Atypical fibroxanthoma: A series of 56 tumors and an unexplained uneven distribution of cases in southeast Germany

The Usefulness of Ultrasonography for Supporting the Differentiation, Diagnosis, and Treatment of Atypical Fibroxanthoma and Pleomorphic Dermal Sarcoma

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are rare histomorphological variants of a disease spectrum. After ruling out other tumor entities by immunohistochemistry, PDS can be differentiated from AFX by infiltration into the subcutis, while AFX remains confined to the dermis. The therapeutic approach is more aggressive in PDS as it can potentially metastasize. We assessed the usefulness of preoperative sonography in differentiating between the two tumor entities by identifying a potential subcutaneous infiltration. In our patients (n = 13), preoperative sonography identified and differentiated AFX and PDS with 100% accuracy and even changed the initial histological suspicion of AFX to PDS in 3 cases (23%), which was confirmed after tumor resection. Preoperative sonography of these tumors could strengthen the clinical diagnosis, avoid a delay in therapy initiation and improve patient counseling. While for AFX, micrographic-controlled surgery suffices, for PDS, resection with 2 cm safety margins and lymph node sonography to rule out lymphonodal involvement is necessary. Hence, ultrasonography can improve clinical practice by providing helpful information for dermatosurgeons, which cannot be obtained during clinical examination.

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.

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.

S1-guideline atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS)

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are rare cutaneous neoplasms representing histomorphological, genetic as well as epigenetic variants of a disease spectrum. Both tumors typically manifest as nonspecific, often ulcerated, skin- to flesh-colored nodules in chronically sun-damaged skin of elderly male patients. AFX is a rather well demarcated, often rapidly growing tumor. PDS tumors are poorly circumscribed and are characterized by aggressive infiltrative growth. Fast as well as slow growth behavior has been reported for both tumors. Histologically, both are composed of spindle-shaped and epithelioid tumor cells with pleomorphic nuclei as well as atypical multinucleated giant cells. Atypical mitoses are common. In contrast to AFX, PDS involves relevant parts of the subcutis and shows areas of tumor necrosis and/or perineural infiltration. Due to the poorly differentiated nature of AFX/PDS (Grade 3), histopathologically similar cutaneous sarcomas, undifferentiated carcinomas, melanomas and other diseases have to be excluded by immunohistochemical analysis. The treatment of choice is micrographically controlled surgery. In cases of AFX, a cure can be assumed after complete excision. Local recurrence rates are low as long as PDS tumors are surgically removed with a safety margin of 2 cm. Metastasis is rare and mostly associated with very thick or incompletely excised tumors; it mainly affects the skin and lymph nodes. Distant metastasis is even more rare. No approved and effective systemic therapy has been established.

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.

Atypisches Fibroxanthom oder pleomorphes dermales Sarkom – eine Frage der Infiltrationstiefe

Das atypische Fibroxanthom (AFX) ist eine seltene, niedrig-maligne mesenchymale Neoplasie der Haut. Die Abgrenzung zum malignen fibrösen Histiozytom bzw. pleomorphen dermalen Sarkom (PDS) wurde seit der Erstbeschreibung Anfang der 1960er-Jahre immer wieder kontrovers diskutiert. Mittlerweile wird der Begriff des pleomorphen dermalen Sarkoms für Tumore verwendet, die eine Infiltration der Subkutis, nekrotische Anteile oder eine perineurale oder lymphovaskuläre Infiltration aufweisen. Die Unterscheidung der beiden Entitäten erfolgt folglich vorwiegend histologisch, eine immunhistochemische Abgrenzung ist bisher nicht möglich.

Wir berichten über 2 Patienten mit atypischem Fibroxanthom und pleomorphem dermalem Sarkom. Beide Tumorentitäten sollten mittels weiter Exzision oder mikrografisch kontrollierter Chirurgie vollständig exzidiert werden. Insbesondere beim pleomorphen dermalen Sarkom kommt es häufiger zu Rezidiven und Metastasierung, deshalb sollte der Sicherheitsabstand größer als beim AFX gewählt werden und v. a. in den ersten 3 Jahren nach der Behandlung eine engmaschige Nachsorge erfolgen.

Eine einheitliche Klassifikation der beiden Tumorentitäten, die das aggressivere Verhalten des tiefer infiltrierenden pleomorphen dermalen Sarkoms berücksichtigt, wäre erstrebenswert.

Zudem sollten beide Tumore der Meldepflicht unterliegen, um weitere epidemiologische Daten sammeln zu können.

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.

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.

Soft Tissue Special Issue: Cutaneous Pleomorphic Spindle Cell Tumors

This manuscript provides an overview of pleomorphic spindle cell tumors presenting on sun-damaged skin of the elderly and includes discussions of atypical fibroxanthoma, pleomorphic dermal sarcoma, spindle cell and metaplastic squamous cell carcinoma, spindle cell and dedifferentiated melanoma and poorly differentiated cutaneous angiosarcoma. These tumors share many of the clinical presenting and histological features, making confident diagnosis challenging. A reliable and robust diagnosis is necessary to predict behavior as the biologic potential of these tumors ranges from benign (e.g. atypical fibroxanthoma) to outright malignant with poor survival rates (e.g. cutaneous angiosarcoma). The salient clinical, histologic and immunohistochemical characteristics are discussed in detail with emphasis on distinguishing features and differential diagnosis to provide the reader with a better understanding of these entities and helpful clues for a more robust diagnosis.

Dermal Pleomorphic Sarcoma of the Scalp - Report of Two Cases

BACKGROUND:

Neoplasias of the UV-exposed head-and-neck area of the elderly include non-melanoma skin cancers of various origin.

CASE REPORT:

We report two cases of rapid growing exophytic scalp tumors on chronic sun-damaged skin, in one case with a tendency of bleeding. The tumours were removed by wide surgical excision with 3D margin control, and the resulting defect was covered by a meshed split skin graft. Histopathologic examination disclosed a dermal pleomorphic sarcoma in both cases. The staging was unremarkable in both patients.

CONCLUSIONS:

Sarcomatous tumours of the scalp should be completely excised with a 3D margin control. Dermal pleomorphic sarcoma is a more aggressive variant compared to atypical fibroxanthoma despite some similarities.

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.

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.