Management of pleomorphic dermal sarcoma

The incidence of atypical fibroxanthoma and pleomorphic dermal sarcoma in Denmark from 2002 to 2022

BACKGROUND

The purpose of this study was to assess trends in the incidence rates and overall survival of atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) in the Danish population from 2002 to 2022.

METHODS

We included all patients diagnosed with AFX or PDS in the Danish National Pathology Register (DNPR) during the study period. We computed the age-adjusted incidence rate (AAIR) per 100,000 and the average annual percent change (AAPC) and developed an age-period-cohort (APC) model of incidence.

RESULTS

We included a total of 1118 patients, 78.3 % of whom were men. The median age upon diagnosis for AFX and PDS was 77.6 and 78.4 years, respectively. 84.5 % of the 1118 patients received an AFX diagnosis, while 15.5 % received a PDS diagnosis. The AAIR rose from 0.2 per 100,000 individuals in 2002 to 0.5 per 100,000 by 2022, with a peak increase of 0.75 per 100,000 in 2014. The AAPC for both tumors was 5.3 (95 % CI 2.9 %-7.7 %). We found a significant difference in overall survival between AFX and PDS, with PDS having worse overall survival than AFX.

CONCLUSION

This study, which included the largest non-selected national population to date, found a significant increase in the incidence of AFX and PDS between 2002 and 2015, followed by a decrease.

Histopathologic Evaluation of Atypical Fibroxanthoma or Pleomorphic Dermal Sarcoma Debulk Specimen from Mohs Surgery: A Requirement for Their Proper Distinction

Pleomorphic dermal sarcomas can be clinically aggressive, with a higher tendency to cause local recurrence, metastasis, and death. Atypical fibroxanthoma and pleomorphic dermal sarcoma are histopathologically similar, and their distinction requires a systematic examination of the entire excised tumor. Since Mohs micrographic surgery is commonly utilized to treat atypical fibroxanthoma, a histopathologic evaluation of debulk specimens by permanent pathology is prudent to avoid underdiagnosing pleomorphic dermal sarcoma. This approach can improve risk assessment and treatment decisions, ultimately enhancing patient outcomes. Also, the proper distinction will facilitate the future development of accurate staging criteria and additional treatment modalities.

Pleomorphic Dermal Sarcoma

Pleomorphic dermal sarcoma (PDS) is a rare cutaneous/subcutaneous neoplasm of purported mesenchymal differentiation that exists along a clinicopathologic spectrum with atypical fibroxanthoma (AFX). While PDS and AFX share histopathologic and immunohistochemical features, PDS exhibits deeper tissue invasion and has a higher rate of metastasis and local recurrence than AFX. Given its aggressive clinical course, early recognition and clinical management of PDS are essential for optimizing patient outcomes. This review aims to provide a brief overview of the clinicopathologic and molecular features, prognosis, and treatment of PDS.

Pleomorphic dermal sarcoma of the scalp - A single-centre experience

BACKGROUND

Pleomorphic dermal sarcoma (PDS) of the scalp is a rare tumour which is usually slow growing, but occasionally displays rapid growth and has a low rate of local recurrence. Surgical resection is the mainstay of treatment, with or without radiotherapy. The aim of this study is to describe the surgical approach and the additional benefit of radiotherapy to the treatment of these patients.

METHODS

Retrospective, single-centre analysis of patients with PDS of the scalp that underwent surgical resection between 2007 and 2021 (n = 24). Treatment variables including depth of resection (superficial or deep to the galea aponeurotica) and adjuvant radiotherapy were investigated.

RESULTS

Twenty-four patients were included in this study. Median age was 80 (range, 52-95), with a median ASA score of 3 (2-3). Sixteen (66.6 %) patients underwent surgical resection including the galea, while the rest (n = 8) did not or was not known. Radiotherapy was given in 7 (29 %) patients in which only 3 (12.5 %) were in the galeal resection group. Reasons for radiotherapy administration were concomitant SCC found at the same area of resection and close margins. In a median follow-up of was 26.2 months (range, 13.6-102.5) there was only one recurrence event.

CONCLUSIONS

PDS of the scalp can be safely managed with a surgical resection if clear surgical margins are achieved without radiotherapy with good oncological outcomes.

