More than 2 decades of treating atypical fibroxanthoma at mayo clinic: what have we learned from 91 patients?

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.

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.

Atypical Fibroxanthoma Resected without Auricular Deformity in an Elderly Patient: A Case Study

Atypical fibroxanthoma (AFX) is a dermal spindle-cell cutaneous malignancy, which is a relatively benign type of skin cancer that occurs in the elderly with sun-damaged skin. This is a case study of a rapidly enlarged left auricular mass lesion in an elderly patient who was diagnosed with AFX based on histopathological and immunohistochemical findings, and then treated by complete excision to prevent recurrence or metastasis. There was no recurrence during the 1-year follow-up. For otolaryngologists or plastic surgeons, recognizing the clinical and pathologic characteristics of AFX is important for accurate diagnosis and treatment.

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.

Progression of the atypical fibroxanthoma to pleomorphic dermal sarcoma in a heart transplant patient

An 82-year-old man presented with a right scalp lesion which had been increasing in size. The patient's medical history was significant for a heart transplant 25 years before, and he was on chronic immunosuppression. Biopsy of the lesion showed atypical fibroxanthoma. The patient underwent an excision of the lesion with split thickness skin graft. Pathology showed fibroxanthoma with negative margins. Over the next 9 months, the patient developed new lesions, which were also excised to negative margins. However, with each new lesion, the histology demonstrated increasing dysplasia and ultimately pleomorphic sarcoma. The patient had a metastatic workup with CT of the chest, which was negative, and he underwent a radical scalpectomy, split thickness skin graft placement and adjuvant radiation therapy. The patient has not developed any new scalp lesions and no evidence of metastasis.

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.

Locally Advanced Pleomorphic Dermal Sarcoma of the Forearm

Pleomorphic dermal sarcoma (PDS) is a rare mesenchymal tissue tumor that shares pathological features with atypical fibroxanthoma, but also exhibits tumor necrosis, invasion beyond the superficial subcutis, and vascular or perineural infiltration. In addition, PDS also has relatively high rates of local recurrence and metastasis and is usually encountered in elderly men, especially in the head and neck area. In this article, we report a rare case of PDS that infiltrated the fascial tissues in the forearm of a female patient. After wide local excision, the defect was covered with an anterolateral thigh free flap and adjuvant radiotherapy was instituted.

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.

Pleomorphic dermal sarcoma: a clinical and histological review of 49 cases

Pleomorphic dermal sarcoma (PDS) is a rare mesenchymal neoplasm that shares histopathological features with atypical fibroxanthoma (AFX), but has additional features of deep invasion of the superficial subcutis, tumour necrosis, and vascular and perineural invasion, which confers a risk of local recurrence and metastases. To study the clinical and pathological spectrum more comprehensively, we retrieved 49 cases of pleomorphic dermal sarcoma from our departmental files. There was a strong male predominance (n=45). The mean (range) age at presentation was 80 (47-97) years. The tumours had a median (range) maximum dimension of 23.5 (5-75) mm. There was a strong predilection for the head and face (n=47), with the scalp (n=32) being the most common site. Ulceration was observed in 21 patients, tumour necrosis in seven, perineural infiltration in six, and lymphovascular invasion in two. CD10 was expressed in all cases. Smooth muscle actin was expressed in 15 and CD68 in 14. Follow up was available in 41 cases (mean (range) 22.4 (2-90) months). Six patients had local recurrences, despite all having originally undergone primary surgical resections and having reports of clear margins. Progressive metastatic disease was observed in one patient who died from their disease. Based on the Kaplan Meier method, median overall survival was 70.8 (8.4-133.1) months. Although AFX and PDS may be part of a spectrum, distinction is important to emphasise the potential for malignant behaviour in PDS.

Nonmelanoma Skin Cancer

This article reviews the most common nonmelanoma skin cancers affecting the head and neck region. Although the most common of these malignancies rarely result in mortality, local morbidity caused by the tumors and their extirpation cannot be underestimated. Complete tumor extirpation with pathologically confirmed negative margins is the gold standard. Regional and distant metastases are rare, but must be treated appropriately should they occur. Although reconstructive surgery can be life changing for the patients and rewarding for the clinicians, it behooves the treating surgeons to remain true to oncologic principles above all else.

Patient indications for Mohs micrographic surgery: a clinical practice guideline

Objective

The purpose of the present work was to develop evidence-based indications for Mohs micrographic surgery in patients with a diagnosis of skin cancer.

