Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2022;12(3):e2022135 1 Eccrine Porocarcinoma Arising From an Eccrine Poroma: a Case Report Ingrid Silveira1, Gabriela Siliprandi Lorentz Sartori1, André da Silva Cartell1,2, Thaís Corsetti Grazziotin1 1 Department of Dermatology, Hospital São Lucas, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS) 2 Department of Pathology, Universidade Federal do Rio Grande do Sul (UFRGS) Porto Alegre, Brazil Keywords: eccrine porocarcinoma, eccrine poroma, dermoscopy, sweat gland, tumor Citation: Silveira I, Siliprandi Lorentz Sartori G, da Silva Cartell A, Corsetti Grazziotin T. Eccrine porocarcinoma arising from an eccrine poroma: case report. Dermatol Pract Concept. 2022;12(3):e2022135. DOI: https://doi.org/10.5826/dpc.1203a135 Accepted: December 21, 2021; Published: July 2022 Copyright: ©2022 Silveira et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 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: Thais Corsetti Grazziotin, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS). Email thais.grazziotin@ pucrs.br Dermatology Practical & Conceptual Introduction Eccrine porocarcinoma (EPC) is the malignant counterpart of eccrine poroma (EP) and is mostly found on the lower ex- tremities in elderly adults [1]. EPC may develop as a primary tumor or from a benign long-standing EP with malignant transformation. Dermoscopy is used increasingly to facilitate clinical diagnosis [2]. In this report, we describe a case of an invasive EPC originating in an eccrine poroma and associ- ated with an adjacent satellite lesion of eccrine poroma. Case Presentation A 68-year-old woman referred a vegetative lesion in the right plantar region with one year of evolution. She reports that the lesion appeared after local trauma caused by sandals and complains of pain. On physical examination, it presented as an ulcerated, vegetative, bulky exophytic tumor associated with a satellite small plaque (Figure 1A). Dermoscopy of the lesion showed predominantly round-to-oval shaped pink white structureless areas surrounded by white-to-pink halo and polymorphous vessels including coiled and branched vessels with rounded ending (flower-like vessels) (Figure 1B). Ulcerated areas presented polymorphous vascular pattern with linear irregular and dotted vessels with splinter hem- orrhage (Figure 1C). Histopathology showed that the main lesion was compatible with ulcerated porocarcinoma, in association with an eccrine poroma, invading the inferior reticular dermis, without vascular and perineural invasion (Figure 2, A and B). The satellite lesion was diagnosed as eccrine poroma. There were no signs of postoperative recur- rence or metastasis after 6 months of follow-up. Conclusions EP is a benign tumor of the sweat gland that arises from acrosyringium. EPC is a rare malignant skin tumor that usu- ally appears in the lower limbs of elderly people as nodule, plaque or papule pink to red, sometimes with ulceration [1]. EPC may arise de novo or can originate from malignant transformation of an EP [2]. An EP that shows changes, as sudden growth, ulceration and spontaneous bleeding turns 2 Research Letter | Dermatol Pract Concept. 2022;12(3):e2022135 Figure 1. Clinical and dermoscopic findings. (A) Clinical presentation of an ulcerated, exophytic tumor in the right plantar region associated with a satellite small plaque in the metatarsal region. (B) Dermoscopy of the non-ulcerated component showing round-to-oval shaped pink white structureless areas surrounded by white-to-pink halo (blue asterisks) and polymorphous vessels including coiled and branched vessels with rounded ending (blue arrows). (C) Dermoscopy of ulcerated areas presented polymorphous vascular pattern with linear irregular and dotted vessels (black arrows) with splinter hemorrhage (black asterisks). Figure 2. Histopathological findings. (A) Histology of eccrine poroma showing epidermis with hyperkeratosis and cuboidal poroid nests with small cuboidal cells in closer examination. (B) Infiltrative tumor with proliferation of epidermis and tumor cells forming ductal lumina. Closer examination reveals atypical neoplastic cells and some mitotic figures of porocarcinoma. on the red flag for an arising EPC. In our case the patient had both tumors, EP and EPC, and it seems probable that the EPC originated from the EP. According to previously reported, dermoscopic features may overlap between EPC and EP, such as pink white struc- tureless areas and white-to-pink halo, although in EPC they are present focally in the tumor and do not comprise the entirety of nodules, such as in EP [1]. Vascular pattern is of- ten polymorphous in EPC, usually combining hairpin, dotted and linear irregular vessels, while coiled, glomerular and the typical flower, leaf-like vessels are less frequently found [1]. In the histopathological examination the usual findings in- clude nuclear atypia, increased mitotic activity rate and necrosis. In the clinical examination, infiltrated borders, bleeding, growth and ulceration are important features that may indicate malignancy in EP-like lesions [2]. Since EPC shares multiple features with other tu- mors and is a rare skin neoplasm, diagnosis is a challenge. Anatomopathological signs of invasion and cellular pleo- morphism in an eccrine tumor are clues to the definitive diagnosis [2]. Treatment is necessary due to the aggressive nature of the tumor, and surgery is the first option. References 1. Edamitsu T, Minagawa A, Koga H, Uhara H, Okuyama R. Eccrine porocarcinoma shares dermoscopic characteristics with eccrine poroma: A report of three cases and review of the published work. J Dermatol. 2016;43(3):332-335. DOI: 10.1111/1346-8138.13082. 2. Uchiyama J, Jardim M, Valente N, Camargo MF. The transi- tion between a poroma and a porocarcinoma evidenced by the dermoscopy. An. Bras. Dermatol. 2019;94(2):230-232. DOI: 10.1590/abd1806-4841.20197280. PMID: 31090833; PMCID: PMC6486063.