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Atypical fibroxanthoma and pleomorphic dermal sarcoma are on a spectrum of cutaneous tumors that present as ulcerated lesions in older adults. We present an 84-year-old man with pleomorphic dermal sarcoma, initially presenting as a bleeding lesion of the cheek that progressed to an eroded nodule.

Undifferentiated pleomorphic sarcoma (UPS) and related tumors are the most common type of soft tissue sarcoma. However, this spectrum of tumors has different etiologies with varying rates of metastasis and survival. Two dermal-based neoplasms in this class of pleomorphic sarcomas, atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS), are challenging to differentiate at initial biopsy but vary significantly in prognosis. We performed single-cell transcriptomics on five AFX and PDS biopsy specimens as well as both single-cell and spatial transcriptomics on one PDS excision specimen to better characterize these tumors. The top differential genes between AFX and PDS were predictive of overall survival in 17 other cancers included in the Human Protein Atlas. Of these genes, COL6A3 and BGN predicted overall survival and metastasis-free survival in independent cohorts of 46 and 38 UPS tumors, respectively. COL6A3 was most predictive of overall survival in UPS patients and outperformed an established sarcoma prognostic gene panel at predicting metastasis in UPS. [ABSTRACT FROM AUTHOR]

Atypical fibroxanthoma (AFX) is a rare neoplasm, with a limited number of cases reported in the periocular region. In this case report, we detail a 63-year-old woman who presented with a polypoid, exophytic lesion on her right upper eyelid that had been progressing for a year. The lesion was meticulously excised with security margins and reconstructed using a glabellar flap. Following a thorough microscopic and immunohistochemical analysis, AFX was diagnosed. Despite its sometimes clinical and histological benign appearance, AFX is classified as a malignant neoplasm; however, it carries an excellent prognosis with low metastasis and recurrence rates. Complete excision with safety margins is essential and an adequate post-operative surveillance is recommended. Owing to its rarity, ophthalmologists should remain vigilant and include AFX in their differential diagnosis, as the tumor's benign appearance may lead to misdiagnosis of this malignant entity. [ABSTRACT FROM AUTHOR]

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.

Although extensively studied in cutaneous epithelial neoplasms, the TRPS1 immunoreactivity in cutaneous mesenchymal neoplasms and tumors of uncertain differentiation (CMNTUDs), such as atypical fibroxanthoma (AFX), remains largely unexplored. We assessed TRPS1 immunoreactivity in 135 CMNTUDs, comprising 46 fibrohistiocytic/fibroblastic tumors, 28 vascular tumors, 24 peripheral nerve sheath tumors (PNSTs), 21 tumors of uncertain differentiation, and 16 smooth muscle tumors. Additionally, we included selected cases of melanoma with spindled cell morphology or desmoplastic features (n = 9) and sarcomatoid squamous cell carcinoma (SSCC) (n = 5) to compare TRPS1 expression patterns with those of AFX. TRPS1 expression was prevalent in dermatofibromas (24/24), leiomyomas (8/8), AFXs/pleomorphic dermal sarcoma (PDS) (20/21), dermatofibrosarcomas protuberans (14/22), and leiomyosarcomas (6/8). It was uncommon in angiosarcomas (3/20), Kaposi sarcomas (2/8), and neurofibromas (5/17) and absent in perineuriomas (0/2). AFXs/PDS exhibited the highest median H-score of 240, contrasting with minimal TRPS1 immunoreactivity in vascular neoplasms and PNSTs, with median H-scores consistently below 10. Significant differences in H-score were observed between AFXs/PDS and angiosarcomas (p < 0.001), melanomas (p < 0.001), and leiomyosarcomas (p = 0.029). However, no significant difference was found compared to SSCCs, suggesting limited discriminatory power of TRPS1 in this context. This study sheds light on TRPS1 expression patterns in a subset of CMNTUDs, extending beyond prior studies primarily focused on epithelial tumors, while underscoring potential pitfalls associated with TRPS1 immunohistochemistry.

