision with the Mohs micrographic technique appears to offer superior tumor control rates while maintaining greater tissue preservation over wide local excision and should be considered first line. In the setting of PDS, optimal management is less clear given the paucity of available data. However, due to its greater propensity to recur and metastasize, extirpation with complete tumor margin control appears paramount. The roles of imaging and SLNB in management and clinical outcomes of AFX and PDS are unclear given the lack of available data. In reality, these tools are unlikely to be helpful in most cases of AFX. However, in the setting of PDS, emerging literature indicates that these tumors are inherently higher risk, and thus, imaging and SLNB may be helpful in select cases. Additionally, radiation therapy may be of adjuvant benefit for these tumors when clear surgical margins cannot be obtained. While traditional chemotherapy has been largely ineffectual, the recent discovery of key oncogenetic mutations has allowed for the identification of several potential molecular drug targets that may have a therapeutic role with future study. In the unfortunate setting of metastatic disease, a multidisciplinary approach is optimal. Further studies are needed to establish definitive conclusions regarding risk stratification and best management practices.

Spindle Cell Atypical Fibroxanthoma: Myofibroblastic Differentiation Represents a Diagnostic Pitfall in This Variant of AFX.

Atypical fibroxanthoma (AFX) is a low-grade, dermal, mesenchymal neoplasm, which lacks a specific lineage of differentiation. The classical histologic appearance of AFX is that of a pleomorphic and spindle cell neoplasm with marked nuclear pleomorphism, mitotic figures, and often prominent storiform pattern that superficially resembles a pleomorphic high-grade sarcoma ("malignant fibrous histiocytoma"). Many histologic variants have been described. We have reviewed 15 cases of AFX characterized by a pure spindle cell morphology that could be easily mistaken for other spindle cell dermal neoplasms. All of our cases were stained with CD68, CD163, CD10, S-100p, p63, wide-spectrum keratin, CD31, CD34, smooth muscle actin (SMA), desmin, calponin, and h-caldesmon. All 15 cases showed an immunoprofile consistent with AFX. In 9 cases, SMA was also strongly expressed; this finding, coupled with the malignant spindle cell histomorphology, can lead to an erroneous diagnosis of cutaneous leiomyosarcoma with potential clinical consequences. Awareness of this pattern of immunoreactivity in this unusual variant of AFX is of importance for avoiding diagnostic misinterpretation. This study intends to characterize the nature and frequency of SMA immunoreactivity in AFX and to discuss the potential diagnostic pitfalls of immunohistochemical markers in distinguishing this entity from other malignant spindle cell neoplasms.

Atypical Fibroxanthoma of Scalp: A Paradoxical Benign Tumour.

