Clinical spectrum of atypical fibroxanthoma and undifferentiated pleomorphic sarcoma in solid organ transplant recipients: a collective experience

Current research and management of undifferentiated pleomorphic sarcoma/myofibrosarcoma

Undifferentiated pleomorphic sarcoma (UPS), once termed as malignant fibrous histiocytoma, has always been diagnosed exclusively in clinical practice because it lacks any defined resemblance to normal mesenchymal tissue. Although myxofibrosarcoma (MFS) has been separated from UPS due to its fibroblastic differentiation with myxoid stroma, UPS and MFS are still identified as a sarcoma group in terms of molecular landscapes. In this review article, we will describe the associated genes and signaling pathways involved in the process of sarcoma genesis and make a summary of conventional management, targeted therapy, immunotherapy, and some novel potential treatments of UPS/MFS. With the progressive advancements in medical technology and a better understanding about the pathogenic mechanism of UPS/MFS in the coming decades, new lights will be shed on the successful management of UPS/MFS.

Lethal Dermal Sarcoma in Immunosuppressed Patients

Skin cancer is the leading malignancy in immunosuppressed patients, including organ transplant recipients (OTRs), which is increasing in incidence as OTRs live longer. We performed a single-center case series of 4 patients with scalp pleomorphic dermal sarcoma and a history of multiple keratinocyte carcinomas. Outcomes included incidence of dermal sarcoma, dermal sarcoma-related mortality, and histopathologic findings. Out of more than 200 patients followed over a 3-year period in Massachusetts General Hospital High Risk Skin Cancer Clinics, all skin cancer-related deaths (2/2) were due to metastatic dermal sarcoma. Three of 4 patients diagnosed with scalp dermal sarcoma were OTRs and had been on at least one immunosuppressive medication for a median of 9 years. For patients who died from dermal sarcoma, the median time between diagnosis and death was 6 months. Our findings suggest pleomorphic dermal sarcoma contributes to skin cancer-related morbidity and mortality in OTRs.

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.

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.

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.

Multifocal pleomorphic dermal sarcoma and the role of inflammation and immunosuppression in a lung transplant patient: a case report

Background

Pleomorphic dermal sarcoma is the cutaneous variant of undifferentiated pleomorphic sarcoma. It is a rare malignancy of unclear histogenesis; it is a diagnosis of exclusion that requires extensive use of immunohistochemistry to rule out other malignancies. Pleomorphic dermal sarcoma typically presents as a solitary tumor in sun-exposed areas and may have unpredictable clinical behavior, with some tumors associated with metastasis and death.

Case presentation

We present an unusual case of multifocal pleomorphic dermal sarcoma arising in the areas of alpha-1-antitrypsin deficiency panniculitis in a lung transplant patient. Our patient was a 58-year-old white woman whose initial presentation was consistent with alpha-1-antitrypsin deficiency panniculitis. She then developed extensive multifocal, bleeding, and ulcerated nodules in the areas of the panniculitis. A skin biopsy was consistent with a diagnosis of pleomorphic dermal sarcoma. Her immunosuppressive regimen was decreased, and she was treated with liposomal doxorubicin 40 mg/m² every 3 weeks with some initial improvement in the size of her tumors. However, soon after beginning therapy, she developed pneumonia and septic shock and ultimately died from multi-organ failure.

Conclusions

We hypothesize that chronic, multifocal inflammation in the skin in the setting of immunosuppression led to simultaneous, malignant transformation in numerous skin lesions. We discuss the challenges of diagnosing pleomorphic dermal sarcoma, therapeutic options, and stress the need for multidisciplinary management of these cases.

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.

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.

