*Dermatology Department, Hospital de Manises, Valencia, Spain
†Dermatology Department, Instituto Valenciano de Oncologia, Valencia, Spain
The authors declare no funding or conflicts of interest.
To the Editor:
Warty dyskeratoma (WD) is considered a disorder of keratinization characterized by a single solitary papule or nodule that histopathologically reveals acantholytic dyskeratosis. Multiple WD is an extremely rare condition that, to the best of our knowledge, has been previously reported in a few cases. Thus, this entity is not clinically and epidemiologically well established and its definition could lead to avoid a misdiagnosis.
A 76-year old man, with a 10-year history of psoriasis controlled with weekly dose of oral methotrexate (10 mg/week), presented a 6-month history of multiple mild pruritic lesions on his trunk, clinically reminiscent of a hypertrophic lichen planus. Neither familial nor personal history of disorders of keratinization was found.
Physical examination showed several firm brownish umbilicated papules and nodules, sited on the chest and back. These multiple papules varied in size, ranging between 0.5 and 1.3 cm. (Fig. 1). Histological examination showed a large well-circumscribed epidermal invagination lined mainly at the periphery and at the base by epithelial cells extending into the papillary dermis, acquiring “cup-shaped” architecture (Fig. 2). The invagination was partially covered by a parakeratotic plug and was surrounded by an epidermal collarette and a hyperplastic epidermis with hypergranulosis and papillomatous features reminiscent of verruca vulgaris. Epithelial component revealed foci of acantholysis and dyskeratosis. Papillary dermis showed a scanty lymphocytic infiltration with no other relevant feature. The biopsy was reviewed by 3 dermatopathologists (O.S., V.T., and A.M.C.), establishing the final diagnosis of multiple WD.
WD is a relatively uncommon benign skin lesion, first described by Helwig1 in 1954 as “isolated Darier's disease.” This pathology presents mostly as an isolated papule or nodule on the scalp, face, and neck of adults.2 In a few cases, involvement of the oral and genital mucosa has been reported.2 WD lesions show mainly 3 different architectural patterns, namely, cup-shaped, cystic, and nodular, the former being the most frequent.2
Multiple WD is an exceptional finding, which has previously been reported in a few cases, mostly in Japan. They present as multiple painless or pruritic grouped verrucous papules on the head, and in lesser frequency, on the trunk.3,4
The etiology is uncertain, and despite the presence of histopathologic findings resembling viral warts, recent studies did not detect any evidence of HPV infection.2 Other possible etiological factors, including ultraviolet light, autoimmunity, chemical carcinogens, and tobacco have been suggested. Nevertheless, these lesions display overall histopathologic features consistent with a follicular adnexal neoplasm and the term “follicular dyskeratoma” has been proposed to better reflect the distinctive features of this peculiar lesion.2
The most important histopathologic differential diagnoses of multiple WD are Darier disease, Grover disease, hypertrophic actinic keratosis, and multiple squamous cell carcinomas. The diagnosis of multiple WD is established based on its characteristic clinical and histopathological features.2
Well-demarcated and slow-growing WD lesions are usually stable by the time they reach 1–2 cm in size. Total surgical excision is the treatment of choice,2 but topical tazarotenic acid gel may provide successful results in the management of this dyskeratotic disorder.5 The current case was successfully managed with 0.1% tazarotene gel daily.
Recurrence is rare, and malignant transformation of neither solitary nor multiple WD has been reported. However, the association between the multiple subtype and renal failure, based on 3 previously reported cases, has been suggested.3,4
In summary, multiple WD is an exceptional entity that could be misdiagnosed mainly with other entities characterized by multiple papular and pruritic lesions. Its diagnosis should lead us to rule out a possible renal involvement.
1. Helwig EB. Proc of the 10th Seminar on the Skin Neoplasms and Dermatoses, American Society of Clinical Pathology, International Congress of Clinical Pathology, Washington, DC, 11 September 1954. Washington: The American Society of Clinical Pathology; 1955:53–56.
2. Kaddu S, Dong H, Mayer G, et al.. Warty dyskeratoma—“follicular dyskeratoma”: analysis of clinicopathologic features of a distinctive follicular adnexal neoplasm. J Am Acad Dermatol. 2002;47:423–428.
3. Koç M, Kavala M, Kocatürk E, et al.. Multiple warty dyskeratomas on the scalp. Dermatol Online J. 2009;15:8.
4. Griffiths TW, Hashimoto K, Sharata HH, et al.. Multiple warty dyskeratomas of the scalp. Clin Exp Dermatol. 1997;22:189–191.
5. Abramovits W, Abdelmalek N. Treatment of warty dyskeratoma with tazarotenic acid. J Am Acad Dermatol. 2002; 46:S4.
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