A Case of Pleomorphic Dermal Sarcoma: Giant Exophytic Tumor of the Medial Canthus

We present the case of a 99-year-old Caucasian female who was referred for treatment of a painless, 8.0 cm × 7.8 cm exophytic, pedunculated, ulcerated tumor of the left medial canthus. Pathology showed spindled, oval, and polygonal cells with pleomorphic nuclei. Many multinuclear giant cells and mitotic figures were also noted. The tumor was highlighted with CD10, showed focal positivity with actin, desmin, and CD68, and had increased Ki67 immunohistochemical staining. The tumor was negative for pancytokeratin, CK5/6, p63, MART-1/MelanA, S100, Sox10, p40, CD34, and CD23. Based on clinicopathologic correlation, the diagnosis of pleomorphic dermal sarcoma (PDS) was made. Pleomorphic dermal sarcoma (PDS) refers to a deep, histologically high-grade tumor that often resembles other tumors clinically and histologically. As PDS is frequently aggressive and related to adverse outcomes, it is important to recognize its distinguishing features in comparison to other similar entities, including atypical fibroxanthoma (AFX) and pleomorphic leiomyosarcoma (PLMS). To our knowledge, there is only one other reported case in the literature of PDS occurring on the eye. By reviewing and understanding characteristic etiologies, locations of presentation, histopathological features, and management techniques, pathologists can make a more accurate diagnosis and dermatologists can provide more effective patient care in a timely manner.

Atypical fibroxanthoma and pleomorphic dermal sarcoma: Local recurrence and metastasis in a nationwide population-based cohort of 1118 patients

BACKGROUND

The prognosis of patients with atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) remains uncertain and no standardized follow-up programs have been established.

OBJECTIVE

To recommend a standardized follow-up program of patients with AFX and PDS based on nationwide long-term estimates of local recurrence and metastasis.

METHODS

All patients with AFX and PDS in Denmark between 2002 and 2022 were included. Danish National Registries were used to estimate the risks of local recurrence and metastasis for AFX and PDS.

RESULTS

The 5-year risk of local recurrence was 10% for AFX and 17% for PDS. The 5-year risk of metastasis was 0.8% for AFX and 16% for PDS. PDS metastasized within 3 years in >90% of the patients with the lungs as the primary metastasis site (50%). Invasion beyond the subcutis, perineural/intravascular infiltration, and increasing age significantly increased the risk of PDS relapse.

LIMITATIONS

Risk of misclassification and lack of detailed surgical information.

CONCLUSION

The follow-up of patients with AFX can be limited to clinical visits for 4 years. Patients with PDS should be followed with clinical visits and PET/CT twice a year for the first 3 years and once a year for a minimum of 1 year.

Pleomorphic Dermal Sarcoma With Metastasis to the Lung: A Case Report

ABSTRACT

Atypical fibroxanthoma and pleomorphic dermal sarcoma (PDS) are dermal malignant mesenchymal tumors that lie at the ends of the same disease spectrum. Clinically indistinguishable from atypical fibroxanthoma, PDS has a more aggressive course with significantly higher rate of local recurrence and metastases. Histological findings that favor a PDS include subcutaneous invasion, tumor necrosis, lymphovascular invasion, and/or perineural infiltration. Herein, we report a case of PDS with metastasis to the lung. Our report highlights the risk of local recurrence and metastatic spread in this cutaneous tumor and the importance of distinguishing this entity from its less aggressive counterpart.

Fine needle aspiration cytopathology of pleomorphic dermal sarcoma

INTRODUCTION

Pleomorphic dermal sarcoma (PDS) is an uncommon cutaneous mesenchymal neoplasm. It is cytomorphologically identical to atypical fibroxanthoma (AFX), but differs due to its invasion beyond the dermis. We undertook an examination of our experience with fine needle aspiration (FNA) biopsy cytology of PDS.

MATERIALS AND METHODS

Our cytopathology files were searched for examples of PDS with concomitant histopathological verification. FNA biopsy smears and cell collection were performed using standard techniques.

RESULTS

Seven cases of PDS were retrieved from four different patients (M:F, 1:1; age range: 63-88 years; mean age = 78 years). All patients (57%) presented with a primary tumour with one having an FNA biopsy of two local recurrences and a single distant metastasis. Five aspirates were from the extremities and two from the head/neck. Tumours ranged from 1.0 to 3.5 cm (mean, 2.2 cm). Specific cytological diagnoses were pleomorphic spindle/epithelioid sarcoma (3 cases), PDS (2), AFX (1), and atypical myofibroblastic lesion, query nodular fasciitis (1). Immunohistochemical (IHC) staining from FNA-generated cell blocks in two cases showed non-specific staining with vimentin in both cases; positive CD10, CD68, and INI-1 staining in one case; and smooth muscle actin expression in the other. Multiple negative stains were performed in both of these cases to exclude malignant melanoma, carcinoma, and specific forms of sarcoma. Cytopathology consisted of a mixture of spindle, epithelioid, and bizarre pleomorphic cells.

CONCLUSION

Coupled with ancillary IHC stains, FNA biopsy can help recognise PDS as a sarcomatous cutaneous neoplasm, but is unable to distinguish PDS from AFX.

Clinical and Dermoscopic Characteristics of Cutaneous Sarcomas: A Literature Review

Under the umbrella of cutaneous sarcomas (CS) we include a heterogeneous group of rare, malignant, mesenchymal neoplasia, such as dermatofibrosarcoma protuberans, atypical fibroxanthoma, cutaneous undifferentiated pleomorphic sarcoma, cutaneous angiosarcoma and leiomyosarcoma. Clinical presentation and histopathological examination are the cornerstone of CS diagnosis and classification. There are scarce data in the literature in regards to the clinical and dermatoscopic characteristics of CS and the role of dermatoscopy in their early identification. We performed a literature review, aiming to summarize current data on the clinical and dermatoscopic presentation of the most common types of cutaneous sarcomas that may facilitate early diagnosis and prompt management. Based on the available published data, CS are characterized by mostly unspecific dermatoscopic patterns. Dermatofibrosarcoma protuberans, Kaposi's sarcoma, and in a lesser degree, cutaneous angiosarcoma, may display distinct dermatoscopic features, facilitating their early clinical recognition. In conclusion, dermatoscopy, in conjunction with the overall clinical context, may aid towards suspicion of CS.