Methods

The guideline was developed by Cancer Care Ontario's Program in Evidence-Based Care, together with the Melanoma Disease Site Group and the Surgical Oncology Program, through a systematic review of relevant literature, patient- and caregiver-specific consultation, and internal and external reviews.

Recommendation 1

Given a lack of high-quality, comparative evidence, surgery (with postoperative or intraoperative margin assessment) or radiation (for those who are ineligible for surgery) should remain the standard of care for patients with skin cancer.

Recommendation 2

Mohs micrographic surgery is recommended for patients with histologically confirmed recurrent basal cell carcinoma of the face and is appropriate for primary basal cell carcinomas of the face that are larger than 1 cm, have aggressive histology, or are located on the H zone of the face.

Recommendation 3

Mohs micrographic surgery should be performed by physicians who have completed a degree in medicine or equivalent, including a Royal College of Physicians and Surgeons of Canada Specialist Certificate or equivalent, and have received advanced training in Mohs micrographic surgery.

Patient Indications for Mohs Micrographic Surgery: A Systematic Review

The purpose of the present review was to describe evidence-based indications for Mohs micrographic surgery (MMS) in patients with a diagnosis of skin cancer. Relevant studies were identified from a systematic MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews search of studies published from 1970 to 2017. Randomized controlled trials (RCTs), prospective and retrospective comparative studies with greater than 30 patients, and single-arm retrospective studies with multivariate analyses were included. A total of 2 RCTs, 3 prospective studies, and 16 retrospective studies (14 comparative and 2 single-arm) were included. Data on recurrence rate, cure rate, complications, cosmesis, and quality of life were extracted. Surgery (with postoperative or intraoperative marginal assessment) or radiation for those who are ineligible for surgery should remain the standard of care for patients with skin cancer given the lack of high-quality, comparative evidence. MMS is recommended for those with histologically confirmed recurrent basal cell carcinoma (BCC) of the face and is appropriate for primary BCCs of the face that are >1 cm, have aggressive histology, or are located on the H zone of the face. The available evidence is difficult to generalize to all patients with skin cancer because the evidence did not adequately cover non-BCC skin cancers; however, those skin cancers can be considered on a case-by-case basis for MMS. MMS should be performed by physicians who have completed a degree in medicine or equivalent, including a Royal College of Physicians and Surgeons of Canada Specialist Certificate or equivalent, and have received advanced training in MMS.

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.

Mohs Micrographic Surgery: Development, Technique, and Applications in Cutaneous Malignancies

Mohs micrographic surgery (MMS) is a specialized technique for treating skin malignancies that offers the highest cure rate by allowing histological evaluation of the entire peripheral and deep margins. MMS also maximally preserves as much uninvolved, normal adjacent tissue as possible, allowing for the best cosmetic and functional outcomes. When used for appropriate indications, this technique is also more cost-effective than other treatment modalities. In this article, the authors will discuss the development of MMS, the steps involved in this procedure, and the indications for this technique. They will also review the use of MMS for basal cell carcinoma, squamous cell carcinoma, melanoma in situ, and some less common skin malignancies.

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

OPINION STATEMENT

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.

Understanding Mohs Micrographic Surgery: A Review and Practical Guide for the Nondermatologist

The incidence and diagnosis of cutaneous malignancies are steadily rising. In addition, with the aging population and increasing use of organ transplant and immunosuppressive medications, subsets of patients are now more susceptible to skin cancer. Mohs micrographic surgery (MMS) has become the standard of care for the treatment of high-risk nonmelanoma skin cancers and is increasingly used to treat melanoma. Mohs micrographic surgery has the highest cure rates, spares the maximal amount of normal tissue, and is cost-effective for the treatment of cutaneous malignancies. As in other medical fields, appropriate use criteria were developed for MMS and have become an evolving guideline for determining which patients and tumors are appropriate for referral to MMS. Patients with cutaneous malignancies often require multidisciplinary care. With the changing landscape of medicine and the rapidly increasing incidence of skin cancer, primary care providers and specialists who do not commonly manage cutaneous malignancies will need to have an understanding of MMS and its role in patient care. This review better familiarizes the medical community with the practice of MMS, its utilization and capabilities, differences from wide excision and vertical section pathology, and cost-effectiveness, and it guides practitioners in the process of appropriately evaluating and determining when patients with skin cancer might be appropriate candidates for MMS.

Borderline Sarcomas and Smooth Muscle Tumours of Uncertain Malignant Potential

Borderline sarcomas and smooth muscle tumours of uncertain malignant potential (STUMP) have an unpredictable clinical behaviour with frequent local recurrences and rarely, metastases. We review the current management of common subtypes of borderline sarcomas and STUMP.