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: it might be rare but it exists

Pleomorphic dermal sarcoma (PDS) is a rare mesenchymal tissue tumor. Its differential diagnosis from similar tumors, such as low differentiated squamous cell carcinoma, fibrosarcoma, desmoplastic melanoma, atypical fibroxanthoma (AFX), may be difficult, as they have similar clinical and histological presentation. We present a case of an 83-year-old man exhibiting an exophytic scalp lesion. Excision of the lesion was performed, ensuring clear surgical margins and pathologic examination revealed an invasive pleomorphic dermal sarcoma. This case highlights a rare case of a large pleomorphic dermal sarcoma, and it discusses the histological, molecular features, its differential diagnosis and management of PDS.

[Micrographic controlled surgery in everyday dermatosurgery]

Micrographic controlled surgery (MCS) has become established in dermatosurgery in recent years and includes various methods to enable the histologically proven complete resection of malignant cutaneous tumors, while at the same time sparing tumor-free tissue in the immediate vicinity as much as possible. MCS is of great importance in the surgical treatment of cutaneous malignancies in so-called problem locations and aggressive tumor subtypes. Indications for MCS include basal cell carcinoma, cutaneous squamous cell carcinoma, Bowen's disease and Bowen's carcinoma, melanoma in chronic light-damaged skin with acral lentiginous melanoma, dermatofibrosarcoma protuberans (DFSP), and Merkel cell carcinoma. However, other tumor entities are also treated using MCS, such as extramammary Paget's disease and various cutaneous sarcomas. All procedures subsumed under MCS have in common the marking of the surgical specimen for topographical orientation, which provides assignment of remaining tumor remnants. Various methods of MCS (3D histology, the horizontal method or Mohs surgery) are presented in this article. Furthermore, this article aims to raise awareness of the possibilities and limitations of micrographically controlled surgery.

Survival differences of low-grade versus high-grade head and neck pleomorphic dermal sarcomas and a review of a scalp case

Objective

To examine survival by tumor grade of pleomorphic dermal sarcomas (PDS) of the head and neck (H&N) and review a scalp PDS case.

Methods

Patients in the Surveillance, Epidemiology, and End Results (SEER) database were included from 1980 to 2016 based on a diagnosis of H&N PDS. Survival estimates were performed using Kaplan-Meier analysis. Additionally, a case of a grade III H&N PDS is presented.

Results

Two hundred-seventy cases of PDS were identified. The mean age at diagnosis was 75.1 years (SD: 13.5). Two hundred-thirty-four (86.7%) patients were male. Eighty-seven percent of patients received surgery as a part of their care. The 5-year overall survival rates for grades I, II, III, and IV PDSs were 69%, 60%, 50%, and 42%, respectively (P = 0.03).

Conclusions

H&N PDS occurs most commonly in older-age males. Surgical management is frequently a part of H&N PDS care. Survival rates significantly decline based on tumor grade.

Immune checkpoint inhibitors for unresectable or metastatic pleomorphic dermal sarcomas

Pleomorphic dermal sarcomas (PDS) are rare neoplasms of the skin that occur in UV-exposed sites in the elderly, but represent the most common cutaneous sarcomas. Although the majority of PDS can be surgically removed, local recurrences occur in up to 28%, usually occurring within the first two years after primary excision. Metastases are diagnosed in up to 20% of cases, mainly observed in the skin, lymph nodes and lungs, preferentially affecting patients with underlying hemato-oncologic diseases. Similar to other UV-induced tumors, PDS are inflammatory and immunogenic tumors (with a high number of CD4+/CD8+ tumor-infiltrating lymphocytes (TILs) and checkpoint molecule expression such as PD-L1, LAG-3, TIGIT) with a very high mutational burden. The most common genetic alterations include UV-induced TP53 loss of function mutations, followed by alterations in the CDKN2A/B gene. Rarely, targetable genetic alterations can be detected. Compelling experimental data and clinical reports about PD-1/PD-L1-blocking antibodies in patients with PDS suggest its use as first line treatment in unresectable or metastatic tumor stages. However, individual ("off-line") patient management should be discussed in an interdisciplinary tumor board based on molecular genetic testing, mutational burden, PD-L1 expression, and evidence of tumor-infiltrating lymphocytes in addition to comorbities of the individual patient.