Atypical fibroxanthoma and pleomorphic dermal sarcoma - gene expression analysis compared with undifferentiated cutaneous squamous cell carcinoma

BACKGROUND

The histogenetic origin of atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) has not been definitively elucidated. In addition to a fibroblastic origin, a keratinocytic differentiation is discussed due to strong clinical, histomorphological and molecular genetic similarities with undifferentiated cutaneous squamous cell carcinoma (cSCC).

PATIENTS AND METHODS

56 cases (36 AFXs, 8 PDSs, 12 undifferentiated cSCCs) were evaluated for their clinical, histomorphological, and immunohistochemical characteristics. RNA transcriptome analysis was performed on 18 cases (6 AFXs/PDSs, 6 undifferentiated cSCCs, 6 differentiated cSCCs).

RESULTS

Clinically, the strong similarities in age, gender and tumor location were confirmed. Without further immunohistochemical staining, histomorphological differentiation between AFX/PDS and undifferentiated cSCC is often impossible. Principal component analysis of the RNA transcriptome analysis showed that AFX/PDS and differentiated cSCC each formed their own cluster, while the undifferentiated cSCCs fall in between these two groups, but without forming a cluster of their own. When examining differentially expressed genes (DEGs), the heat maps showed that there were cases within the undifferentiated cSCC that were more likely to be AFX/PDS than differentiated cSCC based on their expression profile.

CONCLUSIONS

The results provide evidence of molecular similarities between AFX/PDS and undifferentiated cSCC and suggest a common histogenetic origin.

Atypical Fibroxanthoma: Outcomes from a Large Single Institution Series

BACKGROUND

Atypical fibroxanthomas (AFX) are rare malignant cutaneous neoplasms. Unfortunately, limited clinicopathologic and outcomes data on this cancer exists.

OBJECTIVE

We report the clinical, pathologic, and treatment characteristics, as well as oncologic outcomes in this single-institution retrospective analysis.

METHODS

This retrospective cohort study compiled clinical, pathologic, treatment, and outcome data for all patients with AFX on definitive excision diagnosed, evaluated, and treated primarily by surgical resection at a single institution between 2000-2020. Descriptive statistics evaluated clinical and pathologic characteristics. Kaplan-Meier method and Cox proportional-hazards models were used to evaluate overall survival and recurrence-free survival.

RESULTS

78 patients with AFX were identified. The majority were elderly, immunocompetent, Caucasian men. 85% of tumors were located on the head and neck. 63% of patients were correctly diagnosed only after complete resection of the index lesion. The median surgical margin was 1.0 cm. Overall, only 1.3% (1/78) of patients developed a local recurrence (RFS). No patients died of disease.

CONCLUSION

This study suggests that resection margins of 1 cm achieve excellent local control with close to 99% RFS and 100% disease-specific survival.

[Atypical fibroxanthoma]

Atypical fibroxanthoma (AFX) is a rare skin tumor characterized by a combination of a «malignant» morphological features and non-aggressive clinical course. Diagnosing AFX is challenging due to histological «diversity» and heterogeneous immunophenotype. The presented review describes the history and evolution of AFX as a nosological form of cancer, its histogenetic origin, pathogenesis and biological potential. The clinical, morphological, immunohistochemical, molecular cytogenetic characteristics and histological subtypes of the tumor as well as differential diagnosis have been presented in detail.

A Rare Case of Atypical Fibroxanthoma of the Thigh in an Elderly Patient

Atypical fibroxanthoma (AFX) is a rare low-grade soft tissue tumor that manifests in sun-damaged skin on the head or neck of elderly patients, although it can occur anywhere else in the body. In this case, we report the presence of AFX on the right thigh of a 70-year-old white female. Upon presentation, she complained of a painless mass on her thigh with no family history of AFX or sun exposure. The mass had previously been managed by incision and drainage, with no improvement. The patient underwent a biopsy, revealing a diagnosis of AFX, which was managed by surgical removal of the neoplasm with appropriate safety margins.

Increase of atypical fibroxanthoma and pleomorphic dermal sarcoma: a retrospective analysis of four German skin cancer centers

BACKGROUND AND OBJECTIVES

In recent years, considerable insight has been gained into the pathogenesis, diagnosis and treatment of cutaneous sarcomas, including atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS). Both entities have shown increasing incidence rates in the last decade. This study was initiated to evaluate how these new insights impact the number of diagnoses of AFX/PDS compared to other cutaneous sarcoma entities.

PATIENTS AND METHODS

In a retrospective study of four German skin cancer centers, all histopathological reports of cutaneous sarcomas (AFX, PDS, dermatofibrosarcoma protuberans, cutaneous leiomyosarcoma, angiosarcoma, and Kaposi sarcoma) confirmed by board-certified dermatopathologists were analyzed during a time-period of seven years (2013-2019). Additionally, utilization of immunohistochemical markers (including pan-cytokeratin, S100, desmin, CD34, CD10, procollagen-1, CD99, CD14, and CD68) as an adjunct to diagnose AFX/PDS was recorded.

RESULTS

Overall, 255 cutaneous sarcomas were included in the present study. The diagnosis of a cutaneous sarcoma has consequently risen from 2013 to 2019 (from 16 to 52 annual cases). The results of AFX/PDS revealed 4.6 times more diagnoses in 2019 than in 2013. Atypical fibroxanthoma represented the most common subtype, displaying 49.3 % of all diagnosed cutaneous sarcomas. Additionally, the increase of AFX/PDS was linked to the use of immunohistochemistry, with specific immunohistochemical markers used in 57.1 % of cases in 2013 compared to 100 % in 2019.