Although extensively studied in cutaneous epithelial neoplasms, the TRPS1 immunoreactivity in cutaneous mesenchymal neoplasms and tumors of uncertain differentiation (CMNTUDs), such as atypical fibroxanthoma (AFX), remains largely unexplored. We assessed TRPS1 immunoreactivity in 135 CMNTUDs, comprising 46 fibrohistiocytic/fibroblastic tumors, 28 vascular tumors, 24 peripheral nerve sheath tumors (PNSTs), 21 tumors of uncertain differentiation, and 16 smooth muscle tumors. Additionally, we included selected cases of melanoma with spindled cell morphology or desmoplastic features (n = 9) and sarcomatoid squamous cell carcinoma (SSCC) (n = 5) to compare TRPS1 expression patterns with those of AFX. TRPS1 expression was prevalent in dermatofibromas (24/24), leiomyomas (8/8), AFXs/pleomorphic dermal sarcoma (PDS) (20/21), dermatofibrosarcomas protuberans (14/22), and leiomyosarcomas (6/8). It was uncommon in angiosarcomas (3/20), Kaposi sarcomas (2/8), and neurofibromas (5/17) and absent in perineuriomas (0/2). AFXs/PDS exhibited the highest median H-score of 240, contrasting with minimal TRPS1 immunoreactivity in vascular neoplasms and PNSTs, with median H-scores consistently below 10. Significant differences in H-score were observed between AFXs/PDS and angiosarcomas (p < 0.001), melanomas (p < 0.001), and leiomyosarcomas (p = 0.029). However, no significant difference was found compared to SSCCs, suggesting limited discriminatory power of TRPS1 in this context. This study sheds light on TRPS1 expression patterns in a subset of CMNTUDs, extending beyond prior studies primarily focused on epithelial tumors, while underscoring potential pitfalls associated with TRPS1 immunohistochemistry. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Key Clinical Message: An 83‐year‐old man presented an elevated skin lesion in the left temporal area. The resected specimen was identified between a basal cell carcinoma and an atypical fibroxanthoma. A final diagnosis of basal cell carcinoma and atypical fibroxanthoma was made. This study reports a rare case of a cutaneous collision. [ABSTRACT FROM AUTHOR]

Simple Summary: While sun exposure and associated tissue changes stemming from ultraviolet radiation are closely associated with the most common forms of skin cancer, far less is known regarding rare types of skin cancer. In this study, for the first time, we used a light microscopy technique to evaluate connective tissue changes in samples from patients with six different types of rare skin cancers, assessing the relationship between these changes, patient age, and whether tumors arose on sun-exposed parts of the body. We found that these tissue changes were most pronounced for patients with specific cancers known to be linked to chronic sun damage and tumors arising on sun-exposed parts of the body. We also noted tumor type-specific trends in terms of sex ratios, sites of tumor presentation, and the relationship between the development of particular tumors and patient immunosuppression. Our results are important and novel as they expand the available data associated with these rare skin cancers while also offering insight into the value of differentiating among these tumor types based on their relationship with sun exposure, potentially informing preventative, diagnostic, and/or therapeutic approaches. (1) Background: Rare skin cancers include epithelial, neuroendocrine, and hematopoietic neoplasias as well as cutaneous sarcomas. Ultraviolet (UV) radiation and sunburns are important drivers for the incidence of certain cutaneous sarcomas; however, the pathogenetic role of UV light is less clear in rare skin cancers compared to keratinocyte cancer and melanoma. In this study, we compared the degree of actinic elastosis (AE) as a surrogate for lifetime UV exposure among selected rare skin cancers (atypical fibroxanthoma [AFX], pleomorphic dermal sarcoma [PDS], dermatofibrosarcoma protuberans [DFSP], Kaposi sarcoma [KS], Merkel cell carcinoma [MCC], and leiomyosarcoma [LMS]) while taking into account relevant clinical variables (age, sex, and body site). (2) Methods: We newly established a semi-quantitative score for the degree of AE ranging from 0 = none to 3 = total loss of elastic fibers (basophilic degeneration) and multiplied it by the perilesional vertical extent (depth), measured histometrically (tumor-associated elastosis grade (TEG)). We matched the TEG of n = 210 rare skin cancers from 210 patients with their clinical variables. (3) Results: TEG values were correlated with age and whether tumors arose on UV-exposed body sites. TEG values were significantly higher in AFX and PDS cases compared to all other analyzed rare skin cancer types. As expected, TEG values were low in DFSP and KS, while MCC cases exhibited intermediate TEG values. (4) Conclusions: High cumulative UV exposure is more strongly associated with AFX/PDS and MCC than with other rare skin cancers. These important results expand the available data associated with rare skin cancers while also offering insight into the value of differentiating among these tumor types based on their relationship with sun exposure, potentially informing preventative, diagnostic and/or therapeutic approaches. [ABSTRACT FROM AUTHOR]

Pleomorphic dermal sarcoma (PDS) is a fast-growing mesenchymal tissue tumor with similar characteristics to an atypical fibroxanthoma (AFX) presenting a significant clinical challenge to diagnose for physicians. We report a 79-year-old male presenting with a 3-month history of a lesion on his scalp that had been previously superficially biopsied yielding a diagnosis of PDS or AFX. Following a second biopsy, new findings led to the diagnosis of PDS. A wide local excision with 2 cm margin with delayed split-thickness skin graft reconstruction was performed. Treatment for PDS favors wide local excision with a 2–3 cm margin and adjuvant radiotherapy if perineural involvement. We support the following recommendations: full-thickness appropriate tissue diagnosis, pulmonary computed tomography scan, or X-ray to rule out metastasis, followed by a multidisciplinary team evaluation. These complex cases should be presented at a tumor board and tailored treatments should be based on patient risk factors and relevant history.