Incidence and Clinical Features of Rare Cutaneous Malignancies in Olmsted County, Minnesota, 2000 to 2010

BACKGROUND

The incidence of rare cutaneous malignancies is unknown. Current estimates of rare cutaneous malignancy incidences are based on broad epidemiologic data or single institution experiences, not population-based data.

OBJECTIVE

To determine the incidence of several rare nonmelanoma skin cancers.

MATERIALS AND METHODS

The authors conducted a retrospective chart review of a population-based cohort between the years 2000 and 2010. Residents of Olmsted County, Minnesota, who were diagnosed with a biopsy-proven nonmelanoma skin cancer-excluding basal cell carcinoma and squamous cell carcinoma-were included in this study. The primary outcome was tumor incidence. Additionally, the authors extracted patient demographics, tumor characteristics, treatment modalities, and outcomes.

RESULTS

The age-adjusted and sex-adjusted incidences per 100,000 persons of multiple rare cutaneous malignancies were: atypical fibroxanthoma (1.8), sebaceous carcinoma (0.8), dermatofibrosarcoma protuberans (0.4), microcystic adnexal carcinoma (0.7), eccrine carcinoma (0.4), eccrine porocarcinoma (0.2), and leiomyosarcoma (0.2).

CONCLUSION

The authors report population-based incidences and clinical characteristics for these rare cutaneous malignancies. The immune status and smoking status of patients and the treatment and outcomes of these tumors are reported. Additional studies in a broader population are needed to further define the epidemiology and outcomes of these malignancies.

Electronic brachytherapy management of atypical fibroxanthoma: report of 8 lesions

Purpose

To evaluate the suitability of treating atypical fibroxanthoma (AFX), an uncommon skin malignancy, with electronic brachytherapy.

Material and methods

From Feb 2013 to Sep 2014, we were referred a total of 8 cases of AFX in 7 patients, all involving the scalp. All of them were treated with electronic brachytherapy 50 Kev radiations (Xoft Axxent^®, Fremont, California). All lesions received 40 Gy in two fractions per week with 5mm margins.

Results

At a median follow-up of 23.7 months, the local recurrence rate is 12.5%. The single lesion that failed was not debulked surgically prior to electronic brachytherapy.

Conclusions

To our knowledge, this is the first report in the literature on the use of radiation therapy as curative primary treatment for AFX. No contraindication to the use of radiations is found in the literature, with surgery being the sole treatment for AFX noted. Our recurrence rate is 0% for debulked lesions. Risk of recurrence is mitigated with surgical debulking prior to brachytherapy. Electronic brachytherapy appears to be a safe and effective treatment for debulked AFX. Multiple excisions, skin grafting, and wound care can be avoided in elderly patients by the use of electronic brachytherapy.

Case of Pleomorphic Dermal Sarcoma of the Eyelid Treated with Micrographic Surgery and Secondary Intention Healing

Pleomorphic dermal sarcoma (PDS) is a rare mesenchymal neoplasm sharing histopathological features with atypical fibroxanthoma (AFX), but has additional features of deep invasion of the superficial subcutis, tumor necrosis and vascular/perineural invasion. It is not well documented in the literature because of its rarity, and its clinical course has been debated due to the lack of homogenous criteria. We describe here the case of a 91-year-old female with a 6-month history of a solitary, asymptomatic, well-defined, 3.4-cm-sized, reddish, hard, protruding mass on the lateral aspect of the right upper eyelid. On the basis of initial punch biopsy results, storiform cellular infiltrate of pleomorphic spindle and polygonal cells with frequent atypical mitoses, the lesion was identified as AFX. Following the initial biopsy, micrographic surgery was performed and a tumor-free margin was confirmed. Considering the conservation of the periocular function and the advanced age of the patient, we planned secondary intention healing rather than primary suturing. After surgery, skeletal muscle infiltration was found and the diagnosis was revised to PDS by a pathologist based on the currently accepted criteria for PDS. There has been no evidence of recurrence or periocular functional defects during a 2-year follow-up without adjuvant therapy. Although the PDS is highly malignant, complete excision under micrographic surgery can prevent recurrence without adjuvant therapy. Also, the secondary intention healing is an effective method for closure of large defects on the face.

Keloidal Atypical Fibroxanthoma: Case and Review of the Literature

Keloidal atypical fibroxanthoma (KAF) has recently been categorized as a variant of atypical fibroxanthoma. This paper will emphasize the importance of including KAF in both clinical and histological differential diagnosis of benign and malignant lesions which exhibit keloidal collagen and will also review the current literature on epidemiology, pathogenesis, histology, immunochemistry and treatments.

