Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2025;15(3):5296 1 Cutaneous Angiosarcoma Mimics Basal Cell Carcinoma: Utility of Optical Super-High Magnification Dermoscopy in Differential Diagnosis Stefania Guida1,2, Gianmarco Diego Bigotto1,2, Giorgio Stabile1,2, Antonio Podo Brunetti1,2, Nathalie Rizzo3, Franco Rongioletti1,2 1 School of Medicine, Vita-Salute San Raffaele University, Milan, Italy 2 Dermatology Clinic, IRCCS San Raffaele Hospital, Milan, Italy 3 Pathology Unit, IRCCS San Raffaele Hospital, Milan, Italy Key words: Cutaneous angiosarcoma, Optical super high magnification dermoscopy, Dermoscopy, OSHMD Citation: Guida S, Bigotto GD, Stabile G, et al. Cutaneous Angiosarcoma Mimics Basal Cell Carcinoma: Utility of Optical Super- High Magnification Dermoscopy in Differential Diagnosis. Dermatol Pract Concept. 2025;15(3):5296. DOI: https://doi.org/10.5826/ dpc.1503a5296 Accepted: May 5, 2025; Published: July 2025 Copyright: ©2025 Guida et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Gianmarco Diego Bigotto, MD, Clinic Dermatology Unit – Ospedale San Raffaele. Via Olgettina 60, 20132, Milano, Italy. E-mail: bigotto.gianmarco@hsr.it https://orcid.org/0009-0002-7010-8255 Introduction Angiosarcomas are rare, aggressive malignancies with poor prognoses that arise from endothelial cells lining blood ves- sels. They can occur in various body sites but are most com- monly found in the skin, particularly on the head and neck of elderly individuals. Cutaneous angiosarcomas can mimic other conditions, thereby delaying proper diagnosis and treatment. Clinically, these skin cancers appear as violaceous patches or plaques, but they can exhibit a wide range of pre- sentations and can resemble benign lesions such as bruises or eczema, or rarely, other malignancies like basal cell carci- noma (BCC) [1-3]. We describe a lesion of the scalp that mimicked an ulcer- ated BCC for which we used optical super-high magnifica- tion dermoscopy (OSHMD), an advanced imaging technique enabling ×400 magnification of dermoscopic pictures. The integration of clinical-dermoscopic findings and OSHMD features led to a prompt skin biopsy, revealing an angiosar- coma with histopathological examination. Case Presentation An 81-year-old woman suffering from rheumatoid arthritis, who denied taking any drugs, presented for a plaque located on the scalp. According to her medical history, the lesion had appeared after a trauma six months prior and had persisted over time. Clinical examination revealed a 5 × 3.5 cm plaque on the mid scalp, half of which was ulcered (Figure  1A). On dermoscopy, white shiny areas and arborescent vessels over a pink background and ulceration were observed (Figure 1B). 2 Research Letter | Dermatol Pract Concept. 2025;15(3):5296 Figure 1. A case of a cutaneous angiosarcoma. (A) Ulcerated 5 × 3 cm plaque located on the mid scalp. (B) Dermoscopy of the lesion. Half of the image represents the cen- tral ulcerated part with atypical vessels (blue arrow), the other half the peripheral pink part with crystalline structures and arborescent in-focus vessels (red arrow). (C) Optical super-high magnification dermoscopy (OSHMD), ×400: a focus on arborizing vessels. (D) OSHMD (x400): a focus on irregular looped blue-purple vessels. (E) Histopathol- ogy: irregular anastomosing vascular channels lined with atypical endothelial cells (H&E staining, original magnification, ×400). (F) Endothelial cells express CD31 marker on immunohistochemistry. Further, the lesion was explored with OSHMD, highlighting arborizing vessels as well irregularly looped blue-purple ves- sels (Figure 1, C and D). Interestingly, dermoscopic findings together with arborescent vessels observed with OSHMD were suggestive for a possible diagnosis of BCC. However, the history of the relatively recent appearance in relation to the size of the lesion and the irregularly looped blue-purple ves- sels did not support our suspicion of BCC, thus prompting a biopsy and histological examination. Histology revealed irreg- ular anastomosing vascular channels lined with atypical en- dothelial cells (Figure 1E). Additional immunohistochemistry showed positivity for CD31 and ERG, supporting the diagno- sis of cutaneous angiosarcoma (Figure 1F). The proliferative activity evaluated with Ki-67 was equal to 50%. Because of the nature of the neoplasm, the patient was referred to the Sarcoma Operating Unit for overall management of the case. Research Letter | Dermatol Pract Concept. 2025;15(3):5296 3 Conclusion This report describes a case of cutaneous angiosarcoma mimicking BCC, with possible implications for diagnostic delay and worse prognosis. Clinical and dermoscopic find- ings in angiosarcomas have been described previously [4]. BCC represents a rare condition for differential diagnosis, as reported in sporadic case reports [1,2]. Recently, the use of OSHMD for skin cancer analysis has been introduced. While arborescent and regular red looped vessels in OSHMD (Figure 2) have been identified and de- scribed in BCC [5], the observation of irregularly looped blue-purple vessels with OSHMD (Figure 1D) in our case might assist in early diagnosis of aggressive skin cancers and lead to better patient management. 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Morphology of Vessels in Basal Cell Carcinoma in Optical Super-high Magnifi- cation Dermoscopy. Acta Derm Venereol. 2023;103:adv11966. DOI:10.2340/actadv.v103.11966. PMID: 37529846. Figure 2. Dermoscopic and optical super-high magnification der- moscopy (OSHMD) findings in basal cell carcinoma (BCC). (A) Dermoscopy of a BCC: pinkish lesion with arborescent vessels. (B) OSHMD (×400x): a focus on regular looped vessels of BCC.