An 88-year-old male patient presented with a large mass on the left lateral bulbar conjunctiva. The tumor appeared two months after the resection of a conjunctival atypical fibroxanthoma (AFX) performed by a cornea specialist. Magnetic resonance imaging of the orbits showed deep orbital invasion along the lateral rectus muscle. The mass and the entire conjunctival sac were totally excised with lid-sparing orbital exenteration. Histopathological analysis confirmed that the mass was an extension of the AFX. Two weeks after surgery, large B-cell lymphoma was diagnosed in the oropharynx. Chemotherapy was initiated, and after seven months of follow-up, there was no recurrence of the AFX. The authors believe that this is the first report of orbital invasion by AFX. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigated a new imaging technique called ex vivo confocal microscopy to examine rare skin conditions. By analyzing tissue samples from different skin disorders, we found that this technique could accurately identify unique microscopic features of both common and rare skin diseases. Importantly, examiners with more experience in interpreting these images achieved higher accuracy in diagnosis. This suggests that ex vivo confocal microscopy has the potential to be a valuable tool alongside traditional methods for diagnosing rare skin conditions early and accurately, leading to better treatment outcomes for patients. While ex vivo confocal laser scanning microscopy has previously demonstrated its utility in most common skin diseases, its use in the assessment of dermatological entities with lower incidence remains unexplored in most cases. We therefore aimed to evaluate the diagnostic efficacy of some rare skin tumors as well as a few inflammatory skin diseases, that have not yet been studied in ex vivo confocal laser scanning microscopy. A total of 50 tissue samples comprising 10 healthy controls, 10 basal cell carcinoma, 10 squamous cell carcinoma, and 20 rare skin conditions were imaged using the newest generation ex vivo confocal microscopy (Vivascope 2500 M-G4, Vivascope GmbH, Munich, Germany). Three blinded investigators were asked to identify characteristic features of rare skin disorders and distinguish them from more common skin diseases in the ex vivo confocal microscopy images. Our findings present the capability of ex vivo confocal microscopy to display distinctive morphologic patterns in common and rare skin diseases. As might be expected, we found a strong correlation between imaging experience and diagnostic accuracy. While the imaging inexperienced dermatohistopathologist reached 60% concordance, the imaging-trained dermatologist obtained 88% agreement with dermatohistopathology. The imaging-trained dermatohistopathologist achieved concordance up to 92% with gold-standard dermatohistopathology. This study highlights the potential of ex vivo confocal laser scanning microscopy as a promising adjunct to conventional dermatohistopathology for the early and precise identification of rare dermatological disorders. [ABSTRACT FROM AUTHOR]

This case report describes an 80-year-old man who presented with a growing erythematous nodule with erosion, measuring 0.6 cm × 0.6 cm, on his right temple. This lesion was later diagnosed as atypical fibroxanthoma (AFX). Instead of undergoing Mohs surgery, the gold standard treatment, the patient opted to pursue a topical treatment regimen because of financial costs associated with surgical removal and repair. This topical regimen consisted of tazarotene cream, imiquimod cream, and 5-fluorouracil solution, applied for 30 days. The patient was directed to use this combination 5 days per week for 6 weeks. The specified dosage for each medication was a fifth of a packet of imiquimod 5% cream, an equivalent amount of tazarotene 0.1% cream, and a single drop of 5-fluorouracil 2% solution. These were combined on a bandage and placed on the lesion overnight. Following the treatment, a 3-week post-application examination revealed an erosion, 1.0 cm × 0.9 cm, amidst erythema. A subsequent incisional biopsy with histopathology and stains for CD10 and CD99, 3 weeks after treatment, and three punch biopsies with histopathology and stains for CD10 and CD99, 1-year post-treatment, confirmed the absence of AFX. AFX is a superficial variant of pleomorphic dermal sarcoma (PDS), which shares histologic similarities, yet the exact relationship between AFX/PDS and undifferentiated pleomorphic sarcoma is still not well understood. Previous studies have indicated a genomic similarity between AFX/PDS and cutaneous squamous cell carcinoma (cSCC), which suggests the potential efficacy of cSCC-targeted treatments for AFX/PDS. This case marks the first recorded instance of successful topical medical treatment of AFX, offering an alternative for patients who may opt out of surgical intervention. Continued research to assess the broader efficacy of this approach is encouraged. [ABSTRACT FROM AUTHOR]