Clear cell atypical fibroxanthoma: a case report and review of the literature

Atypical fibroxanthoma (AFX) is a group of cutaneous tumors characterized by a population of fusiform, epithelioid and pleomorphic cells. Clinically, AFX is commonly found on the head and neck of older adults as a solitary ulcerated nodule. Clear cell atypical fibroxanthoma is a very rare variant of AFX, with only 13 cases reported to date. The differential diagnoses often include dermal neoplasms composed of clear cells, such as squamous cell carcinoma, basal cell carcinoma, metastatic renal cell carcinoma and balloon cell malignant melanoma. These diagnoses can be ruled out by the typical immunohistochemical profile of clear cell AFX, which is negative for specific epithelial and melanocytic markers. Herein, we describe a rare and unusual case of clear cell AFX arising on the ear of a relatively young adult patient. Histologically, the dermis was completely replaced by an atypical population of vacuolated cells with numerous atypical mitoses. Immunohistochemical stains were negative forpancytokeratin, CK5/6, CK7, and p63 S100 and Melan-A stains. CD10 and CD68 stains were positive, making the findings consistent with the diagnosis of clear cell atypical fibroxanthoma.

Advances in the clinicopathological and molecular classification of cutaneous mesenchymal neoplasms

In recent years, there have been several important refinements in the classification of cutaneous mesenchymal neoplasms, including the description of new tumour types, along with the identification of novel and recurrent molecular genetic findings. In addition to providing new insights into tumour biology, many of these advances have had significant clinical consequences with regard to diagnostics, management, and prognostication. Newly described entities include pseudomyogenic haemangioendothelioma, haemosiderotic fibrolipomatous tumour, and fibroblastic connective tissue naevus, which are reviewed in the context of the principal differential diagnoses and significant clinical implications. Genetic characterization of several soft tissue tumour types that occur in the skin has resulted in the identification of diagnostically useful markers: ALK gene rearrangement with corresponding ALK protein expression by immunohistochemistry in epithelioid fibrous histiocytoma; the WWTR1-CAMTA1 fusion gene with CAMTA1 protein expression in epithelioid haemangioendothelioma; MYC amplification and overexpression in radiation-associated angiosarcoma; and EWSR1 gene rearrangement in cutaneous myoepithelial tumours. Finally, the classification of intradermal smooth muscle tumours and unclassified/pleomorphic dermal sarcoma has been refined, resulting in both improved classification and improved prognostication. Many of the tumour types listed above are encountered not only by specialist dermatopathologists, but also by practising general surgical pathologists, and this review should therefore provide a widely applicable update on the histological and molecular classification of cutaneous mesenchymal neoplasms, along with the appropriate use of ancillary diagnostic tests, in particular immunohistochemistry, in the evaluation of such lesions and their histological mimics.

Pleomorphic dermal sarcoma: a more aggressive neoplasm than previously estimated

BACKGROUND

Pleomorphic dermal sarcoma (PDS) is a rare neoplasm sharing pathological features with atypical fibroxanthoma, but adding tumor necrosis, invasion beyond superficial subcutis or vascular or perineural infiltration. Although its metastatic risk has been estimated to be less than 5%, its real outcome is presently uncertain because of its rarity and to the lack of homogeneous criteria used in reported cases.

METHODS

Retrospective clinicopathological study of 18 cases of PDS.

RESULTS

The lesions presented as tumors or plaques (size: 7-70 mm) on the head of elderly patients (median: 81 years), without a gender predominance. Histopathologically, they consisted of spindle cells arranged in a fascicular pattern, containing pleomorphic epithelioid and giant multinucleated cells in varying proportions, and usually exhibiting numerous mitotic figures and infiltrative tumor margins. No immunoexpression for cytokeratins, S100 protein, desmin or CD34 was observed. Necrosis and venous invasion were found in three tumors each (17%). Follow-up was available in 15 cases (median: 33 months). Three patients (20%) had local recurrences, all with incomplete primary surgical resections. Three patients (20%) developed distant metastases in the skin, regional lymph nodes and/or lungs and died from the disease.

CONCLUSION

Our data suggest that PDS may be a more aggressive neoplasm than previously estimated.