Atypical fibroxanthoma (AFX) is a recently described soft tissue tumour by World Health Organization as a benign tumour of uncertain differentiation, occurring on sun exposed skin in elderly individual [1]. The bizarreness as well as marked atypia seen in the cells raises a first impression of malignant tumour, whereas it is rarely so. It has a male predominance (70%) with an average age of presentation of 71.9 years, ranging from 29–91 years [2]. An 81-year-old male presented with hard nodular scalp swelling since 7 to 8 years with a rapid size increase since 3 months. On examination there was a nodulo-ulcerative lesion measuring 5cm x 3cm on scalp with bleeding edges. He did not have any other cutaneous lesion or lymphadenopathy. Excisional biopsy done outside was reported as sebaceous carcinoma. The patient was referred to our hospital for further management. On review of biopsy slides, the tumour cells were spindled, plump to epithelioid with marked pleomorphism, arranged in haphazard, vaguely fascicular or storiform patterns [Table/Fig-1a]. Tumour cells had hyperchromatic and multilobulated bizarre nuclei with scattered multinucleate tumour giant cells. Some cells of the lesion contained vacuolated and lipid-containing cytoplasm similar to xanthoma raising doubts of sebaceous carcinoma, as diagnosed outside [Table/Fig-1b]. On extensive IHC work up, the tumour cells were positive for Vimentin (Dako;V9) [Table/Fig-1c], CD68 (Leica;514H12), CD10 (Dako;56C6) [Table/Fig-1d] and negative for Cytokeratin (Biogenix;AE1+AE3) [Table/Fig-1e], EMA (Dako, E29), SMA (Dako;1A4), S 100 (Dako;IS504), Desmin (Dako;D33), Caldesmon (Dako; H-CD) and HMB 45 (Dako;HMB45) [Table/Fig-1f]. A final diagnosis of atypical fibroxanthoma was made. [Table/Fig-1]: Histopathological examination showing large bizarre cells with abundant foamy cytoplasm and atypical mitosis (HE b) 400x). Immunohistochemistry showing positivity for Vimentin (c), CD10 (d) and negativity for Cytokeratin (e), HMB45 ... Making a diagnosis of atypical fibroxanthoma is challenging and the diagnosis should be made by exclusion of other differential diagnoses after applying the stringent histological criteria and a broad panel of immunostains. Cutaneous carcinomas and melanoma must be ruled out by immunohistochemistry. Absent immunostaining for cytokeratins, S100 and HMB45 in AFX are helpful for excluding sebaceous carcinoma along with squamous cell carcinoma and malignant melanoma. Other differentials are malignant fibrohistiocytoma, atypical Fibrous Histiocytoma /dermatofibroma with monster Cells and pleomorphic fibroma [Table/Fig-2]. By definition, in AFX tumour cells lack expression of S100, cytokeratin, CD34, desmin and h-caldesmon. Previously our case was misdiagnosed as sebaceous carcinoma due to pleomorphism, abundant clear to foamy cytoplasm and bizarre pleomorphic nuclei. CD10 is a useful marker for AFX and is positive in 95%–100% cases of AFX [2]. A histiocytic marker CD 68 is positive in more than half of cases [3]. AFX shows a very good prognosis after surgical excision [4]. Reports of metastasis are very rare, and recurrence is uncommon [5]. Distinction from high grade sarcoma is crucial to prevent inappropriate aggressive therapy. [Table/Fig-2]: Differential diagnoses of atypical fibroxanthoma

Atypical Fibroxanthoma の2例

Atypical Fibroxanthoma の2例

Atypical fibroxanthoma: Clinicopathologic determinants for recurrence and implications for surgical management

Atypical fibroxanthoma (AFX) is an uncommon skin tumor occurring primarily in the head and neck region of elderly Caucasian males. Treated with local excision, the disease is thought to be fairly benign but can occasionally demonstrate aggressive local recurrence as well as distant metastasis. Seventy-one cases of AFX were reviewed, representing all patients presenting to the Health Sciences Centre of South Eastern Ontario with the diagnosis of AFX in the period 1989-2008. Demographic and pathologic data were obtained from patient charts for analysis. Mean age at presentation was 76, with a male:female ratio of 4:1. Recurrence occurred in 10 patients after an average period of 7.3 months. Three recurrent lesions went on to distant metastasis, on average 14.3 months after initial presentation. The remaining 60 tumors did not recur. Histologically, tumor extending beyond the dermis into the underlying adipose and muscular tissue had a 29.4% chance of local recurrence and an 11.8% chance of metastasis compared to lesions confined to the dermis only (9.3% and 1.8%). While the majority of AFX presentations are benign, there is a real possibility of metastatic spread. Invasion beyond the dermis and a rapid rate of recurrence are suggestive of a more aggressive clinical course.

Atypical fibroxanthoma and malignant fibrous histiocytoma

Atypical fibroxanthoma (AFX) and malignant fibrous histiocytoma (MFH) are soft-tissue tumours with variable aggressiveness. There is considerable debate about the relationship between these lesions, as histological and immunochemical differentiation is difficult. Current opinions and evidence for diagnostic differences between AFX and MFH were reviewed. Consecutive cases of AFX and MFH were identified from our non-melanoma skin cancer (NMSC) database 1996-2007 for the Central Region of New Zealand. Of the 50,411 NMSC lesions excised surgically from 26,138 patients, there were 101 AFX and 15 MFH cases. Three MFH cases were originally diagnosed as AFX. AFX and MFH share similar patient demographics, size and location and histological and immunohistochemical features. Most diagnostic biopsies of AFX were not followed by formal excision. Incomplete excision occurred in a large proportion of patients with AFX, which often did not proceed to re-excision, resulting in local recurrence. Cases of MFH generally underwent definitive treatment including re-excision if incompletely excised, and postoperative adjuvant radiotherapy. The failure to treat AFX adequately may have resulted from the lack of appreciation of its aggressiveness. Contrary to the literature, we found few clinical differences between AFX and MFH. AFX and MFH also share similar histologic features and there are no immunohistochemical markers that reliably distinguish them. AFX is best considered a distinct entity with MFH, now reclassified as an undifferentiated pleomorphic sarcoma.

