Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2025;15(3):5455 1 Clinical and Histopathological Insights into Acantholytic Dyskeratotic Acanthoma: A Case Series Buğra Burç Dağtaş1, Cem Leblebici2, Cemre Büşra Türk3, Asude Kara Polat4, Ayşe Esra Koku Aksu1 1 University of Health Sciences, Istanbul Training and Research, Department of Dermatology, Istanbul, Turkey 2 University of Health Sciences, Istanbul Training and Research, Department of Pathology, Istanbul, Turkey 3 Massachusetts General Hospital, Department of Surgery, Harvard Medical School, MA, USA 4 Istanbul Arel University, Memorial Hospital, Department of Dermatology, Istanbul, Turkey Key words: Acantholytic dyskeratotic acanthoma, Acantholysis, Dyskeratosis, Acanthoma Citation: Dağtaş BB, Leblebici C, Türk CB, Polat AK, Koku Aksu AE. Clinical and Histopathological Insights into Acantholytic Dyskeratotic Acanthoma: A Case Series. Dermatol Pract Concept. 2025;15(3):5455. DOI: https://doi.org/10.5826/dpc.1503a5455 Accepted: June 4, 2025; Published: July 2025 Copyright: ©2025 Dağtaş 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: Buğra Burç Dağtaş, MD. University of Health Sciences, İstanbul Training and Research Hospital, Department of Dermatology, Istanbul /Turkey. Orcid ID: 0000-0002-9592-9968. E-mail: bugradagtas@gmail.com Introduction Acantholytic dyskeratotic acanthoma (ADA) is a rare epider- mal lesion characterized by acantholysis and dyskeratosis. First described in 2007, ADA typically presents as solitary papules or plaques less than 1 cm in diameter, confirmed histopathologically [1]. Clinically, ADA may mimic verruca vulgaris, irritated seborrheic keratosis (ISK), squamous cell carcinoma (SCC), and basal cell carcinoma (BCC). The pres- ence of confluent acantholytic dyskeratosis is critical for diag- nosis. Due to histological similarities with other acantholytic dermatoses, accurate differential diagnosis is essential [2]. This study evaluated the clinical and histopathological fea- tures of eight patients diagnosed with ADA, aiming to expand the limited cumulative data in the literature and highlight key distinguishing features to aid in accurate diagnosis. Case Presentations The patients, aged 49 to 89 years, had a mean age of 65.0 ±14.0 years; 62.5% were male and 37.5% female (Table 1). Two patients had BCC, one had non-Hodgkin lymphoma (NHL) with prior radiotherapy, and one had bladder car- cinoma. The mean lesion duration was 14.6 ±19.4 months, with a median of six months. Lesions averaged 8.9 ±5.4 mm in size, with a median of 8 mm. The majority of lesions were located on the trunk (50%), followed by the thigh (37.5%) and the gluteal region (12.5%) (Figure 1). All patients under- went complete surgical excision. The most frequent differential diagnoses included ver- ruca vulgaris (22.1%), ISK (22.1%), and actinic keratosis (16.7%). Histopathological analysis revealed hyperkerato- sis and acanthosis in all cases, with psoriasiform acanthosis 2 Research Letter | Dermatol Pract Concept. 2025;15(3):5455 T ab le 1 . P at ie nt C ha ra ct er is ti cs , L es io n Fe at ur es , a nd H is to lo gi ca l F in di ng s in A ca nt ho ly ti c D ys ke ra to ti c A ca nt ho m a. C as e (N o) A ge (y ea rs ) Se x K no w n D is ea se D ur at io n (m on th s) L oc al i- za ti on D if fe re nt ia l di ag no si s Si ze (m m ) H yp er ke ra - to si s A ca nt ho si s L ev el o f A ca nt ho ly si s L ev el o f D ys ke ra to ti c C el ls C on flu en t A pp ea ra nc e C or p R on ds G ra in Su pr ab as al C le ft Fo rm at io n Su pe rfi ci al Ly m ph oc yt e In fil tr at io n 1 54 M N H L 60 L ef t th ig h B ow en , S C C , C ut . M et 20 + + Su pr ab as al / ep id er m is lo w er le ve l Sp in al la ye r + – – – + 2 49 M – 12 R ig ht th ig h W ar t, IS K , A K 3 + (P ro m in en t ke ra ti n ho rn ) + E pi de rm is lo w er le ve l Sp in al la ye r – – + – + 3 82 F B C C 6 T ru nk A K , S C C 8 + + E pi de rm is lo w er le ve l Sp in al la ye r + + + – + 4 89 M B C C 6 T ru nk B C C 4 + + Su pr ab as al / ep id er m is lo w er le ve l Sp in al la ye r + + – + + 5 68 M B la dd er C A 1 G lu te a D F, S K 10 + + (P so ri as if or m ) Su pr ab as al / ep id er m is lo w er le ve l Sp in al la ye r – – + + + 6 60 F – 6 T ru nk W ar t, IS K 6 + + Su pr ab as al / ep id er m is lo w er le ve l Sp in al la ye r + – – + + 7 63 F – 22 R ig ht th ig h W ar t, IS K 12 + + E pi de rm is lo w er le ve l Sp in al