Oncological Safety and Recurrence in the Surgical Treatment of Atypical Fibroxanthoma and Pleomorphic Dermal Sarcoma of the Scalp

Simple Summary

Atypical fibroxanthoma and pleomorphic dermal sarcoma represent two tumors on the spectrum of a rare dermal sarcoma entity. Close clinical presentation and nearly identical histologic features but distinct prognoses make proper treatment strategies challenging. We performed a retrospective analysis of 32 patients with AFX or PDS in the scalp to provide guidance regarding the extent of radical excision to achieve stable oncological outcomes and whether radical tumor resection on the scalps required complex soft-tissue reconstruction. Compared to AFX, PDS shows a more aggressive growth pattern with frequent satellite metastases and distant metastases. These require extensive resections for local control to achieve long-term remission in most PDS patients. Despite the limited elasticity of the scalp, plastic reconstructive procedures can obtain reliable soft tissue reconstruction, even for complete scalp defects. Due to their rarity, managing these tumors requires an interdisciplinary setting in a specialized sarcoma center.

Abstract

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are two distinct designations for a rare dermal sarcoma entity. These tumors arise predominantly in the sun-damaged skin of elderly patients. Although both AFX and PDS have a similar clinical presentation and nearly identical genetic features, they significantly differ in prognosis. Here we present a retrospective single-center chart review analyzing the outcomes of patients treated for dermal sarcoma. The radicality of the tumor-resection extent and soft-tissue reconstructive options were assessed. Patients between January 2010 and August 2021 were included. We recorded resection margins, tumor recurrence, overall survival, number of operations until complete tumor resection, and reconstructive procedures; any complications were recorded. Furthermore, we analyzed a subgroup of patients with satellite metastases. A total of 32 patients met the inclusion criteria (30 male, 2 female, median age of 77.5 years (interquartile range (IQR) 74–81)). Histopathology revealed AFX in 14 patients and PDS in 18 patients. Margin-free resection was achieved in 31 cases, and 27 patients were remission free over the reported period. The local recurrence rate was 5, and distant metastasis was detected in four cases. Of all the PDS cases, nine presented with satellite metastasis. No AFX had satellite metastases. Due to their rarity, managing these tumors requires an interdisciplinary setting in a specialized sarcoma center.

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.

Pleomorphic dermal sarcoma: Clinicopathological features and outcomes from a 5-year tertiary referral centre experience

BACKGROUND

Pleomorphic dermal sarcoma (PDS) describes rare dermal-based malignant tumours that are morphologically similar to atypical fibroxanthoma (AFX). PDS may be differentiated from AFX by the presence of one or more of the following histologic features: subcutaneous invasion, tumour necrosis, lymphovascular invasion (LVI), and/or perineural infiltration (PNI).

AIMS

To further define the clinicopathological features, surgical management, and outcomes of PDS primary tumours.

METHODS AND RESULTS

This study was a retrospective observational case series using a database search from 2012 to 2017. Inclusion criteria required all cases to meet the histopathologic criteria for PDS as confirmed by a specialist soft-tissue histopathologist. A total of n = 17 cases were included with a median age of 78 years (range 66-85). All tumours were located on the head and neck, with 13/17 located on the scalp. Primary treatment was with wide local excision (WLE) in all cases. Median follow-up was 48 months. Local recurrence occurred in 4/17 cases (24%) and distant metastasis in 2/17 cases (12%).

CONCLUSION

PDS behaves more aggressively than atypical fibroxanthoma with which it shares a biologic continuum. The optimal surgical management approach is yet to be determined.

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.

Relation Between Atypical Fibroxanthoma and Pleomorphic Dermal Sarcoma: Histopathologic Features and Review of the Literature

The relation between atypical fibroxanthoma and pleomorphic dermal sarcoma has led to confusion and debate in the literature. Both tumors present on sun-exposed skin, typically on the head and neck, in patients of advanced age. Both are comprised of a variable mix of histiocytoid, spindle, epithelioid, and/or giant multinucleated cells with pleomorphic nuclei. No immunohistochemical diagnostic techniques have emerged to distinguish these tumors. Diagnosis is by exclusion. Histologically, atypical fibroxanthoma is seen as a well-circumscribed dermal nodule but there will be no evidence of extensive subcutaneous invasion, tumor necrosis, or lymphovascular or perineural invasion. Therefore, if any of the aforementioned features is present, the diagnosis would be pleomorphic dermal sarcoma. This narrative review of the literature aims to identify the distinguishing and overlapping histopathologic features of these 2 tumors as they have been described in case series.