CONCLUSIONS

This retrospective study of four German skin cancer centers demonstrates a substantial rise of AFX/PDS, possibly due to recently established diagnostic and terminology standards. This rise is probably linked to increased utilization of specific immunohistochemical markers. Atypical fibroxanthoma/PDS may be more common than previously thought and seems to represent the most frequent cutaneous sarcoma subtype.

Pleomorphic Dermal Sarcoma: A Clinical and Histopathologic Emulator of Atypical Fibroxanthoma, but Different Biologic Behavior

Description Pleomorphic dermal sarcoma (PDS) can clinically and histopathologically mimic atypical fibroxanthoma (AFX). However, it has a more aggressive clinical course with a higher recurrence rate and metastatic potential. This case presentation aims to report a rapidly-growing, exophytic, 4 cm tumor following a non-diagnostic shave biopsy 2 months prior and to highlight distinctive features between PDS and AFX needed to make the correct diagnosis. Like AFX, PDS occurs on the sun-damaged skin of the elderly, usually on the head and neck. Also, like AFX, PDS histopathologically consists of sheets or fascicles of epithelioid and/or spindle-shaped cells, often with multinucleation, pleomorphism, and numerous mitotic figures. Immunohistochemistry cannot distinguish PDS from AFX but is used to exclude other malignancies. PDS can be distinguished from AFX by size (PDS is usually >2.0 cm) and by the presence of more aggressive histopathologic features, such as subcutaneous involvement, perineural and/or lymphovascular invasion, and necrosis. PDS is a rare entity not well documented in the literature with confusing, misleading, and changing nomenclature. PDS is a diagnosis of exclusion made after complete excision of the tumor with the aid of histopathology and immunohistochemistry.

Clear cell variant of atypical fibroxanthoma and pleomorphic dermal sarcoma: molecular characterization and review of the literature

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are unusual cutaneous tumors that typically arise in sun-damaged skin of elderly individuals. Several histopathologic variants have been described, but the clear cell variant is particularly rare with only 18 cases of AFX and 1 case of PDS reported. Here, we present two cases of clear cell AFX and PDS highlighting key histopathologic findings and molecular alterations assessed by next generation sequencing (NGS).

Risk factors for local atypical fibroxanthoma recurrence and progression to pleomorphic dermal sarcoma: A meta-analysis of individualized participant data

Background

Risk factors for local atypical fibroxanthoma (AFX) recurrence and progression to pleomorphic dermal sarcoma (PDS) have not previously been identified.

Objective

To identify risk factors and provide follow‐up suggestions for local AFX recurrence and progression to PDS.

Methods and Materials

A literature search was performed in the PubMed, EMBASE, and Cochrane databases. The PRISMA and MOOSE guidelines were followed. The risks of local AFX recurrence and progression to PDS were presented as Kaplan–Meier plots and risk factors were presented as hazard ratios (HRs) calculated with univariate and multivariate Cox regression.

Results

Five hundred and ninety‐eight patients with AFX from 14 studies were included. Age >74 years and male sex significantly increased the risk of local recurrence (HR: 7.31 [95% confidence interval [CI]: 1.78–30.0], p < 0.01 and HR: 2.89 [95% CI: 1.04–8.01], p < 0.05, respectively). There was no difference when comparing wide local excision and Mohs' micrographic surgery (p = 0.89). The risks of local AFX recurrence and progression to PDS after 2 years were <1%.

Conclusion

A more intensive follow‐up regimen could be considered in patients >74 years old and males due to the higher risk of local AFX recurrence.

Cutaneous atypical fibroxanthoma with osteoclast-like giant cell: a rare phenomenon

Atypical fibroxanthoma with osteoclast-like giant cells is a rare entity. We present the case of an elderly woman who presented with a pink-purple dome-shaped nodule with central hyperkeratotic crust. Biopsy revealed a cellular, dermal based tumor comprised of spindle, oval, and osteoclast-like giant cells with pleomorphism. The immunohistochemistry profile supported a diagnosis of atypical fibroxanthoma (AFX) with osteoclast-like giant cells. We performed a literature review through PubMed and Google Scholar for AFX with osteoclast-like giant cell formation and found 16 previously reported cases. We aim to provide a review and discuss features of these cases. We also discuss the pathogenesis of these osteoclast-like cells as well as potential pitfalls in diagnosis. This article is protected by copyright. All rights reserved.

Atypical Fibroxanthoma Within a Melanoma: A Case Report

The finding of a pigmented lesion within another distinct lesion is rare but not unheard of. Here, we describe the presence of an atypical fibroxanthoma within a melanoma in a 72-year-old female referred to the plastics surgery department with a pigmented lesion on her left knee. It was excised in view of clinical suspicion of melanoma. The histopathology report documented a single lesion with two distinct components, namely a melanoma of superficial spreading type with a Breslow thickness of 3.0mm, and a central nodule of atypical fibroxanthoma.

Surgical excision margins for fibrohistiocytic tumors, including atypical fibroxanthoma and undifferentiated pleomorphic sarcoma: A probability model based on a systematic review

BACKGROUND

Mohs micrographic surgery or wide local excision is the treatment of choice for fibrohistiocytic tumors with metastatic potential, including atypical fibroxanthoma (AFX) and cutaneous undifferentiated pleomorphic sarcoma (cUPS). Since margin clearance is the strongest predictor of clinical recurrence, improved recommendations for appropriate surgical margins help delineate uniform excision margins when intraoperative margin assessment is not available.

OBJECTIVE

To determine appropriate surgical wide local excision margins for AFX and cUPS.

METHODS

Literature search (Ovid MEDLINE, Embase, Web of Science, and Cochrane Library from inception to March 2020) to detect case-level data. Estimation of margins required using a mathematical model based on extracted cases without recurrences.

RESULTS

Probabilistic modeling based on 100 cases extracted from 37 studies showed peripheral clearance margin (ie, wide local excision margin) calculated to clear 95% of all tumors was 2 cm for AFX and 3 cm for cUPS. AFX tumors 1 cm or less required a margin of 1 cm.

