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

[Atypical fibroxanthoma]

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

Undifferentiated pleomorphic sarcoma of the lateral thigh with KRAS/NF1 co-mutation recurred after repetitive surgical resection: A case report and review of the literature

Undifferentiated pleomorphic sarcoma (UPS), a rare soft tissue sarcoma subtype, mainly occurs in the deep parts of the limbs and trunk, observed as rapidly growing painless lumps, rarely located under the skin or protrudes from the skin surface. The risk of recurrence and metastasis is associated with multiple factors. Mutation of tumor gene, tumor occurrence, location and depth of invasion, and tumor size have great influence on prognosis. In this study, we described a case of UPS with KRAS/NF1 co-mutation. This case had undergone UPS extended resection for four times combined with chemotherapy in another hospital. The resection area was more than 3 cm, and tumor relapsed after all operations. This time, the tumor protruded from the left lateral surface with ulceration and infection. Due to multiple surgeries, the anatomy of the lateral femoral vessels has been seriously damaged. We performed expanded tumor resection and adjacent flap transfer repair; meanwhile, vacuum sealing drainage (VSD)-negative pressure closed the drainage, and the patient recovered well after surgery. After surgery, the patient was transferred to the Department of Oncology for chemotherapy. There was no recurrence after 6 months of follow-up. Gene mutation plays an important role in UPS recurrence and metastasis. At the same time, occurrence and location, depth, and size of UPS have great influence on the prognosis. Deeper exploration and expanded resection are important for the prognosis of UPS.

An extremely scarce incidence of primary Undifferentiated Pleomorphic Sarcoma of the Scalp of a 52-year-old female - A Case Report

Introduction and importance

Sarcomas are malignant mesenchymal-cell tumors that comprise 1 % of all adult tumors. Undifferentiated Pleomorphic Sarcoma comprises a vastly rare subtype. It mostly occurs in males in their 6th decade of life. However, their exact incidence remains poorly demarcated, especially those occurring in the scalp. Since they lack any disease-specific presentations, we should maintain high clinical suspicion when presented with similar cases.

Case presentation

Herein, we demonstrate the clinical case of a 52-year-old Middle Eastern female, who presented to the outpatient clinic complaining of a one-year history of progressively growing protuberance in her right side of the scalp. It was painful and rapidly increased in size. Presurgical radiological assessment suspected a cystic formation. Utter resection of the mass was achieved, and histopathological analysis diagnosed it as a primary Undifferentiated Pleomorphic Sarcoma.

Clinical discussion

Meticulous surgical resection was the cornerstone treatment of our patient. Radiological imaging in addition to clinical suspicion was utilized for preoperative assessment. This patient has had a successful post-surgical recovery. She has been surveilled for 6 months so far with no evidence of tumor recurrence, metastasis, or clinical complications.

Conclusion

It is especially rare to see a primary Undifferentiated Pleomorphic Sarcoma in any patient population. It's even rarer that it occurs in such a patient demographic. Hence, it's vital that we document cases of this rare malignancy because that would lead the way in conducting informative clinical studies which enable physicians to select the proper treatment modality.

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Sarcomas are malignant mesenchymal-cell tumors that comprise 1 % of all adult tumors.

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Undifferentiated Pleomorphic Sarcoma comprises a rare subtype. It mostly occurs in males in their 6th decade.

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UPS showed higher tendencies to occur in males rather than females and favored the White rather than African race.

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To establish a final diagnosis relies on competent histopathological and immunohistochemical analysis.

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The ideal management of UPS occurring in the head and neck is utter surgical resection with free margins of 2 cm.

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 Demonstrating HMB45+ Staining

ABSTRACT

Immunohistochemistry is useful and often necessary for the diagnosis of many histopathological entities, including atypical fibroxanthoma (AFX), which is typically considered a diagnosis of exclusion after ruling out spindle cell melanoma, sarcomatoid carcinoma, and other spindle cell tumors. AFX is a superficial fibrohistiocytic tumor previously believed to be related to pleomorphic sarcoma (formerly known as malignant fibrous histiocytoma), but is now considered a distinct clinicopathological entity. AFXs commonly express CD68, smooth muscle actin, and lysozyme and are usually negative for melanocytic markers such as HMB45 and S100. However, immunohistochemistry can sometimes be misleading, especially when used without other relevant markers in making a histopathologic diagnosis. HMB45 is a glycoprotein marker of premelanosomes and is often helpful in identifying melanoma because it stains melanosomes in the epidermis, dermis, and nevi glycocomplexes. We report a case of AFX which was strongly positive for HMB45, but negative for all other melanocytic markers. This case emphasizes the potential pitfall of relying on a single immunohistochemical marker to make the diagnosis, especially of melanoma, and also is one of the only rare reported cases of AFXs which are HMB45+.

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

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

Leiomyosarcoma and Pleomorphic Dermal Sarcoma: Guidelines for Diagnosis and Treatment

There are 3 types of leiomyosarcoma of the skin: dermal, subcutaneous, and metastatic cutaneous. Dermal leiomyosarcoma arises from smooth muscle fibers in arrector pili muscles, genital dartos muscles, and the nipple-areola complex. It is an intermediate-grade tumor associated with a tendency for local recurrence (24%) and low metastatic potential (4%). Subcutaneous leiomyosarcoma originates from smooth muscle in blood vessel walls and has higher rates of local recurrence (37%) and metastasis (43%). Plemorphic dermal sarcoma typically affects elderly patients and arises in sun-exposed areas (e.g., the scalp). Its histologic and immunohistochemical characteristics are similar to those of atypical fibroxanthoma, but it is more aggressive (metastasis rate of 10-20%). Histologically, it can be distinguished from atypical fibroxanthoma by the observation of subcutaneous tissue invasion, perineural invasion, and foci of necrosis.

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.