Case Reports
Vol. 18 No. 3 (2026)
https://doi.org/10.4081/dr.2025.10415

Primary malignant melanoma with pseudovascular morphology: a diagnostic pitfall

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Published: 19 November 2025
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Diagnostic pitfall, immunohistochemistry, malignant melanoma, next-generation sequencing, pseudovascular morphology

Authors

Monia Di Prete
https://orcid.org/0000-0002-3881-8540
Dermatopathology Research Unit, San Gallicano Dermatological Institute IRCCS, Rome, Italy.
Paola Pasquini
https://orcid.org/0009-0003-2788-6024
Dermatopathology Research Unit, San Gallicano Dermatological Institute IRCCS, Rome, Italy.
Elisa Melucci
Department of Pathology, Regina Elena National Cancer Institute IRCCS, Rome, Italy.
Viviana Lora
Clinical Dermatology, San Gallicano Dermatological Institute IRCCS, Rome, Italy.
Carlo Cota
carlo.cota@ifo.it
Dermatopathology Research Unit, San Gallicano Dermatological Institute IRCCS, Rome, Italy.

Melanoma is a neoplasm with a heterogeneous clinical presentation and several histopathological variants have been described. Although histopathological evaluation remains the diagnostic gold standard, unusual morphology of some melanomas can lead to pathologic misinterpretation, as they can be confused with other non-melanocytic tumors. Here, we present a case of nodular melanoma with pseudovascular morphology characterized by uncommon empty branching slit-like spaces, reminiscent of rete testis vessels, for which we suggest the name of retiform melanoma to distinguish it from angiomatoid melanoma. Immunohistochemical analysis and ancillary molecular tests helped us characterizing this neoplasm, underscoring the need for clinical-morphological-molecular correlation for the correct diagnosis of unusual cases.

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Crossref
Scopus
Google Scholar
Europe PMC
1. Brenn T. Pitfalls in the evaluation of melanocytic lesions. Histopathology 2012;60:690-705.
2. Brenn T. Melanocytic lesions - Staying out of trouble. Ann Diagn Pathol 2018;37:91-102.
3. Machado I, Llombart B, Cruz J, et al. Desmoplastic melanoma may mimic a cutaneous peripheral nerve sheath tumor: Report of 3 challenging cases. J Cutan Pathol 2017;44:632-8.
4. Cancer Genome Atlas Network. Genomic classification of cutaneous melanoma. Cell 2015;161:1681-96.
5. Cota C, Saggini A, Lora V, et al. Uncommon Histopathological Variants of Malignant Melanoma: Part 1. Am J Dermatopathol 2019;41:243-63.
6. Ambrogio F, Colagrande A, Cascardi E, et al. Partially Dedifferentiated Primitive Malignant Melanoma with Pseudo-Angiomatous Features: A Case Report with Review of the Literature. Diagnostics (Basel) 2023;13:495.
7. Maniotis AJ, Folberg R, Hess A, et al. Vascular channel formation by human melanoma cells in vivo and in vitro: vasculogenic mimicry. Am J Pathol 1999;155:739-52.
8. Jour G, Ivan D, Aung PP. Angiogenesis in melanoma: an update with a focus on current targeted therapies. J Clin Pathol 2016;69:472-83.
9. Modlin RL, Gottlieb B, Taylor C, Rea TH. Identification of cells lining pseudovascular spaces of benign pigmented nevi. Am J Dermatopathol 1984;6:25-9.
10. Ellerhorst JA, Greene VR, Ekmekcioglu S, et al. Clinical correlates of NRAS and BRAF mutations in primary human melanoma. Clin Cancer Res 2011;17:229-35. Erratum in: Clin Cancer Res 2011;17:1641.
11. Hayward NK, Wilmott JS, Waddell N, et al. Whole-genome landscapes of major melanoma subtypes. Nature 2017;545:175-80.
12. AACR Project GENIE Consortium. AACR Project GENIE: Powering Precision Medicine through an International Consortium. Cancer Discov 2017;7:818-31.
13. Flucke U, Vogels RJ, de Saint Aubain Somerhausen N, et al. Epithelioid Hemangioendothelioma: clinicopathologic, immunohistochemical, and molecular genetic analysis of 39 cases. Diagn Pathol 2014;9:131.
14. Randic T, Kozar I, Margue C, et al. NRAS mutant melanoma: Towards better therapies. Cancer Treat Rev 2021;99:102238.
15. Garcia-Alvarez A, Ortiz C, Muñoz-Couselo E. Current Perspectives and Novel Strategies of NRAS-Mutant Melanoma. Onco Targets Ther 2021;14:3709-19.
16. Kilsdonk MJ, Romeijn TR, Kelder W, et al. Angiosarcomatous transdifferentiation of metastatic melanoma. J Cutan Pathol 2020;47:1211-4.

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1.
Primary malignant melanoma with pseudovascular morphology: a diagnostic pitfall. Dermatol Reports [Internet]. 2025 Nov. 19 [cited 2026 Oct. 9];18(3). Available from: https://journals.pagepress.net/dr/article/view/10415
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