la ye r + – + + + 8 55 M – 4 T ru nk A K , I SK , W ar t 8 + + E pi de rm is lo w er le ve l Sp in al la ye r – – – – – M : M al e, F : F em al e; A bb re vi at io ns : N H L : n on -H od gk in ly m ph om a; B C C : b as al c el l c ar ci no m a; B la dd er C A : b la dd er c ar ci no m a; I SK : i rr it at ed s eb or rh ei c ke ra to si s; S C C : s qu am ou s ce ll ca rc in om a; A K : a ct in ic k er at os is ; D F: d er m at of ib ro m a; S K : s eb or rh ei c ke r- at os is ; C ut . M et : c ut an eo us m et as ta si s; B ow en : B ow en ’s d is ea se ; + : p re se nc e of h is to pa th ol og ic al f in di ng ; – : a bs en ce . Research Letter | Dermatol Pract Concept. 2025;15(3):5455 3 observed in one case. Confluent acantholytic dyskeratosis was observed in 62.5% of cases, suprabasal cleft formation in 50%, corps ronds in 25%, and grain in 50%. Dyskeratotic cells were consistently localized to the spinous layer, and superficial lymphocytic infiltration was present in 87.5% of cases. Acantholysis was identified in the suprabasal/ epidermal lower layers in four cases and the lower epidermal layers in the remaining four. Conclusion ADA is a rare but distinct entity that can clinically mimic malignancies. Limited case series in the literature highlight its importance in differential diagnosis. The lesion size and locations observed in this series are consistent with previous reports, with a predominance on the trunk and average di- ameter below 1 cm [2,3]. Histopathologically, ADA is characterized by confluent acantholytic dyskeratosis and suprabasal cleft formation— observed in 62.5% and 50% of cases, respectively—which are crucial for differentiation from other dermatoses. The absence of nuclear atypia is a key distinguishing feature from SCC and actinic keratosis [2,3]. Although the etiopathogenesis of ADA remains unclear, prior studies have suggested a potential link to immunosup- pression [4-6]. Further studies are needed to elucidate the role of immunological factors in ADA. Complete surgical excision remains the most effective diagnostic and therapeutic method, as confirmed by this series [3]. ADA should be recognized as a rare but clinically rele- vant entity that can be managed effectively when correctly diagnosed. Our case series contributes valuable cumulative data and reinforces the importance of complete excision and histological confirmation in ambiguous solitary lesions. Further studies are warranted to better define its etiopatho- genesis and guide diagnostic criteria. Statement of Ethics: The study was conducted ethically in accordance with the World Medical Association Declaration of Helsinki. Ethics Committee approval was not required for this study by national guidelines. Informed Consent: Written informed consent was obtained from all patients for the publication of their medical details and accompanying clinical images. Figure 1. (A) Hyperkeratotic corn-covered, indurated papule with an erythematous base, measuring 3 mm in di- ameter, located on the right thigh. This clinical presentation correlates with the orthohyperkeratosis and follicular involvement observed histologically in panel (D). (B) Brownish papule measuring 4 mm with slight central erosion, located on the trunk. The central erosion is reflected histologically by the focal acantholysis and sparse dyskeratotic keratinocytes observed in panel (E). (C) Plaque approximately 2 cm in size with an erythematous base and a black crust of about 1 cm, located on the trunk. This appearance corresponds to the dense acantholytic areas and prom- inent dyskeratotic cells illustrated in panel (F). (D) Irregular acanthosis and orthohyperkeratosis in the epidermis, with a hyperkeratotic column extending from the hair follicle infundibulum to the surface (H&E, x40). (E) Focal and minimal acantholysis in the hair follicle epithelium, sparse dyskeratotic cells, and keratinocytes with prominent eosinophilic cytoplasm (H&E x200). (F) Sparse dyskeratotic cells and eosinophilic keratinocytes in the acantholytic area (H&E x400; blue arrow: dyskeratotic cells; green arrow: acantholysis). 4 Research Letter | Dermatol Pract Concept. 2025;15(3):5455 4. Bürgler C, Schlapbach C, Feldmeyer L, Haneke E. Multiple ac- antholytic dyskeratotic acanthomas in an organ transplant re- cipient. JAAD Case Rep. Aug 2018;4(7):695-697. doi:10.1016/j. jdcr.2018.04.009. 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