LIMITATIONS

Data were extracted from published cases.

CONCLUSIONS

Atypical fibroxanthoma removed with at least a 2-cm peripheral excision margin is less likely to recur. Smaller tumors 1 cm or less can be treated with a more conservative margin. Margin-control surgical techniques are recommended to ensure complete removal while minimizing surgical morbidity.

An Unusual Case of Desmoplastic Melanoma With Monster Cells Imitating an Atypical Fibroxanthoma

Numerous cells with very large and irregular nuclei ("monster" cells) have not hitherto been reported in desmoplastic melanoma (DM). Their prognostic significance in melanomas is a matter of debate, although some authors have associated them with more aggressive tumor behavior. We report a mixed DM on the scalp of an 88-year-old woman imitating an atypical fibroxanthoma. Tumor cells stained positive for SOX10, S100, and cyclin D1; BRAF mutation status was negative, and fluorescence in situ hybridization analysis showed copy number gains in 11q13 (cyclin D1) and 6p25 (RREB1), and loss in 6q23 (MYB). Cyclin D1 amplification is associated with poor prognosis in melanoma.

Pleomorphic dermal sarcoma: a retrospective study of 16 cases in a dermato-oncology centre and a review of the literature

BACKGROUND

Relatively little is known about the true aggressive potential of pleomorphic dermal sarcoma (PDS) or optimal management strategies.

OBJECTIVE

To describe the outcomes of 16 cases of PDS treated at our hospital (14 with modified Mohs micrographic surgery [M-MMS] and two with conventional surgery) and establish an adequate plan for management.

MATERIALS & METHODS

We reviewed 16 PDS cases treated at our hospital between October 2007 and June 2019 and compared our results with the available evidence.

RESULTS

In total, 69% of cases had recurred after initial conventional surgery, M-MMS led to local disease control in 83% of cases, and 19% of patients developed metastasis. Combining all published PDS cases with ours, we calculated an overall metastasis rate of 12%, and an overall recurrence rate of 35% after conventional surgery and 17% after M-MMS.

CONCLUSION

PDS is more aggressive than previously estimated, with an overall metastatic rate of 12%. Despite high recurrence rates with previous conventional surgery (69%), M-MMS achieved a good rate of local disease control (83%). Given the potential aggressivity of PDS and the importance of clear surgical margins, M-MMS appears to be more adequate than conventional excision. Staging studies and close monitoring are warranted in PDS patients, for which we propose a management algorithm.

Melanoma mimicking atypical fibroxanthoma: Report of an unusual case

Melanoma may mimic a variety of skin lesions clinically and histopathologically, and presents diagnostic challenges. In this article, we describe a case of melanoma in an 89-year-old man with a very rare histopathologic presentation, namely the presence of pleomorphic and multinucleated giant cells with abundant cytoplasm, highly resembling an atypical fibroxanthoma. The differential diagnoses in conjunction with the findings in immunohistochemical study are also discussed.

Evolution of a melanoma in situ to a sarcomatoid dedifferentiated melanoma

Sarcomatoid dedifferentiated melanoma (SDDM) is a recently recognized subtype of melanoma that stains diffusely for CD10 and lacks the expression of the usual melanocytic markers including S100, SOX10, MITF, and Melan A. Advances in next-generation DNA sequencing technology have facilitated the increased recognition of this rare, aggressive spindle cell melanoma. Herein, a case of relatively early lesion of SDDM arising in association with melanoma in situ is highlighted. A 72-year-old man with a history of previously treated melanoma in situ on the face five years prior presented with a new rapidly growing lesion within the scar of the treated site. A shave biopsy of the lesion revealed a centrally located 1.8-mm deep, poorly differentiated spindle cell neoplasm in association with an adjacent recurrent melanoma in situ. The spindle cell component stained diffusely for CD10, but failed to stain for S100, SOX10, and Melan-A while the melanoma in situ expressed all three melanocytic markers. Next-generation DNA sequencing assay revealed mutations in NF1, CDKN2A, TP53, and TSC1. A diagnosis of stage 2B SDDM arising in association with melanoma in situ was established based on the clinical context and genomic assay results.

Clinicopathological and Genomic Profiles of Atypical Fibroxanthoma and Pleomorphic Dermal Sarcoma Identify Overlapping Signatures with a High Mutational Burden

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are rare tumors developing in chronically sun-exposed skin. Clinicopathological features are similar, but they differ in prognosis, while PDS has a more aggressive course with a higher risk for local recurrence and metastases. In current clinical practice, they are diagnosed by exclusion using immunohistochemistry. Thus, stringent diagnostic criteria and correct differentiation are critical in management and treatment for optimal outcomes. This retrospective single-center study collected clinicopathological data and tumor samples of 10 AFX and 18 PDS. Extracted genomic DNA from tumor specimens was analyzed by a next-generation sequencing (NGS) platform (FoundationOne-CDx™). Among 65 identified mutations, TP53 inactivating mutations were observed in all tumor specimens. In both AFX and PDS, the known pathogenic gene alterations in CDKN2A, TERT promoter, and NOTCH1 were frequently present, along with high mutational burden and stable Micro-Satellite Instability status. The mutational profiles differed only in ASXL1, which was only present in AFX. Further differences were identified in likely pathogenic and unknown gene alterations. Similarities in their genomic signatures could help to distinguish them from other malignancies, but they are not distinguishable between each other using the FoundationOne-CDx™ NGS panel. Therefore, histological criteria to determine diagnosis remain valid. For further insight, performing deep tumor profiling may be necessary.