Atypical fibroxanthoma and pleomorphic dermal sarcoma harbor frequent NOTCH1/2 and FAT1 mutations and similar DNA copy number alteration profiles

Atypical fibroxanthomas and pleomorphic dermal sarcomas are tumors arising in sun-damaged skin of elderly patients. They have differing prognoses and are currently distinguished using histological criteria, such as invasion of deeper tissue structures, necrosis and lymphovascular or perineural invasion. To investigate the as-yet poorly understood genetics of these tumors, 41 atypical fibroxanthomas and 40 pleomorphic dermal sarcomas were subjected to targeted next-generation sequencing approaches as well as DNA copy number analysis by comparative genomic hybridization. In an analysis of the entire coding region of 341 oncogenes and tumor suppressor genes in 13 atypical fibroxanthomas using an established hybridization-based next-generation sequencing approach, we found that these tumors harbor a large number of mutations. Gene alterations were identified in more than half of the analyzed samples in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter. The presence of these alterations was verified in 26 atypical fibroxanthoma and 35 pleomorphic dermal sarcoma samples by targeted amplicon-based next-generation sequencing. Similar mutation profiles in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter were identified in both atypical fibroxanthoma and pleomorphic dermal sarcoma. Activating RAS mutations (G12 and G13) identified in 3 pleomorphic dermal sarcoma were not found in atypical fibroxanthoma. Comprehensive DNA copy number analysis demonstrated a wide array of different copy number gains and losses, with similar profiles in atypical fibroxanthoma and pleomorphic dermal sarcoma. In summary, atypical fibroxanthoma and pleomorphic dermal sarcoma are highly mutated tumors with recurrent mutations in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter, and a range of DNA copy number alterations. These findings suggest that atypical fibroxanthomas and pleomorphic dermal sarcomas are genetically related, potentially representing two ends of a common tumor spectrum and distinguishing these entities is at present still best performed using histological criteria.

Skin Cancers in Organ Transplant Recipients

Long-term utilization of immunosuppression in organ transplant recipients (OTRs) leads to decreased immune-mediated tumor surveillance and development of malignant tumors. A delicate balance needs to be maintained in the intensity of immunosuppression to keep the risk of malignancy low without jeopardizing life-saving graft function. OTRs are prone to developing skin cancers that exhibit unique epidemiologic, pathophysiologic, and prognostic characteristics. In this review, we discuss the most commonly reported skin cancers in OTRs: squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Kaposi sarcoma, Merkel cell carcinoma, and malignant melanoma (MM). Tumors in this high-risk population are aggressive and may respond poorly to standard therapies; however, new targeted therapies are promising. Checkpoint inhibitor antibodies have been used for treatment of cutaneous SCC, Merkel cell carcinoma, and MM; epidermal growth factor receptor inhibitors have been used for cutaneous SCC; hedgehog pathway inhibitors have been used for BCC; and BRAF and MEK inhibitors are being used increasingly in the management of MM. Guidelines for dermatologic screening are variable and primarily based on expert opinion. Prospective evidence-based trials by multidisciplinary groups are needed to better define surveillance schedules for pre- and posttransplant cutaneous malignancies.

Risk of Second Malignancies in Solid Organ Transplant Recipients Who Develop Keratinocyte Cancers

Solid organ transplant recipients have increased risk for developing keratinocyte cancers, including cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), in part as a result of immunosuppressive medications administered to prevent graft rejection. In the general population, keratinocyte cancers are associated with increased risks of subsequent malignancy, however, the risk in organ transplant populations has not been evaluated. We addressed this question by linking the U.S. Scientific Registry of Transplant Recipients, which includes data on keratinocyte cancer occurrence, with 15 state cancer registries. Risk of developing malignancies after keratinocyte cancer was assessed among 118,440 Caucasian solid organ transplant recipients using multivariate Cox regression models. Cutaneous SCC occurrence (n = 6,169) was associated with 1.44-fold increased risk [95% confidence interval (CI), 1.31-1.59] for developing later malignancies. Risks were particularly elevated for non-cutaneous SCC, including those of the oral cavity/pharynx (HR, 5.60; 95% CI, 4.18-7.50) and lung (HR, 1.66; 95% CI, 1.16-2.31). Cutaneous SCC was also associated with increased risk of human papillomavirus-related cancers, including anal cancer (HR, 2.77; 95% CI, 1.29-5.96) and female genital cancers (HR, 3.43; 95% CI, 1.44-8.19). In contrast, BCC (n = 3,669) was not associated with overall risk of later malignancy (HR, 0.98; 95% CI, 0.87-1.12), including any SCC. Our results suggest that transplant recipients with cutaneous SCC, but not BCC, have an increased risk of developing other SCC. These findings somewhat differ from those for the general population and suggest a shared etiology for cutaneous SCC and other SCC in the setting of immunosuppression. Cutaneous SCC occurrence after transplantation could serve as a marker for elevated malignancy risk. Cancer Res; 77(15); 4196-203. ©2017 AACR.