Summary: Background and Objectives: Previous work has demonstrated that hydrochlorothiazide (HCTZ) is a risk factor for squamous cell carcinomas (SCC) and basal cell carcinomas (BCC) due to pro‐photocarcinogenic effects. Atypical fibroxanthoma (AFX) and pleomorphic sarcoma (PDS), both ultraviolet‐induced cancers, display a rare but rising cutaneous tumor entity. This study aimed to evaluate if the use of HCTZ is higher in patients with AFX/PDS than in patients with SCC/BCC and subsequently may be a risk factor for AFX/PDS‐development. Patients and Methods: In a retrospective study of four German skin cancer centers, AFX/PDS cases and SCC/BCC controls were sex and age matched (1:3) over a time‐period of 7 years (2013–2019) to evaluate the use of HCTZ, immunosuppressive medication, second malignancies, and presence of diabetes mellitus. Results: Overall, 146 AFX/PDS and 438 controls (SCC/BCC) were included in the study. The use of HCTZ was significantly higher in patients with AFX/PDS (44.5%) compared to patients with SCC/BCC (25.3%). Additionally, the presence of diabetes mellitus was significantly higher in AFX/PDS patients. Conclusions: This study demonstrates a significantly higher use of HCTZ in patients with AFX/PDS compared to SCC/BCC. This result suggests that HCTZ may be a risk factor for AFX/PDS. Additionally, diabetes mellitus or its comorbidities may be associated with an increased risk for AFX/PDS. [ABSTRACT FROM AUTHOR]

Key Clinical Message An 83‐year‐old man presented an elevated skin lesion in the left temporal area. The resected specimen was identified between a basal cell carcinoma and an atypical fibroxanthoma. A final diagnosis of basal cell carcinoma and atypical fibroxanthoma was made. This study reports a rare case of a cutaneous collision.

Abstract This case report describes an 80-year-old man who presented with a growing erythematous nodule with erosion, measuring 0.6 cm × 0.6 cm, on his right temple. This lesion was later diagnosed as atypical fibroxanthoma (AFX). Instead of undergoing Mohs surgery, the gold standard treatment, the patient opted to pursue a topical treatment regimen because of financial costs associated with surgical removal and repair. This topical regimen consisted of tazarotene cream, imiquimod cream, and 5-fluorouracil solution, applied for 30 days. The patient was directed to use this combination 5 days per week for 6 weeks. The specified dosage for each medication was a fifth of a packet of imiquimod 5% cream, an equivalent amount of tazarotene 0.1% cream, and a single drop of 5-fluorouracil 2% solution. These were combined on a bandage and placed on the lesion overnight. Following the treatment, a 3-week post-application examination revealed an erosion, 1.0 cm × 0.9 cm, amidst erythema. A subsequent incisional biopsy with histopathology and stains for CD10 and CD99, 3 weeks after treatment, and three punch biopsies with histopathology and stains for CD10 and CD99, 1-year post-treatment, confirmed the absence of AFX. AFX is a superficial variant of pleomorphic dermal sarcoma (PDS), which shares histologic similarities, yet the exact relationship between AFX/PDS and undifferentiated pleomorphic sarcoma is still not well understood. Previous studies have indicated a genomic similarity between AFX/PDS and cutaneous squamous cell carcinoma (cSCC), which suggests the potential efficacy of cSCC-targeted treatments for AFX/PDS. This case marks the first recorded instance of successful topical medical treatment of AFX, offering an alternative for patients who may opt out of surgical intervention. Continued research to assess the broader efficacy of this approach is encouraged.