Atypical Fibroxanthoma: An unexpected cause of hemoptysis

Atypical fibroxanthoma is an infrequent, low-grade superficial cutaneous neoplasm, usually presenting as a nodule or plaque of red color. It is considered as a superficial variant of pleomorphic dermal sarcoma. Although atypical fibroxanthoma has similar histologic features to pleomorphic dermal sarcoma, it has less aggressive behavior. Atypical fibroxanthoma usually occurs on sun-exposed regions of the head and neck of elderly patients. Ultraviolet light, specific genetic mutations and administration of immunosuppressive agents to transplant recipients have been associated with the pathogenesis of the tumor. The prognosis is typically excellent when treated with complete excision of the primary lesion. This report describes the rare case of a 84-year-old man with hemoptysis due to metastatic cutaneous atypical fibroxanthoma.

Cutaneous mesenchymal tumors treated with Mohs micrographic surgery: a comprehensive review

Cutaneous mesenchymal tumors (CMT) are rare tumors with wide clinicopathologic heterogeneity. Treatment of malignant cutaneous mesenchymal tumors traditionally includes wide local excision (WLE), though Mohs micrographic surgery (MMS) has been increasingly used. A PubMed literature review of articles from inception until September 2019 related to malignant CMT and surgical treatment with MMS or WLE was completed. Dermatofibrosarcoma protuberans treated with MMS recurred in 1.2% of patients with no reported metastasis. Atypical fibroxanthoma treated with MMS recurred and metastasized in 2.7 and 2.5%, respectively. Undifferentiated pleomorphic sarcoma treated with MMS recurred in 32% with an unknown metastatic rate. Superficial leiomyosarcoma treated with MMS recurred in 3.8% with no reported metastasis. Cutaneous angiosarcoma and myofibrosarcoma treated with MMS have shown no recurrence or metastatic disease, but literature is sparse. The rarity of malignant CMT and the lack of comparative data on treatment make conclusive treatment recommendations difficult. However, recent literature suggests MMS is a useful option and potentially a superior treatment for primary cutaneous mesenchymal tumors.

Expression of connexin 43 by atypical fibroxanthoma

INTRODUCTION

Connexins are transmembrane channel proteins that interconnect adjacent cells and allow the exchange of signaling molecules between cells and the extracellular milieu. They have been investigated in many tumors to obtain information about tumor nature, behavior, and prognosis.

METHODS

Herein, we present a study on the immunohistochemical expression of connexin (Cx) 43 in 16 cases of atypical fibroxanthoma (AFX). For the immunohistochemical staining, a tissue array was obtained from the paraffin-embedded blocks.

RESULTS

The expression was membranous and cytoplasmic in all cases. Thirteen cases (81.25%) showed strong staining. In the other three cases (18.75%), the staining was medium. None of the cases showed nuclear staining. Fifteen out of 16 cases showed a diffuse pattern, and only one case showed a focal pattern.

CONCLUSIONS

Our results suggest that Cx43 may play an important role in the natural behavior of AFX.

Atypical fibroxanthoma and pleomorphic dermal sarcoma: A reappraisal

BACKGROUND

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) share clinical, pathological, immunohistochemical and molecular features, though PDS is associated with a more aggressive behavior.

METHODS

We reviewed 71 tumors fulfilling criteria for AFX and PDS to further stratify their biological potential.

RESULTS

Lesions were mainly located on the scalps of elderly men, and were often ulcerated. One case was necrotic, one showed vascular invasion, and one showed perineural invasion. Fifty-one tumors were limited to reticular dermis (71.8%), 20 invaded subcutaneous tissue, focally in 13 cases (18.3%), and diffusely in seven (9.9%). Subcutaneous invasion was present significantly more often in tumors showing predominantly spindle compared to pleomorphic/mixed cell morphology (P = 0.02). At a follow-up of 17-125 months, 4 cases recurred locally, 4, 6, 10 and 13 months after surgery; no metastases were observed. Three tumors were composed of spindle cells, and one of clear cells. Three cases had margins focally involved, while the fourth case had clear margins.

CONCLUSION

Depth of invasion and state of margins are criteria predicting prognosis in AFX/PDS; in addition, spindle cell morphology seems to be related to a more infiltrative pattern of growth and to aggressiveness. Grouping these tumors on a morphologic base could help to clarify their different biological behavior.

Atypical fibroxanthoma: An analysis of 105 tumors

Atypical fibroxanthoma (AFX) is a rare, low-grade dermal sarcoma. We analyzed our files from January 2001 to January 2020 for AFX. Clinical parameters, histopathology, treatment and outcome have been investigated. We identified 87 patients (mean age of 80.0 ± 8.4 years) with 105 confirmed tumors. Of these patients 86.2% were males. The most common clinical presentation was nodular (93.3%). The majority of AFX was located on the head with a mean tumor diameter of 15.0 mm ± 3.5 mm. All tumors showed a dermal localization, in 46.4% with a focal infiltration of the deeper layers. Second skin cancer was reported in 62.1% of patients. Collision tumors were seen in six patients. Treatment was surgical with three-dimensional margin control. Relapses were noted in 11.4% of tumors with a mean delay of 11.7 ± 17.3 months. Focally deeper infiltration of AFX was a risk factor (P = .014). None of the purely dermal AFX relapsed. No metastasis was observed. AFX is a rare mesenchymal tumor of elderly patients. Treatment of choice is the complete surgical excision. Due to the high rate of other skin malignancies among patients with AFX, a regular follow-up is recommended.

Atypical fibroxanthoma/pleomorphic dermal sarcoma of the scalp with aberrant expression of HMB-45: a pitfall in dermatopathology

Atypical fibroxanthoma (AFX) has been considered as the non-infiltrating precursor lesion of pleomorphic dermal sarcoma (PDS), which shows an aggressive clinical behavior, because of its extensive invasion of the deeper skin layers. Although these two tumors may represent two stages of the same disease, it can be difficult to differentiate between them, because of their similar clinical and histological features ¹. Furthermore, they must be distinguished from a spindled variant of squamous carcinoma, melanoma and leiomyosarcoma ². AFX/PDS still remains a diagnosis of exclusion, that needs to combine immunohistochemical markers for a definitive diagnosis. Usually AFX/PDS shows positivity for CD10, CD99, CD68, vimentin and lysozyme, while S100, HMB45, MART-1, cytokeratins, CD34, CD31, desmin and h-caldesmon are absent. We report a case of 89-year-old male, with a history of squamous cell carcinoma removed from the right ear, presented to our department with a recently growing, ulcerated and bleeding 2 cm nodule on the scalp. After surgery the tumor recurred with infiltration to the cranial theca. The final histological diagnosis was "pleomorphic dermal sarcoma" (PDS), which showed an unexpected positivity for HMB45. We present, to the best of our knowledge, the first case of AFX/PDS with an aberrant diffuse expression of HMB45 and an aggressive biological behavior, that leads us to a difficult exclusion diagnosis.