Myofibroblastic differentiation in atypical fibroxanthomas occurring on sun-exposed skin and in a burn scar: an ultrastructural and immunohistochemical study

Herein, we report the investigation of two cases of atypical fibroxanthoma (AFX). One AFX developed within actinically damaged skin, as is typical, while the other developed within a burn scar within non-sun-exposed skin. The two tumors showed almost identical histopathological, immunohistochemical and ultrastructural features. The tumors were composed of pleomorphic spindled, epithelioid, multinucleated and bizarre cells with enlarged atypical nuclei. Most tumor cells expressed vimentin and about 50% expressed CD10. Some tumor cells also expressed α-smooth muscle actin and CD68. However, there was no expression of cytokeratins, p63, S-100 protein, melan-A, HMB 45, desmin, epithelial membrane antigen or CD34. Ultrastructurally, the tumor cells contained myofilaments with dense patches but lacked plasmalemmal caveolae and basal lamina. The most prominent finding was the identification of fibronexus junctions. In addition, there were tumor cells containing numerous lysosomal granules. In conclusion, we clearly showed myofibroblastic differentiation in AFX by electron microscopy. We report also a case of AFX directly developing within a burn scar in the absence of actinic damage.

Detection of Merkel Cell Polyomavirus DNA in Atypical Fibroxanthoma in Correlation to Clinical Features

A clear etiopathogenetic concept for atypical fibroxanthoma (AFX) is not established yet. Nevertheless, AFX is known as a pleomorphic but indolent tumor primarily of the elderly and/or immunosuppressed patient occurring in severely sun- or radiation-damaged skin. These risk factors are almost identical to those of Merkel cell carcinoma (MCC), a highly malignant skin tumor being thought to be pathogenetically associated with the recently discovered Merkel cell polyomavirus (MCPyV). Because AFX and MCC share risk factors, the aim of this study was to evaluate presence of MCPyV DNA in 23 cases of AFX by PCR and direct DNA sequencing. Subsequently, we correlated clinical features with MCPyV DNA status in AFX. We detected MCPyV DNA in 4 of 23 AFX. All patients with MCPyV DNA-positive tumors were men. The mean age of patients with MCPyV DNA-positive AFX was 84.8 ± 8.7 years (vs. 75.2 ± 7.8 years of MCPyV DNA-negative AFX), the mean duration of tumor growth was 4.5 ± 2.3 months (vs. 5.1 ± 2.8 months) and the mean tumor diameter was 1.2 ± 0.3 cm (vs. 1.3 ± 0.7 cm). Ulceration was present in 75% of MCPyV DNA-positive tumors (vs. 65.2%). In conclusion, MCPyV DNA is present in 17% of AFX, in this cohort affecting predominantly male patients with higher age (>80 years). Clinical features seem to be independent of MCPyV DNA status. Although the role of MCPyV is unclear in this setting, it may act as a cofactor in the tumorigenesis of AFX in a subset of cases.

Keloidal and Other Collagen Patterns in Atypical Fibroxanthomas

Collagen deposition is observed in several cutaneous neoplasms and its derivation is variable. It can represent (1) a mesenchymal component of a biphasic tumor, (2) a desmoplastic host response to a neoplasm, or (3) a product of the tumor cells. The result is that collagenous (desmoplastic) variants of many cutaneous neoplasms are well recognized. In regard to atypical fibroxanthoma (AFX), conventional wisdom holds that intratumoral collagen is not commonly observed, apart from the rare sclerotic subtype of the neoplasm. This has not been our experience. The relatively frequent observation of keloidal collagen in AFXs and the dearth of information in the literature about this phenomenon prompted us to investigate the matter. All cases of AFX diagnosed at our institution within a 10-year period (1999-2008) were reviewed. The group included 64 males and 27 females with a mean age of 75 years. The majority of the cases (92%) were located on the head or neck. The conventional pleomorphic subtype of the tumor was encountered most frequently (67%). In 17 of the 91 cases (19%), prominent intratumoral keloidal collagen was present. This morphological observation poses interesting questions: (1) Is the collagen part of a host response to the neoplasm or is it a product of the tumor cells? (2) If the latter, does it cast light on the controversial histogenesis of AFX? (3) Does it signify an involutional stage of the tumor and imply a favorable prognosis? (4) Is it related to the "sclerotic" variant of the tumor? We discuss the above quandaries and emphasize the need to register this variant of AFX amongst other morphological subtypes of the tumor. The goal is to facilitate accuracy in diagnosis and to promote further investigation.