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. [ABSTRACT FROM AUTHOR]

Pleomorphic dermal sarcoma (PDS) is a rare dermal-based mesenchymal tumor that shares histologic characteristics with atypical fibroxanthoma (AFX), but demonstrates aggressive features increasing the risk of local recurrence or metastases. We report a unique case of a 62-year-old man with a recent history of left-groin PDS, now with a 2-cm pedunculated left tonsillar mass and two hypermetabolic nodules in the left thyroid. Microscopically, the tonsillar biopsy demonstrated infiltrating spindle cell neoplasm composed of highly pleomorphic tumor cells with abundant mitoses. The left hemithyroidectomy specimen also demonstrated similar pleomorphic spindled tumor cells infiltrating thyroid parenchyma with perineural invasion and focal osseous and chondroid components. Immunohistochemically, both tumors were diffusely positive for smooth muscle actin. Focal nonspecific positive staining with p53, SATB2, and S100 was observed in the thyroid tumor. Additional markers, including p40, CK5, p63, pancytokeratin, CAM5.2, S100, SOX10, Melan-A, HMB45, CD45, CD68, CD163, caldesmon, p16, TTF1, PAX8, and calcitonin, were all negative. INI-1 expression was retained. Molecular analysis showed that the tumor harbored PDGFRA deletion of exon 9 and amplification, PTCH1 A300fs*24, MDM2 amplification, CDKN2A/B loss, and FRS2 amplification. Compared with the patient's groin tumor, the current tumors showed similar morphology. Overall, the histologic and immunohistochemical findings are consistent with metastatic PDS to the tonsil and thyroid. Although PDS is commonly found on the sun-exposed skin in the elderly, this case highlights an unusual primary site as well as peculiar locations for the metastasis of PDS. Treatment and management of the patient are also considered. [ABSTRACT FROM AUTHOR]

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.

(1) Background: Rare skin cancers include epithelial, neuroendocrine, and hematopoietic neoplasias as well as cutaneous sarcomas. Ultraviolet (UV) radiation and sunburns are important drivers for the incidence of certain cutaneous sarcomas; however, the pathogenetic role of UV light is less clear in rare skin cancers compared to keratinocyte cancer and melanoma. In this study, we compared the degree of actinic elastosis (AE) as a surrogate for lifetime UV exposure among selected rare skin cancers (atypical fibroxanthoma [AFX], pleomorphic dermal sarcoma [PDS], dermatofibrosarcoma protuberans [DFSP], Kaposi sarcoma [KS], Merkel cell carcinoma [MCC], and leiomyosarcoma [LMS]) while taking into account relevant clinical variables (age, sex, and body site). (2) Methods: We newly established a semi-quantitative score for the degree of AE ranging from 0 = none to 3 = total loss of elastic fibers (basophilic degeneration) and multiplied it by the perilesional vertical extent (depth), measured histometrically (tumor-associated elastosis grade (TEG)). We matched the TEG of n = 210 rare skin cancers from 210 patients with their clinical variables. (3) Results: TEG values were correlated with age and whether tumors arose on UV-exposed body sites. TEG values were significantly higher in AFX and PDS cases compared to all other analyzed rare skin cancer types. As expected, TEG values were low in DFSP and KS, while MCC cases exhibited intermediate TEG values. (4) Conclusions: High cumulative UV exposure is more strongly associated with AFX/PDS and MCC than with other rare skin cancers. These important results expand the available data associated with rare skin cancers while also offering insight into the value of differentiating among these tumor types based on their relationship with sun exposure, potentially informing preventative, diagnostic and/or therapeutic approaches.

Resumen: Introducción y objetivo: El fibroxantoma atípico (FXA) y el sarcoma pleomórfico dérmico (SPD) son neoplasias de origen mesenquimal poco frecuentes. Debido a la baja incidencia del SPD y a una nomenclatura históricamente confusa existe poca información acerca de la verdadera agresividad de este tumor. Realizamos el presente estudio con el objetivo de identificar qué características clínicas y/o histológicas del SPD son predictoras de riesgo de recidiva. Material y método: Se diseñó un estudio bicéntrico observacional retrospectivo de 31 casos de SPD diagnosticados y tratados en el Hospital Clínico Universitario de Valencia y el Instituto Valenciano de Oncología, entre los años 2005 y 2020. Se realizó un análisis descriptivo de las características clínicas e histológicas, un análisis inferencial univariado y un análisis multivariado mediante la regresión de Cox. Resultados: En el análisis univariado, la recidiva tumoral (p

The prognosis of patients with atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) remains uncertain and no standardized follow-up programs have been established. To recommend a standardized follow-up program of patients with AFX and PDS based on nationwide long-term estimates of local recurrence and metastasis. 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. 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. Risk of misclassification and lack of detailed surgical information. 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. [ABSTRACT FROM AUTHOR]