LN2, CD10, and Ezrin Do Not Distinguish Between Atypical Fibroxanthoma and Undifferentiated Pleomorphic Sarcoma or Predict Clinical Outcome

BACKGROUND

Atypical fibroxanthoma (AFX) is a rare cutaneous spindled cell neoplasm. For both diagnostic and therapeutic purposes, it is important to distinguish AFX from other poorly differentiated tumors, including undifferentiated pleomorphic sarcoma (UPS).

OBJECTIVE

The authors aimed to identify the clinical, histologic, and immunohistochemical expression of LN2, ezrin, and CD10 in AFX and UPS tumors.

METHODS AND MATERIALS

The authors retrospectively examined the charts of patients with AFX and UPS treated with Mohs micrographic surgery (MMS) at 2 academic institutions. Patient demographics, tumor characteristics, and clinical course data were collected. Immunohistochemical stains were performed on primary and recurrent AFX and UPS tumors with monoclonal antibodies against the B-cell marker LN2 (CD74), CD10, and ezrin.

RESULTS

In the series of 169 patients with AFX included in this study, local recurrence was rare at 3%. In contrast, the seven patients with UPS had an aggressive clinical course with 1 local recurrence and 2 distant metastases. Immunohistochemistry staining for ezrin, LN2, and CD10 were similar in AFX and UPS tumors.

CONCLUSION

AFX can be treated with MMS with rare instances of recurrence. Undifferentiated pleomorphic sarcoma has a more aggressive clinical course with increased risk for recurrence and metastasis. Staining with ezrin, LN2, and CD10 did not differentiate AFX or UPS tumors.

TERT promoter mutations are frequent in atypical fibroxanthomas and pleomorphic dermal sarcomas

Activating mutations in the TERT promoter leading to increased telomerase expression were recently identified in cutaneous melanoma and subsequently in many other types of cancer. These mutations lead to increased telomerase expression, allowing cells to proliferate continuously without entering apoptosis or senescence. Atypical fibroxanthomas and pleomorphic dermal sarcomas are genetically poorly understood tumors developing in the skin of older patients. Known genetic events in these tumors are mutations in TP53 (atypical fibroxanthoma and pleomorphic dermal sarcoma) and RAS (pleomorphic dermal sarcoma) genes, often having a UV signature. We analyzed a cohort of 27 atypical fibroxanthomas and 34 pleomorphic dermal sarcomas for the presence of TERT promoter mutations by conventional Sanger sequencing. TERT promoter mutations were identified in 25 (93%) atypical fibroxanthomas and in 26 (76%) pleomorphic dermal sarcomas. Mutations were found to have a UV signature (C>T or CC>TT) and were largely identical to those detected in cutaneous melanoma. Our data show that TERT promoter mutations are the most frequent mutations in atypical fibroxanthomas and pleomorphic dermal sarcomas reported to date. The identified mutations confirm the pathogenetic role of UV exposure in both atypical fibroxanthomas and pleomorphic dermal sarcomas and suggest that telomere maintenance through increased expression of telomerase plays an important role in the pathogenesis of these tumors.

Atypical fibroxanthoma

Atypical fibroxanthoma (AFX) is a rare neoplastic disease of the skin. Since the term was coined in the early 1960s, the disease has been viewed in many ways. For a long time AFX was regarded as a superficial variant of malignant fibrous histiocytoma (MFH). When the concept of MFH was re-evaluated and the term "undifferentiated pleomorphic sarcoma" (UPS) introduced, the controversy about the nature of AFX increased. The following review aims at providing an understanding of the present status of diagnosis and therapy of AFX based on the historical context and current data.