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CORRESPONDENCE
Year : 2023 | Volume
: 41
| Issue : 1 | Page : 60-61
Subungual acantholytic dyskeratotic acanthoma: A case report
Chia-Hsiang Chung1, Yang-Chih Lin2, Yu-Hung Wu3
1 Department of Dermatology, MacKay Memorial Hospital, Taipei, Taiwan
2 Department of Dermatology, MacKay Memorial Hospital; Department of Cosmetic Science and Management, MacKay Medicine, Nursing and Management College, Taipei, Taiwan
3 Department of Dermatology, MacKay Memorial Hospital, Taipei; Department of Medicine, MacKay Medical College, New Taipei City, Taiwan
Correspondence Address:
Dr. Yu-Hung Wu
Department of Dermatology, MacKay Memorial Hospital, No. 92, Sec. 2, Zhongshan North Road, Taipei 10449
Taiwan
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/ds.DS-D-23-00007
Dear Editor,
Acantholytic dyskeratotic acanthoma is a benign epidermal tumor of the keratinocytes which was first described by Omulecki et al. in 2007.[1] A variant of subungual acantholytic dyskeratotic acanthoma (SADA) was subsequently reported.[2] However, this subungual variant is rare. We report the case of a 54-year-old male presenting with painful whitish streak on his right thumb for several days and no obvious previous trauma to the lesion site. Clinical examination revealed a longitudinal xanthonychia and distal wedge-shaped onycholysis [Figure 1]a and [Figure 1]b. Soft-tissue sonography revealed a 2.44 mm × 3.21 mm × 4.37 mm blurred hypoechoic nonvascular lesion in the proximal nail bed and matrix [Figure 1]c and [Figure 1]d. Hand X-ray showed no apparent bony pathology. The initial clinical diagnosis was onychopapilloma. Nail bed and matrix longitudinal biopsy after nail plate removal were performed [Figure 1]b. Pathologically, there was inflammation and fibrosis in the onychodermis close to the nail matrix [Figure 2]a. The nail matrix contained suprabasal acantholysis [Figure 2]b. The distal nail bed epithelium close to the hyponychium was acanthotic and had foci of diffuse acantholysis and dyskeratosis [Figure 2]c and [Figure 2]d. Periodic acid–Schiff stain showed a few fungal budding spores in the subungual area, possibly due to secondary colonization. The final diagnosis was SADA. No recurrence was noted after excision.
Figure 1: (a) A longitudinal xanthonychia with wedge-shaped distal onycholysis on the right thumb nail. (b) On nail removal, one whitish-yellowish triangular thin plaque was seen on the nail bed. A longitudinal biopsy following the marks was performed. (c and d) A 2.44 mm × 3.21 mm × 4.37 mm blurred hypoechoic lesion in the proximal nail bed and matrix
Figure 2: Pathology of subungual dyskeratotic acanthoma. (a) Scanning view of the lesion. Inflammation and fibrosis close to the nail matrix are more prominent. (b) Suprabasal acantholysis is found in the nail matrix. (c) Acanthosis and diffuse acantholysis in the distal nail bed close to the hyponychium. This part corresponds to the yellowish papule which is seen during the surgery. (d) Closer view of acantholysis and dyskeratosis. (H & E. original magnification, a x 1; b x 400; c x 200; d x 400)The term acantholytic dyskeratosis describes a histopathological pattern of suprabasal acantholysis associated with dyskeratosis. Many diseases present this pattern, including tumors such as warty dyskeratosis and acantholytic dyskeratotic acanthoma and inflammatory diseases such as Darier disease and Hailey–Hailey disease.[2],[3]
SADA has rarely been reported. This term was first described by Sass et al. in 2009 with a series of three cases.[2] Ng et al. subsequently reported another case.[3] Two more cases of nail lesions with suprabasal acantholytic cleft and dyskeratotic cells consistent with SADA were found in the literature.[4],[5] Among these six cases and ours, there were three men and three women.[2],[3],[4],[5] Their ages ranged from 12 to 73 years. Four patients had lesions located on the right thumb, one on the right 4th finger, and another on the left 3rd finger. Clinically, they had various and overlapping presentations, including longitudinal erythronychia (five cases), distal onycholysis (three cases), subungual hyperkeratotic papule at the free edge (three cases), xanthonychia (two cases), and splinter hemorrhage (two cases).[2],[3],[4],[5] Our case showed xanthonychia and onycholysis without erythronychia and subungual hyperkeratosis, but location was also on the right thumb. The clinical presentation may mimic onychopapilloma or other subungual tumors.
The pathogenesis of SADA is still unknown. Various factors, including infection, immunologic factors, and physical stimuli, have been hypothesized.[6] In most previously reported SADA cases, the etiology was not mentioned. Suppuration was found in one case and raised the association of such lesions with infection.[2] Nevertheless, most lesions occurred on the right thumb, suggesting that an external trauma may play a role.
Differential diagnoses of SADA include subungual warty dyskeratoma, Darier disease, or pemphigus with nail involvement.[7],[8] They share a similar pathology with suprabasilar acantholysis and dyskeratosis. In subungual warty dyskeratoma and Darier's disease, similar clinical appearances, including longitudinal erythronychia, leukonychia, and distal subungual hyperkeratosis, are reported.[7],[8] Paronychia and onychomadesis have been found in pemphigus with nail involvement.[8]
In conclusion, SADA is a rare nail lesion that may mimic other inflammatory or neoplastic nail diseases. Pathology is essential to reach the correct diagnosis.
Ethical approval
This study was approved by the IRB of MacKay Memorial Hospital (22MMHIS392e), and the patient informed consent was waived by the IRB.
Financial support and sponsorship
Nil.
Conflicts of interest
Dr. Yu-Hung Wu, an editorial board member at Dermatologica Sinica, had no role in the peer review process of or decision to publish this article. The other authors declared no conflicts of interest in writing this paper.
References
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