CD10 and p63 expression in a sarcomatoid undifferentiated melanoma: A cautionary (and molecularly annotated) tale

Undifferentiated melanoma should be considered in the differential diagnosis of sarcomatoid cutaneous malignancies to ensure that patients receive the correct treatment. Dermatopathologists should recognize the pitfalls of relying too heavily on immunohistochemistry to establish this diagnosis and consider ancillary tests, including single-nucleotide polymorphism (SNP) copy number arrays and targeted next-generation sequencing (NGS), when a definitive diagnosis cannot be rendered on a primary or metastatic tumor. This technology can also help to exclude a collision of melanoma and sarcoma when both differentiated and undifferentiated components are juxtaposed. We describe an exceedingly rare, illustrative example of undifferentiated sarcomatoid melanoma presenting as a pedunculated nodule. The clinical context and presence of a small differentiated component helped to establish the diagnosis; however, the transition from differentiated to undifferentiated melanoma was accompanied by an abrupt loss of S100, Sox10, MITF, MelanA, and HMB45 with gain of CD10 and p63 staining. SNP copy number array and NGS revealed shared chromosomal copy number changes and overlapping mutations with additional aberrances detected exclusively in the sarcomatoid component, thereby excluding a collision tumor and confirming our putative impression of melanoma with progression to an undifferentiated sarcomatoid phenotype.

Malignant Fibrous Histiocytoma of the Scalp with Skull Invasion: A Rare and Aggressive Presentation

Malignant fibrous histiocytoma (MFH) is an undifferentiated high-grade pleomorphic sarcoma and is considered the most common primary soft tissue sarcoma in adults. MFH is known to arise in the trunk, extremities and retroperitoneum although it can arise anywhere in the body.MFH of the skin is uncommon and even less frequent is the involvement of the scalp, especially with skull invasion. Most of the MFH cases present as a gradually growing lesion over a period of one to two years and is associated with ulceration and hemorrhage in most of the cases. Treatment of MFH is usually surgical resection.

We present a case of MFH in an 85-year-old gentleman that was invading the skull which required a multidisciplinary surgical treatment for resection and microvascular free flap reconstruction.

TLE1 expression fails to distinguish between synovial sarcoma, atypical fibroxanthoma, and dermatofibrosarcoma protuberans

Transducin-like enhancer of split 1 (TLE1) belongs to the Groucho/TLE/Grg family. It functions as a transcriptional corepressor and is widely used as a biomarker of synovial sarcoma (SS). Within the skin, atypical fibroxanthoma (AFX) and dermatofibrosarcoma protuberans (DFSP) often enter the histopathologic differential diagnosis. TLE1 expression has not been evaluated in these neoplasms. We examined archived tissues sections from the surgical pathology files from 10 adult patients diagnosed with AFX and 10 adult patients diagnosed with DFSP. We found nuclear staining in 10 of 10 AFX and 2 of 10 DFSP. We also noticed three patterns of staining in AFX: predominantly spindle component, predominantly epithelioid component, or mixed pattern of both epithelioid and spindle components. The group with the predominantly spindle pattern expressed the strongest nuclear TLE1 staining. In the DFSP group, one lesion demonstrated staining of epithelioid cells, with strong, diffuse nuclear TLE 1 expression, and the second lesion stained only the spindled cells, with weak nuclear TLE1 marking. In conclusion, TLE1, while a sensitive marker for SS, is not specific. A wide range of cutaneous spindle cell neoplasms also express TLE1. AFX and DFSP should be added to this list. TLE1 might be added to a diagnostic panel in this differential diagnosis.

Upper extremity pleomorphic dermal sarcoma in a patient with chronic myelomonocytic leukemia

BACKGROUND

Pleomorphic dermal sarcoma is a potentially high-grade cutaneous spindle cell tumor that closely resembles atypical fibroxanthoma in the superficial, dermal aspects but with adverse pathological features. Chronic inflammation, as several autoimmune disorders are co-associated with chronic myelomonocytic leukemia.

CASE DESCRIPTION

We report here an 84-year-old male patient with swelling lump on the upper third of the left arm. Previously he suffered from a type I chronic myelomonocytic leukemia. Based on the initial ultrasound-guided biopsy of the lesion, the histopathological examination revealed an atypical fibroxanthoma. A wide local excision was performed and the diagnosis was revised to pleomorphic dermal sarcoma by the pathologist, based on the currently accepted criteria. Adjuvant radiotherapy was performed.

CONCLUSION

Differentiating between atypical fibroxanthoma and pleomorphic dermal sarcoma is pivotal. A partial sampling of the skin lesion poses a significant pitfall, as important diagnostic features cannot be assessed. Immunosuppression seems to be involved in the pathogenesis of chronic myelomonocytic leukemia and pleomorphic dermal sarcomas, because of the advanced patient age. HIPPOKRATIA 2019, 23(4): 181-185.

