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Genital porokeratosis

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Genital porokeratosis
Christine Liang MD, Priya Batra MD, Rishi Patel MD, Hideko Kamino MD
Dermatology Online Journal 15 (8): 23

Department of Dermatology, New York University


A 22-year-old man presented with a two-year history of warts on the penis, scrotum, and thighs. Physical examination showed multiple annular plaques with thin, threadlike borders on the penis and scrotum. The biopsy specimen showed a cornoid lamella with underlying dyskeratotic cells that was consistent with porokeratosis. Genital porokeratosis is a rare condition that may be misdiagnosed as a sexually transmitted disease.

Figure 1Figure 2


A 22-year-old man presented to the Dermatology Clinic at Bellevue Hospital Center in July, 2008, with a two-year history of warts on the shaft of his penis, thighs, scrotum, and perianal area. An external biopsy report brought in by the patient had been interpreted as condyloma acuminata. The patient was treated at an outside clinic with podophyllin and cryotherapy and noted improvement of the perianal lesions but limited improvement of the lesions on the penis and scrotum.

Past medical history was noncontributory. The patient was sexually active with both men and women and reported a history of unprotected sex. He denied a prior history of sexually transmitted diseases. The patient took no medications. A punch biopsy was obtained from a lesion on the scrotum.

Physical Examination

On the dorsal shaft of the penis were multiple, small, annular plaques with a thin, threadlike border. Numerous, arcuate, erythematous plaques with borders consisting of small erythematous papules were noted on the scrotum. On the left inguinal fold were multiple verrucous papules and plaques. The perianal area was clear.

Laboratory data

A rapid plasma reagin test was nonreactive. Urine DNA amplification testing for gonorrhea and chlamydia were negative.


Within a hyperplastic epidermis there is a dell with hypogranulosis, dyskeratosis, and an overlying column of parakeratosis, which is consistent with a cornoid lamella. Beneath this is a band-like lymphohistiocytic infiltrate.


Porokeratosis is a disorder of keratinization that is characterized by centrifugally spreading patches, which are surrounded by a ridge-like border with central atrophy. Porokeratosis involving the genital area is uncommon and can occur as part of generalized involvement or as localized porokeratosis that is confined to the genital area. The localized form is rare, with less than 20 cases reported in the literature [1, 2, 3]. More common clinical variants include plaque-type porokeratosis of Mibelli, disseminated superficial actinic porokeratosis, linear porokeratosis, porokeratosis palmaris et plantaris disseminata, and punctate porokeratosis.

Histopathologic examination shows a classic cornoid lamella with underlying dyskeratotic cells. Clinically, genital porokeratosis may have the typical elevated border of porokeratosis lesions but often is misdiagnosed as condyloma, syphilis, granuloma annulare, lichen simplex chronicus, or eczema. Cases of genital porokeratosis coexisting with sexually transmitted diseases (condyloma acuminatum and syphilis) have been reported [1]. Thus, genital porokeratosis is probably underdiagnosed and might be treated as a sexually transmitted disease.

Localized treatment of genital porokeratosis includes cryotherapy, carbon dioxide laser, surgery, topical 5-fluorouracil, imiquimod, or topical diclofenac [1, 5]. Resolution of lesions has been reported in some, but not all, of the lesions treated with these regimens. Topical glucocorticoids or retinoids achieved only symptomatic relief.

Malignant change has been reported in nearly all types of porokeratosis but has not been reported in genital porokeratosis. A review of malignant transformation found that these changes were more frequent on non-exposed skin, in large porokeratosis lesions, and in patients who previously received radiation therapy [4]. Therefore, long-term follow-up for genital porokeratosis lesions is reasonable and long-term follow-up studies are needed.


1. Chen T, et al. Genital porokeratosis: a series of 10 patients and review of the literature. Br J Dermatol 2006;155:325 [PubMed]

2. Sengupta S, et al. Porokeratosis confined to the genital area: a report of three cases. Indian J Dermatol Venereol Leprol 2008;74:80 [PubMed]

3. Laino L, et al. Genital porokeratosis. Eur J Dermatol 2004;14:190 [PubMed]

4. Otsuka F, et al. Porokeratosis and malignant skin tumors. J Cancer Res Clin Oncol 1991;117:55 [PubMed]

5. Kluger N, et al. Genital porokeratosis: treatment with diclofenac topical gel. J Dermatol Treatment 2007;18:188 [PubMed]

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