Introduction: Pleomorphic dermal sarcoma (PDS) is an uncommon cutaneous mesenchymal neoplasm. It is cytomorphologically identical to atypical fibroxanthoma (AFX), but differs due to its invasion beyond the dermis. We undertook an examination of our experience with fine needle aspiration (FNA) biopsy cytology of PDS. Materials and Methods: Our cytopathology files were searched for examples of PDS with concomitant histopathological verification. FNA biopsy smears and cell collection were performed using standard techniques. Results: Seven cases of PDS were retrieved from four different patients (M:F, 1:1; age range: 63–88 years; mean age = 78 years). All patients (57%) presented with a primary tumour with one having an FNA biopsy of two local recurrences and a single distant metastasis. Five aspirates were from the extremities and two from the head/neck. Tumours ranged from 1.0 to 3.5 cm (mean, 2.2 cm). Specific cytological diagnoses were pleomorphic spindle/epithelioid sarcoma (3 cases), PDS (2), AFX (1), and atypical myofibroblastic lesion, query nodular fasciitis (1). Immunohistochemical (IHC) staining from FNA‐generated cell blocks in two cases showed non‐specific staining with vimentin in both cases; positive CD10, CD68, and INI‐1 staining in one case; and smooth muscle actin expression in the other. Multiple negative stains were performed in both of these cases to exclude malignant melanoma, carcinoma, and specific forms of sarcoma. Cytopathology consisted of a mixture of spindle, epithelioid, and bizarre pleomorphic cells. Conclusion: Coupled with ancillary IHC stains, FNA biopsy can help recognise PDS as a sarcomatous cutaneous neoplasm, but is unable to distinguish PDS from AFX. [ABSTRACT FROM AUTHOR]

Atypical fibroxanthomas are rare, superficial dermal tumors. Most cases are benign and only locally destructive with a low rate of metastasis. Lesions are most commonly found on sun-exposed sites of elderly light-skinned patients and present as asymptomatic nodules with irregular borders; ulcerations and friability are other key characteristics. Pedunculated lesions, however, are rarely described in the literature. We present two cases of atypical fibroxanthoma manifesting as exophytic, pedunculated lesions on the face: one in a 74-year-old man and the other in an 82-year-old woman. These tumors are very effectively treated by excision with Mohs micrographic surgery.

Under the umbrella of cutaneous sarcomas (CS) we include a heterogeneous group of rare, malignant, mesenchymal neoplasia, such as dermatofibrosarcoma protuberans, atypical fibroxanthoma, cutaneous undifferentiated pleomorphic sarcoma, cutaneous angiosarcoma and leiomyosarcoma. Clinical presentation and histopathological examination are the cornerstone of CS diagnosis and classification. There are scarce data in the literature in regards to the clinical and dermatoscopic characteristics of CS and the role of dermatoscopy in their early identification. We performed a literature review, aiming to summarize current data on the clinical and dermatoscopic presentation of the most common types of cutaneous sarcomas that may facilitate early diagnosis and prompt management. Based on the available published data, CS are characterized by mostly unspecific dermatoscopic patterns. Dermatofibrosarcoma protuberans, Kaposi's sarcoma, and in a lesser degree, cutaneous angiosarcoma, may display distinct dermatoscopic features, facilitating their early clinical recognition. In conclusion, dermatoscopy, in conjunction with the overall clinical context, may aid towards suspicion of CS. [ABSTRACT FROM AUTHOR]

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Summary: Background: The histogenetic origin of atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) has not been definitively elucidated. In addition to a fibroblastic origin, a keratinocytic differentiation is discussed due to strong clinical, histomorphological and molecular genetic similarities with undifferentiated cutaneous squamous cell carcinoma (cSCC). Patients and Methods: 56 cases (36 AFXs, 8 PDSs, 12 undifferentiated cSCCs) were evaluated for their clinical, histomorphological, and immunohistochemical characteristics. RNA transcriptome analysis was performed on 18 cases (6 AFXs/PDSs, 6 undifferentiated cSCCs, 6 differentiated cSCCs). Results: Clinically, the strong similarities in age, gender and tumor location were confirmed. Without further immunohistochemical staining, histomorphological differentiation between AFX/PDS and undifferentiated cSCC is often impossible. Principal component analysis of the RNA transcriptome analysis showed that AFX/PDS and differentiated cSCC each formed their own cluster, while the undifferentiated cSCCs fall in between these two groups, but without forming a cluster of their own. When examining differentially expressed genes (DEGs), the heat maps showed that there were cases within the undifferentiated cSCC that were more likely to be AFX/PDS than differentiated cSCC based on their expression profile. Conclusions: The results provide evidence of molecular similarities between AFX/PDS and undifferentiated cSCC and suggest a common histogenetic origin. [ABSTRACT FROM AUTHOR]