Sarcomatoid Carcinoma With Quasi-Complete Loss of Cytokeratin Expression or Keratin-Positive Atypical Fibroxanthoma

We report the case of a 94-year-old man with a rapidly growing nodule on the preauricular area, which on histology showed a poorly differentiated spindle cell tumor with negative p63 and p40 antibody immunostains, negative high- and low-molecular-weight cytokeratins albeit for a focal expression of cytokeratin AE1/AE3. Spindle cell melanoma, angiosarcoma, and leiomyosarcoma were excluded. We explore the diagnostic approach to this challenging conundrum. Certain authors have suggested that sarcomatoid carcinoma and atypical fibroxanthoma (AFX) may lie within a spectrum of "sarcoma-like tumors of the head and neck" and that they may all run a similarly indolent clinical course. However, AFX appears to remain a diagnosis of exclusion, and expert consensus is that by definition AFX cannot express any cytokeratin antigens.

Expression of proton-sensing G-protein-coupled receptors in selected skin tumors

BACKGROUND

In humans, there are four known proton-sensing G-Protein-coupled receptors (pH-GPCRs): GPR4 (GPR19), TDAG8 (GPR65, T-cell death-associated gene 8), OGR1 (GPR68, ovarian cancer GPCR1) and G2A (GPR132, G2 accumulation protein). They are known to be involved in sensing changes of extracellular proton concentrations in the acidic microenvironment of tumors, which leads to altered cell proliferation, migration, metastasis, immune cell function and inflammation. However, little is known about the expression of pH-GPCRs in the skin and especially skin cancers.

AIM

We studied the expression of pH-GPCRs in selected skin cancers, that is Merkel cell carcinoma (MCC), dermatofibrosarcoma protuberans (DFSP), atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS).

METHODS

We did immunohistochemistry and immunofluorescence to analyse the expression of GPR4, TDAG8, OGR1 and G2A using paraffin-embedded tissue samples (n = 4, exceptions: PDS GPR4/GPR65 n = 5, AFX GPR132 n = 3) from patients suffering from MCC, DFSP, AFX and PDS.

RESULTS

(a) GPR4 was expressed on all AFX and PDS specimens. All AFX and MCC showed a positive expression of G2A. All PDS exhibited a strong positive expression of G2A. (b) MCCs neither expressed GPR4 nor TDAG8. All DFSP showed no expression of TDAG8. (c) For any other combination of GPCR and skin disease, we found positive/negative mixed results.

CONCLUSIONS

These are the first results on pH-GPCRs in selected skin cancers. We provide evidence that these GPCRs are differentially expressed on the various types of skin cancers and that they can potentially be addressed as a therapeutic target in extensive disease.

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.

Pleomorphic Dermal Sarcoma of the Scalp

Pleomorphic dermal sarcoma (PDS) is a rare mesenchymal tissue tumor. Distinguishing PDS from similar conditions, such as atypical fibroxanthoma (AFX), its less aggressive tumor counterpart, is difficult, as they are clinically and histologically similar. We present a case of a 77-year-old man presenting with a large nodular scalp lesion of three weeks duration. Pathology revealed a 3.3 cm invasive pleomorphic dermal sarcoma. Surgical excision with 2 cm margins was performed with successful healing of the graft. This case highlights a rare case of a large pleomorphic dermal sarcoma and discusses the histological features and management of PDS.

Atypical fibroxanthoma: Systematic review and meta-analysis of treatment with Mohs micrographic surgery or excision

BACKGROUND

Atypical fibroxanthoma (AFX) is a fibrohistiocytic tumor with relatively high local recurrence rates but low metastatic potential. Wide local excision (WLE) and Mohs micrographic surgery (MMS) are common treatments, although no consensus exists regarding optimal therapy.

OBJECTIVE

To systematically review evidence of AFX recurrence and metastatic rates after different surgical modalities.

METHODS

A comprehensive search was performed for articles published from 1946 or database inception to March 20, 2017. Studies selected included those that had 5 or more patients with atypical fibroxanthoma treated surgically. Two reviewers independently abstracted the data. Risk of bias was assessed with the Newcastle-Ottawa scale. Main outcomes and measures included recurrence and metastasis.

RESULTS

In total, 23 studies were selected (907 patients and 914 tumors); 175 patients were treated with MMS (recurrence rate 2.0%, 95% confidence interval [CI] 0%-4.1%; metastatic rate 1.9%, 95% CI 0.1%-3.8%), and 732 were treated with WLE (recurrence rate 8.7%, 95% CI 5%-12.3%; metastasis rate 1%, 95% CI 0.2%-1.9%). Among immunocompromised patients, no recurrence or metastases developed in the MMS subgroup, although 4 of 10 recurred and 1 of 10 metastasized in the WLE subgroup.

LIMITATIONS

Low quality of the studies published.

CONCLUSION

MMS for atypical fibroxanthoma is associated with a lower recurrence rate than WLE.

A tale of two clones: Caldesmon staining in the differentiation of cutaneous spindle cell neoplasms

BACKGROUND

We sought to compare the sensitivity and specificity of 2 different caldesmon antibodies in differentiating leiomyosarcoma from other cutaneous spindle cell neoplasms.

METHODS

Representative cutaneous spindle cell neoplasms were identified, including leiomyosarcoma, atypical fibroxanthoma, dermatomyofibroma and spindle cell squamous cell carcinoma. Immunohistochemistry was performed with antibodies directed toward caldesmon, smooth-muscle actin (SMA) and desmin. Sensitivity and specificity were calculated using grades from 3 independent observers.

RESULTS

The sensitivity of caldesmon (Ventana) was 100% (95% CI 78.2%-100%) and the specificity was 8.3% (2.8%-18.4%). Because this stain appeared to be non-specific, additional testing was performed on the same set of specimens using a second caldesmon clone (H-caldesmon, Dako), which had a sensitivity of 53.9% (25.1%-80.8%) and specificity of 96.6% (88.1%-99.6%). The sensitivity and specificity of SMA were 85.7% (57.2%-98.2%) and 84.5% (72.6%-92.7%), respectively. The sensitivity of desmin was 53.3% (26.6%-78.7%) with a specificity of 100% (94.0%-100%).

CONCLUSIONS

The Ventana caldesmon clone is not specific to smooth muscle, a potential pitfall to laboratories using this clone. The staining pattern, sensitivity and specificity of the Dako H-caldesmon antibody clone are similar to results from prior studies. The sensitivity and specificity of the Dako clone support its use in smooth muscle identification as an additional marker in challenging cases.