CD10, p63 and CD99 expression in the differential diagnosis of atypical fibroxanthoma, spindle cell squamous cell carcinoma and desmoplastic melanoma

Atypical fibroxanthoma (AFX) is a pleomorphic spindle cell lesion of the skin; it is considered in the differential diagnosis with spindle cell malignant melanoma (MM) and sarcomatoid carcinoma/spindle cell squamous cell carcinoma (SCC). An optimum approach has yet to fully emerge with respect to the immunohistochemical discrimination of these lesions. Departmental archives from 1978 onwards were searched for clinicopathologically confirmed cases of AFX, MM and SCC. Immunostains for CD10, CD99 and p63 were performed in each case. Scored staining results were analyzed using Fisher's Exact Test. Twenty-seven of 31 cases of AFX were positive for CD10, as compared with 3 of 22 SCCs and 0 of 20 MMs. CD10 positivity was preferentially associated with the diagnosis of AFX (p < 0.001). p63 reactivity was observed in 15/22 cases of SCCs, 5/31 AFXs and 1/20 MMs. CD99 reactivity was observed in 3/31 cases of AFX, 2/22 SCCs and 3/20 MMs. CD10 positivity is relatively specific in this context for the diagnosis of AFX. Its utility is enhanced when only strong, diffuse membranocytoplasmic staining is considered as a positive result. In contrast to prior reports, p63 was not found to be highly sensitive for SCC. Similarly, CD99 showed no preferential staining of any single diagnostic group of lesions.

Dermatoscopic features of cutaneous atypical fibroxanthoma: three cases

Atypical fibroxanthoma (AFX) is an uncommon, low-grade, malignant, spindle-cell tumour of fibrohistiocytic histogenesis, which can mimic other malignant skin tumours, such as basal and squamous cell carcinoma (CC), melanoma, and Merkel cell carcinoma (MCC). Three cases of AFX were examined by dermatoscopy, which revealed white areas and an atypical polymorphous vascular pattern characterized by the concurrence of different structures: linear, dotted, hairpin, arborescent and highly tortuous vessels, irregularly distributed over the surface. Seborrhoeic elements and photoageing may be accompanying features depending on the anatomical location of the AFX. AFX may be added to the list of slightly pigmented, reddish, malignant cutaneous tumours, such as SCC, MCC, amelanotic/hypomelanotic melanoma and eccrine porocarcinoma, which display prominent and chaotic dermatoscopic neoangiogenetic features in more advanced stages of proliferation.

CD117 Is Not a Useful Marker for Diagnosing Atypical Fibroxanthoma

Atypical fibroxanthoma (AFX) is a rare skin tumor that generally pursues an indolent course despite its alarming histological appearances. It is important for the pathologist to distinguish this neoplasm from more aggressive lesions that may show very similar histological features. Recently, it has been suggested that demonstration of CD117 is of value in identifying AFX. To test this hypothesis, 50 cases of AFX were stained immunohistochemically for CD117 to determine the diagnostic value of this antibody. Cases were also stained for tryptase to identify mast cells, which are CD117 positive. In addition, S100 and CD1a stains were performed to assess any possible contribution of melanocytes or Langerhans cells to CD117 staining. Only 1 of 50 AFXs (2%) showed CD117 positivity in the neoplastic cells, but all tumors demonstrated included CD117- and tryptase-positive mast cells in similar distribution. CD117 is only rarely stainable in the neoplastic cells of AFX and is therefore not useful in identifying these tumors. Mast cells are also CD117 positive, frequently present in AFX, and can lead to misinterpretation. Using immunohistochemistry for mast cell tryptase may be of value where there is doubt as to the nature of CD117-positive cells in neoplasms.