Atypical fibroxanthoma (AFX) is a rare cutaneous fibrohistiocytic tumor that typically arises on chronically sun-damaged skin, such as the head and neck, as a nondescript ulcerated papule, nodule, or tumor. The clinical prognosis is usually favorable and metastasis is rare. Pleomorphic dermal sarcoma (PDS), or undifferentiated pleomorphic sarcoma, is a recently introduced diagnostic moniker for AFX-like tumors with more aggressive clinical and histologic features such as necrosis and vascular invasion. The exact relationship between AFX and PDS has been debated. Diagnosis of these tumors is generally based on immunohistochemical staining to exclude other mimics. A wholly specific marker for this tumor does not exist, leading to diagnostic ambiguity in certain cases. Herein, we present a case of pleomorphic dermal sarcoma in a 53-year-old man with human immunodeficiency virus that displayed patchy S100 staining concerning for melanoma upon hospital pathology review. Next-generation sequencing analysis confirmed a mutation pattern consistent with published molecular signatures of AFX/PDS. In discussing this case, we review the current understanding of AFX/PDS and discuss diagnostic pitfalls, as well as emphasize on how next-generation sequencing techniques might improve accuracy in the diagnosis of tumors in the spectrum of AFX/PDS.

Atypical fibroxanthoma (AFX) is a rare dermal spindle-cell sarcoma, considered a relatively benign type of skin cancer. Clinically, it presents as localized red nodules or plaques, and most commonly affects the head and neck of elderly individuals with sun-damaged skin. In this report, we present the case of a 92-year-old woman diagnosed with AFX on the left dorsum. Initially, she underwent surgical excision and was followed up in the clinic. However, after a 10-month follow-up period, the tumor recurred, and a second surgical excision was performed. Pathological examination revealed a malignant fibrous histiocytoma transformation of the AFX, a rare occurrence in the prognosis of AFX.

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 one 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. [ABSTRACT FROM AUTHOR]

Summary: Background and objectives: In recent years, considerable insight has been gained into the pathogenesis, diagnosis and treatment of cutaneous sarcomas, including atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS). Both entities have shown increasing incidence rates in the last decade. This study was initiated to evaluate how these new insights impact the number of diagnoses of AFX/PDS compared to other cutaneous sarcoma entities. Patients and methods: In a retrospective study of four German skin cancer centers, all histopathological reports of cutaneous sarcomas (AFX, PDS, dermatofibrosarcoma protuberans, cutaneous leiomyosarcoma, angiosarcoma, and Kaposi sarcoma) confirmed by board‐certified dermatopathologists were analyzed during a time‐period of seven years (2013–2019). Additionally, utilization of immunohistochemical markers (including pan‐cytokeratin, S100, desmin, CD34, CD10, procollagen‐1, CD99, CD14, and CD68) as an adjunct to diagnose AFX/PDS was recorded. Results: Overall, 255 cutaneous sarcomas were included in the present study. The diagnosis of a cutaneous sarcoma has consequently risen from 2013 to 2019 (from 16 to 52 annual cases). The results of AFX/PDS revealed 4.6 times more diagnoses in 2019 than in 2013. Atypical fibroxanthoma represented the most common subtype, displaying 49.3 % of all diagnosed cutaneous sarcomas. Additionally, the increase of AFX/PDS was linked to the use of immunohistochemistry, with specific immunohistochemical markers used in 57.1 % of cases in 2013 compared to 100 % in 2019. Conclusions: This retrospective study of four German skin cancer centers demonstrates a substantial rise of AFX/PDS, possibly due to recently established diagnostic and terminology standards. This rise is probably linked to increased utilization of specific immunohistochemical markers. Atypical fibroxanthoma/PDS may be more common than previously thought and seems to represent the most frequent cutaneous sarcoma subtype. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Pleomorphic dermal sarcoma (PDS) and atypical fibroxanthoma (AFX) are rare mesenchymal tumors that share similar clinical, histological, and immunohistochemical characteristics. Careful histopathological examination of a biopsy specimen that includes subcutaneous fat remains the preferred way to differentiate between these tumors. AFX is limited to dermal invasion, whereas PDS demonstrates deeper invasion. Moreover, PDS may present with tumor necrosis and high-grade histological findings, such as lymphovascular and perineural invasion, features absent in AFX. However, like PDS, AFX is a diagnosis of exclusion, and an exhaustive immunohistochemistry panel is recommended to distinguish these tumors from other spindled cell tumors in the differential diagnosis. The authors present the case of an 86-year-old man with biopsy-suspected AFX who was referred for Mohs micrographic surgery for tumor excision. During Mohs, the tumor was observed to have invaded deeply into the subcutaneous tissue and galeal aponeurosis, aligning more closely with a PDS. The diagnosis of PDS was confirmed using en face processing during Mohs surgery, which captured the intravascular involvement of a solitary vessel. Differentiating between PDS and AFX is important because PDS is a more aggressive tumor, with a higher rate of local recurrence and metastasis, and requires closer monitoring., Competing Interests: Conflict of Interest None declared