Dermoscopy features of atypical fibroxanthoma: A multicenter study of the International Dermoscopy Society

BACKGROUND/OBJECTIVES

Little is known about the dermoscopic features of atypical fibroxanthoma.

METHODS

This was a case-control study. Atypical fibroxanthoma lesions were compared with a control group with non-melanoma skin cancer.

RESULTS

Altogether 40 atypical fibroxanthoma were collected. Most developed in men (93%), appearing mainly as nodular (63%), amelanotic (93%) and ulcerated (78%) lesions. Most lesions were located on the scalp (55%) and the ears (13%). Dermoscopically, most atypical fibroxanthoma displayed red (83%) and white (70%) structureless areas and irregular linear vessels (43%). A series of features achieved statistical significance when comparing atypical fibroxanthoma with non-melanoma skin cancer. The presence of red and white structureless areas and white lines, and the absence of yellowish-white opaque scales, hairpin vessels and arborising vessels were predictive of atypical fibroxanthoma in univariate analysis. However, when squamous cell carcinoma was excluded from the analysis, none of the criteria achieved statistical significance. When basal cell carcinoma was excluded, three variables achieved statistical significance in predicting atypical fibroxanthoma: red, structureless areas, the absence of opaque yellowish-white scales and absence of white circles.

CONCLUSIONS

Atypical fibroxanthomas seem to be barely distinguishable from basal cell carcinoma dermoscopically, but they are more easily distinguishable from a well to moderately differentiated squamous cell carcinoma. A histopathological examination is needed for the final diagnosis.

Oncogene and therapeutic target analyses in atypical fibroxanthomas and pleomorphic dermal sarcomas

BACKGROUND

Until now, almost nothing is known about the tumorigenesis of atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS). Our hypothesis is that AFX is the non-infiltrating precursor lesion of PDS.

MATERIALS AND METHODS

We performed the world-wide most comprehensive immunohistochemical and mutational analysis in well-defined AFX (n=5) and PDS (n=5).

RESULTS

In NGS-based mutation analyses of selected regions by a 17 hotspot gene panel of 102 amplicons we could detect TP53 mutations in all PDS as well as in the only analyzed AFX and PDS of the same patient. Besides, we detected mutations in the CDKN2A, HRAS, KNSTRN and PIK3CA genes.Performing immunohistochemistry for CTNNB1, KIT, CDK4, c-MYC, CTLA-4, CCND1, EGFR, EPCAM, ERBB2, IMP3, INI-1, MKI67, MDM2, MET, p40, TP53, PD-L1 and SOX2 overexpression of TP53, CCND1 and CDK4 was seen in AFX as well as in PDS. IMP3 was upregulated in 2 AFX (weak staining) and 4 PDS (strong staining).FISH analyses for the genes FGFR1, FGFR2 and FGFR3 revealed negative results in all tumors.

CONCLUSIONS

UV-induced TP53 mutations as well as CCND1/CDK4 changes seem to play essential roles in tumorigenesis of PDS. Furthermore, we found some more interesting mutated genes in other oncogene pathways (activating mutations of HRAS and PIK3CA). All AFX and PDS investigated immunohistochemically presented with similar oncogene expression profiles (TP53, CCND1, CDK4 overexpression) and the single case with an AFX and PDS showed complete identical TP53 and PIK3CA mutation profiles in both tumors. This reinforces our hypothesis that AFX is the non-infiltrating precursor lesion of PDS.

Copy number variations in atypical fibroxanthomas and pleomorphic dermal sarcomas

Atypical fibroxanthomas (AFX) and pleomorphic dermal sarcomas (PDS) are frequent cutaneous sarcomas typically arising on sun-exposed skin in elderly patients. In contrast to AFX, which generally do not recur after complete excision, PDS locally recur in up to 50% and metastasize in up to 20%. We recently detected characteristic UV-induced TP53 mutations as potential driver mutation in almost all PDS investigated as well as activating PIK3CA and RAS gene mutations in around one third of our tumors representing targets for personalized treatments in patients with unresectable or metastasized PDS. In the present study, we identified amplifications and deletions in a small part of the PDS (6 of 27 cases) but not in AFX suggesting that copy number variations (CNV) might not be an initial event in tumor development but rather important during tumor progression. In addition to BRAF, KNSTRN, IDH1 and PDGFRA amplification, CNV analyses revealed deletions in the CDKN2A, KIT and PDGFRA genes. In cases where an appropriate FISH assay was established, the CNV results could be verified by FISH analysis. Amplification of BRAF, KIT or PDGFRA and/or losses of CDKN2A might represent bad prognostic markers, although larger studies are needed to clarify their association with prognosis or progression in PDS.

Clear-cell atypical fibroxanthoma: An unusual case in an unusual place

Atypical fibroxanthoma represents a low-grade sarcoma that usually presents in the elderly population on sun-damaged areas of the head and neck regions. This neoplasm is characterized on histology by atypical pleomorphic, epithelioid to spindled cells, arranged in a haphazard pattern, set within a background of solar elastosis. In this case report, we present a unique case of the rare variant of clear-cell atypical fibroxanthoma arising in an unusual place, specifically the lower extremities.

Granular cell differentiation: A review of the published work

Since the initial description of the granular cell tumor in 1926, numerous other neoplasms, both benign and malignant, have been described to exhibit granular cell change. In most cases, diagnosis remains straightforward via recognition of retained histopathological morphology of the archetypal tumor, despite the presence of focal granular appearance. However, tumors with granular cell differentiation can present a diagnostic challenge either by mimicking alternative diagnoses, or by failing to exhibit architectural clues of the primary entity, thus requiring an immunohistochemical work-up. In light of this, it is important to be aware of the various entities that have been reported to exhibit granular cell morphology. In this review such tumors are discussed along with pertinent clinical and histopathological features.