PR12 ATYPICAL FIBROXANTHOMA AND MALIGNANT FIBROHISTIOCYTOMA – A TEN‐YEAR REVIEW

Purpose: To review the clinical and histological differences between atypical fibroxanthoma (AFX) and malignant fibrohistiocytoma (MFH).Methodology: Cases of MFH and AFX were identified and histologically reviewed from our non‐melanoma skin cancer (NMSC) database 1996–2007 for the Central Region of New Zealand. Medline search and recent pathology textbooks were reviewed to determine current opinion and evidence for the diagnostic differentiation between AFX and MFH.Results: Of the 54,002 cases of NMSC, 103(0.2%) were histologically reported as AFX and 14(0.03%) MFH, with a mean age of 77 (range 51–93) and 74 (28–88) years respectively. The mean size of AFX was 16.3 (5–70) mm occurring on the head &amp; neck (n = 97), limb (n = 3), trunk (n = 2). 15 (14.7%) lesions were incomplete excised. 12 (11.7%) cases developed local recurrence and 1 metastasis. The mean size of MFH was 20.9 (range 7–50) mm occurring on the head &amp; neck (n = 10), trunk (n = 2), groin (n = 1) and limb (n = 1). 3 (21.4%) lesions were incompletely excised. 2(14.3%) patients developed local recurrence and 2 metastases. Local recurrence occurred in 12 (11.7%) cases of AFX and 2 (14.3%) cases of MFH. The literature states clinical and histological differences between AFX and MFH, but no immunohistochemical (IHC) stain reliably differentiates between them.Conclusion: Differentiating AFX from MFH based on histology and IHC is difficult and our cases did not conform to the typical presentation indicated in the literature. AFX and MFH are likely to belong to a spectrum of soft tissue sarcomas with variable aggressiveness.

INI1 and GLUT-1 Expression in Epithelioid Sarcoma and Its Cutaneous Neoplastic and Nonneoplastic Mimics

The morphological features of epithelioid sarcoma may closely mimic those of epithelial neoplasms, such as squamous cell carcinoma, mesenchymal tumors, such as benign fibrous histiocytoma, and nonneoplastic lesions, such as granuloma annulare. Immunohistochemistry, particularly for epithelial markers and CD34, thus plays a valuable role in the differential diagnosis of epithelioid sarcoma. However, some epithelioid sarcomas may show very focal or even absent expression of such markers and may be difficult to distinguish from various morphological mimics. There is therefore continued interest in the development of new immunohistochemical markers of epithelioid sarcoma. Recently, loss of expression of INI1, a tumor suppressor gene/protein, and expression of GLUT-1, a glucose transporter protein, have been described in epithelioid sarcoma. We examined the utility of immunohistochemistry for INI1 and GLUT-1 in the diagnosis of epithelioid sarcoma and various cutaneous mimics. Twenty-four cases of epithelioid sarcoma, 13 cases of granuloma annulare, 10 cases of rheumatoid nodule, 19 cases of cutaneous squamous cell carcinoma, 7 cases of atypical fibroxanthoma, 9 cases of benign fibrous histiocytoma (dermatofibroma), and 3 cases of nodular fasciitis were immunostained for GLUT-1 and INI1 using commercially available antibodies, heat-induced epitope retrieval, and the Dako Envision detection system. Total or near-total loss of normal constitutive expression of INI1 protein was noted in more than 85% of epithelioid sarcomas, with 19 of 24 cases (79%) showing complete loss of INI1 expression. In contrast, all other cases studied showed uniformly retained expression of INI1. GLUT-1 was positive in 40%-50% of epithelioid sarcomas, all cases of granuloma annulare and rheumatoid nodules, 67% of benign fibrous histiocytomas, and in all squamous cell carcinomas. In contrast, atypical fibroxanthomas and cases of nodular fasciitis were consistently GLUT-1 negative. We conclude that immunohistochemistry for INI1 expression should be included as part of the routine immunohistochemical panel for the diagnosis of epithelioid sarcoma, along with established markers such as wide-spectrum cytokeratins, cytokeratin 5/6, p63, and CD34. In this clinical context, loss of INI1 expression seems to be an entirely specific marker of epithelioid sarcoma and this finding may be of great value in distinguishing CD34-negative epithelioid sarcoma from squamous cell carcinoma and in the distinction of rare cytokeratin-negative epithelioid sarcomas from necrobiotic processes, nodular fasciitis, and benign fibrous histiocytomas. In contrast, there does not seem to be a role for GLUT-1 immunohistochemistry in this differential diagnosis.