We report the case of a Hispanic male whose conjunctival atypical fibroxanthoma (AFX) grew very large, with intraocular as well as extraocular muscle extensions, and was treated with exenteration. A 50-year-old male presented with a one-month history of foreign-body sensation in his left eye. The initial examination revealed an erythematous, vascularized, pedunculated lesion arising from the left eye conjunctiva. A tissue biopsy from the lesion confirmed the diagnosis of an AFX with a small component of squamous cell carcinoma. The patient was intermittently lost to follow-up until, one-and-a-half years after his initial visit, he underwent an exenteration of the left eye as the tumor had intraocular and extraocular muscle extensions. Subsequently, he was scheduled for ongoing monitoring., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Ramirez Marquez et al.)

Atypical fibroxanthoma (AFX) with osteoclast‐like giant cells is a rare entity. We present the case of an elderly woman who presented with a pink–purple dome‐shaped nodule with central hyperkeratotic crust. Biopsy revealed a cellular, dermal‐based tumor comprised of spindle, oval, and osteoclast‐like giant cells with pleomorphism. The immunohistochemistry profile supported a diagnosis of AFX with osteoclast‐like giant cells. We performed a literature review through PubMed and Google Scholar for AFX with osteoclast‐like giant cell formation and found 16 previously reported cases. We aim to provide a review and discuss features of these cases. We also discuss the pathogenesis of these osteoclast‐like cells as well as potential pitfalls in diagnosis. [ABSTRACT FROM AUTHOR]

Resumen: La relación entre el fibroxantoma atípico (FXA) y el sarcoma pleomórfico dérmico (SPD) ha sido confusa y objeto de debate a lo largo de los años en la literatura científica. Son tumores que se presentan en pacientes de edad avanzada en piel fotoexpuesta, típicamente cabeza y el cuello. Están formados por una mezcla variable de células histiocitoides, fusiformes, epitelioides y gigantes multinucleadas con núcleos pleomórficos. No existen técnicas inmunohistoquímicas diagnósticas de estas entidades y su diagnóstico debe ser de exclusión. El FXA es una neoplasia dérmica, bien delimitada, con ausencia de infiltración difusa de tejido subcutáneo, necrosis tumoral o invasión linfovascular o perineural. Estando alguna de las características anteriores presente, debe hacerse el diagnóstico de SPD. En esta revisión narrativa de la literatura intentaremos determinar cuáles son las características histopatológicas precisas de ambas entidades, según las series publicadas en la literatura y aquellos aspectos que las diferencian o relacionan. Abstract: 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.

Under the umbrella of cutaneous sarcomas (CS) we include a heterogeneous group of rare, malignant, mesenchymal neoplasia, such as dermatofibrosarcoma protuberans, atypical fibroxanthoma, cutaneous undifferentiated pleomorphic sarcoma, cutaneous angiosarcoma and leiomyosarcoma. Clinical presentation and histopathological examination are the cornerstone of CS diagnosis and classification. There are scarce data in the literature in regards to the clinical and dermatoscopic characteristics of CS and the role of dermatoscopy in their early identification. We performed a literature review, aiming to summarize current data on the clinical and dermatoscopic presentation of the most common types of cutaneous sarcomas that may facilitate early diagnosis and prompt management. Based on the available published data, CS are characterized by mostly unspecific dermatoscopic patterns. Dermatofibrosarcoma protuberans, Kaposi’s sarcoma, and in a lesser degree, cutaneous angiosarcoma, may display distinct dermatoscopic features, facilitating their early clinical recognition. In conclusion, dermatoscopy, in conjunction with the overall clinical context, may aid towards suspicion of CS.

Numerous cells with very large and irregular nuclei ("monster" cells) have not hitherto been reported in desmoplastic melanoma (DM). Their prognostic significance in melanomas is a matter of debate, although some authors have associated them with more aggressive tumor behavior. We report a mixed DM on the scalp of an 88-year-old woman imitating an atypical fibroxanthoma. Tumor cells stained positive for SOX10, S100, and cyclin D1; BRAF mutation status was negative, and fluorescence in situ hybridization analysis showed copy number gains in 11q13 (cyclin D1) and 6p25 (RREB1), and loss in 6q23 (MYB). Cyclin D1 amplification is associated with poor prognosis in melanoma. [ABSTRACT FROM AUTHOR]

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., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.