Atypical fibroxanthoma: new insights

Atypical fibroxanthoma (AFX) is an ultraviolet radiation-associated dermal neoplasm. To address the clinicopathologic and molecular features of this particular neoplasm. The author conducted a literature review using PubMed searching for articles relating to AFX. AFX usually appears as a rapidly growing nodular or nodulo-ulcerative lesion. It occurs on sun-exposed skin of elderly peoples. AFX may be composed predominantly of pleomorphic, spindle, epithelioid cells, or admixture of these cells. The differential diagnosis of AFX includes pleomorphic dermal sarcoma, squamous cell carcinoma, malignant melanoma and leiomyosarcoma. Several observations favor a mesenchymal origin for AFX. These reviews address the clinicopathologic features, molecular pathology, prognosis and treatment of this neoplasm.

Current status of surgery in dermatology

An article titled "Current issues in dermatologic office-based surgery" was published in the JAAD in October 1999 (volume 41, issue 4, pp. 624-634). The article was developed by the Joint American Academy of Dermatology/American Society for Dermatologic Surgery Liaison Committee. A number of subjects were addressed in the article including surgical training program requirements for dermatology residents and selected advances in dermatologic surgery that had been pioneered by dermatologists. The article concluded with sections on credentialing, privileging, and accreditation of office-based surgical facilities. Much has changed since 1999, including more stringent requirements for surgical training during dermatology residency, and the establishment of 57 accredited Procedural Dermatology Fellowship Training Programs. All of these changes have been overseen and approved by the Residency Review Committee for Dermatology and the Accreditation Committee for Graduate Medical Education. The fertile academic environment of academic training programs with interaction between established dermatologic surgeons and fellows, as well as the inquisitive nature of many of our colleagues, has led to the numerous major advances in dermatologic surgery, which are described herein.

Atypical fibroxanthoma with pseudoangiomatous features: a histological and immunohistochemical mimic of cutaneous angiosarcoma

Atypical fibroxanthoma and pleomorphic dermal sarcoma may be difficult to separate from cutaneous angiosarcoma. We aim to study the morphological spectrum of pseudoangiomatous features in these tumors and the value of staining for endothelial markers CD31, CD34, FLI1, and ERG. Eleven atypical fibroxanthomas and 3 pleomorphic dermal sarcomas were identified. All tumors arose on sun-damaged skin of elderly men. Atypical fibroxanthomas were nodular and confined to the dermis, whereas pleomorphic dermal sarcoma invaded into underlying fascia. All tumors were composed of pleomorphic epithelioid and spindle cells showing blood-filled spaces and intratumoral hemorrhage. Intracytoplasmic vacuoles (n = 4), hemosiderin deposition (n = 2), and keloidal stromal change (n = 1) were also noted. Immunohistochemically, CD31 was expressed in 43% of cases, FLI1 in 79% and smooth muscle actin in 50%. Staining for CD34, ERG, S100, HMB-45, desmin, p63 and cytokeratins was negative. Follow up (median, 43.1 months; range 1-100), available for 10 patients, showed no adverse outcome. Pseudoangiomatous features and aberrant expression of CD31 and FLI1 in atypical fibroxanthoma and pleomorphic dermal sarcoma may lead to an erroneous diagnosis of cutaneous angiosarcoma. Negativity for CD34 and ERG, in particular, is a reliable differentiating feature in this setting.

Nonmelanoma skin cancer

Nonmelanoma skin cancer (NMSC) is the most common form of malignancy in humans. The incidence of NMSC continues to increase despite increased awareness and sun-protective measures. If neglected or mismanaged, NMSC can cause significant morbidity and even death. The most common forms of NMSC on the head and neck include basal cell carcinoma, squamous cell carcinoma, sebaceous carcinoma, eccrine porocarcinoma, Merkel cell carcinoma, atypical fibroxanthoma, and microcystic adnexal carcinoma. Surgery is the mainstay of treatment (standard excision, Mohs micrographic surgery, curettage); however, other modalities exist, including radiation, topical immunomodulators, photodynamic therapy, and new systemic medications.

A case of atypical fibroxanthoma of subungual type: ultrasound and magnetic resonance imaging findings

Subungual atypical fibroxanthoma is a rare mesenchymal skin tumor of intermediate malignancy. It classically presents as a relatively nondescript, erythematous nodule; it may ulcerate and bleed, but pain and pruritus are uncommon. In the differential diagnoses of subungual tumors, glomus tumor, soft tissue chondroma, keratoacanthoma, hemangioma, lobular capillary hemangioma, epidermal and mucoid cysts, squamous cell carcinoma, and malignant melanoma have been suggested. But atypical fibroxanthoma has not been included in the differential diagnoses. We report a case that occurred in a 56-year-old man with subungual atypical fibroxanthoma mimicking malignant soft tissue tumor in the right fifth toe.