Mutation analysis of the Gadd45 gene at exon 4 in atypical fibroxanthoma

BackgroundAtypical fibroxanthoma (AFX) histologically mimics high-grade sarcoma in the skin, although it follows a benign clinical course. AFX occurs in the sun-exposed skin and for this reason, an association with ultraviolet light has long been suspected. Bax and Gadd45 are p53 effector proteins. Bax is a programmed cell death protein and belongs to the Bcl-2 family. Gadd45 is a multifunctional DNA damage-inducible gene associated with the process of DNA damage.MethodsImmunohistochemical expression of Bax was analyzed in 7 cases of AFX, and in 7 cases of benign fibrous histiocytoma (BFH) used as a comparison. The expression pattern of Bax was compared to previously reported p53 and Gadd45 expressions in a correspondent series. Mutation of the Gadd45 gene at exon 4 was also analyzed in AFX.ResultsAFX and BFH showed immunoreactivities respectively for Bax (3/7, 0/7), Gadd45 (4/7, 1/7) and p53 (2/7, 0/7). There was no exact correlation between p53 expression and Bax or Gadd45 expression. However, the pattern of expression between Bax and Gadd45 was also the same, with the exception of one case. No mutation of the Gadd45 gene at exon 4 was observed in a series of 6 AFX cases where DNA was available (0/6).ConclusionThese results suggest a possible association between Bax and Gadd45 in AFX, and may refute any possibility of dysfunction of Gadd45 in terms of gene mutation, at least at exon 4 of the Gadd45 gene.

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.

CD99 immunoreactivity in atypical fibroxanthoma and pleomorphic malignant fibrous histiocytoma: a useful diagnostic marker

Atypical fibroxanthoma (AFX), a benign lesion, and pleomorphic malignant fibrous histiocytoma (MFH) are thought to represent points along the same neoplastic spectrum but with different prognoses and treatments. Diagnosis based on histology and clinical parameters alone is sometimes difficult, and a reliable cost-effective immunohistochemical marker to help distinguish these lesions would be beneficial. The diagnosis of AFX or MFH was based upon published clinical and microscopic criteria. Formalin-fixed, paraffin-embedded tissues of 17 cases of AFX and 26 cases of MFH were immunostained with monoclonal antibody to CD99. For all cases, CD99 expression was scored on a four-tiered scale: negative, weak (1+), moderate (2+), or strong (3+). Two pathologists blinded to tumor diagnoses and type of immunostain evaluated each case independently. The interobserver correlation coefficient was calculated. Seventeen patients with AFX (16 males and one female; mean age = 79) and 26 patients with MFH (16 males and 10 females; mean age = 60) were included. AFX lesions were from the head and the face, mean size = 1.5 cm, and MFH lesions were from the head, the neck, the trunk, and the upper/lower extremities, mean size = 5.2 cm. The 17 cases of AFX demonstrated moderate or strong (2 to 3+) immunoreactivity with CD99, compared to nine of 26 (35%) MFH cases (chi-square = 18.38; p < 0.001; interobserver correlation coefficient = 0.83). Of these, 16 of 17 (94%) AFX cases stained diffusely with CD99, while only four of 26 (15%) MFH cases stained diffusely. Control slides were adequate. Our study demonstrated that CD99 can help distinguish AFX from MFH, in addition to other immunohistochemistry as well as clinical and histologic criteria.

Atypical fibroxanthoma with perineural or intraneural invasion: report of two cases

We report two cases of atypical fibroxanthoma (AFX) that both had the previously unreported feature of neural invasion (one perineural and the other intraneural). AFXs recur in approximately 10% of cases but only rarely metastasize. Features associated with recurrence are inadequate excision and invasion into fat. Features associated with metastasis include recurrence, vascular invasion, deep tissue invasion, and tumor necrosis. Both of these tumors invaded deeply into subcutaneous fat and reached the deep fascia. Some authors would regard such cases as malignant fibrous histiocytoma (MFH) because of such deep extension; however, the concept of AFX as a superficial variant of MFH is outmoded--AFX is a distinct clinicopathologic entity with established clinical, histological, and immunohistochemical features.