Dermatology Online Journal

Porokeratosis plantaris, palmaris, et disseminata
Ming H Jih MD PhD
Dermatology Online Journal 9(4): 34

From the Ronald O. Perelman Department of Dermatology, New York University

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Abstract

A 66-year-old woman presented with thick, hyperkeratotic papules and plaques on the plantar aspects of both feet as well as more superficial, annular, hyperkeratotic papules on the chest, neck, and face. A biopsy was consistent with porokeratosis. The clinical findings are consistent with porokeratosis plantaris, palmaris, et disseminata.

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Clinical summary

History.—A 66-year-old woman had a 20-year history of scaly skin on the feet, legs, hands, arms, chest, neck, and face. The patient presented to the Bellevue Hospital Medical Center dermatology clinic for treatment of hyperkeratotic and pruritic lesions on her feet, which had been present for more than 20 years. Over time, similar lesions also had developed on her hands, face, neck, and chest. These lesions were slightly pruritic and of cosmetic concern. She had been treated with isotretinoin intermittently for many years with some improvement and with acitretin (25 mg) for the past few years with continued slight improvement. The lesions on the face, neck, and chest also had been treated with light electrodesiccation with some improvement. Various topical glucocorticoids as well as topical 5-fluorouracil, retinoic acid, and salicylic acid had been tried without benefit. Past medical and family history was otherwise unremarkable.

Physical examination.—Thick, hyperpigmented and hyperkeratotic papules, some becoming confluent plaques, were found on the plantar surfaces of both feet. Smaller, hyperkeratotic lesions were noted on the hands. Thin, hyperkeratotic papules, some with distinct, raised, annular borders, were scattered in large numbers across the chest, neck, and face. The oral mucosa was clear.

Figure 1	Figure 2

Laboratory data.—None.

Histopathology.—There is a sparse, lymphocytic infiltrate in the upper part of the dermis, above which there is focal thinning of the epidermis and coronoid lamellae.

Diagnosis.—Porokeratosis plantaris, palmaris, et disseminata.

Comment

Porokeratosis has been described as having five distinct clinical subtypes: Mibelli or plaque type, which is usually a single or a few large plaques that are several centimeters in diameter; disseminated superficial actinic porokeratosis (DSAP), in which small discrete lesions are scattered in mostly sun-exposed areas of the extensor extremities; linear porokeratosis; punctate porokeratosis, which is limited to the palms and soles; and porokeratosis plantaris, palmaris, et disseminata. The clinical findings in this case are most consistent with porokeratosis plantaris, palmaris, et disseminata, in which lesions first appear typically on the palms and soles and then gradually spread to other areas of the body. The lesions are typically thick and confluent on the palms and soles, can cause disability, and may be associated with severe pruritus [1]. Lesions on the body tend to be smaller and more discrete and superficial with the classic peripheral ridge that is characteristic of porokeratosis.

Risk factors for the development of porokeratosis include genetic inheritance, ultraviolet radiation, and immunosuppression [2]. An autosomal dominant mode of inheritance has been established for familial cases of porokeratosis [3]. Although the etiology of porokeratosis remains unclear, abnormal early keratinocyte apoptosis underlying the area of the coronoid lamella, has been demonstrated with disruption of loricrin expression, which indicates that dysregulation of terminal differentiation of keratinocytes may be involved [4]. Rarely, squamous cell carcinoma or basal cell carcinoma have been reported in patients with Mibelli or linear types of porokeratosis [5, 6]. It has been postulated that an abnormal clone of keratinocytes may lie at the base of the parakeratotic column, and both chromosomal instability and reduced immune surveillance may play a role in the development of cutaneous malignant conditions within lesions of porokeratosis. Overexpression of P53 tumor suppressor protein has been found in lesions of porokeratosis [7].

Treatment is dependent on the type and extent of the lesion and should first involve sun protection, emollients, and observation for signs of malignant degeneration. If lesions are widespread and medical treatment is desired, topical treatments such as salicylic acid and retinoic acid may be tried. Topical 5-fluorouracil has been shown to induce remission in all forms of porokeratosis [8]. Topical vitamin D3 analogues, such as calcipotriol and tacalcitol, have been shown to be effective after 3-6 months of treatment for DSAP [9,10]. Topical imiquimod was shown to be effective for the treatment of porokeratosis of Mibelli [11]. In refractory cases, low-dose oral retinoids, such as isotretinoin or acitretin, can be utilized. Although side effects and long-term risks limit prolonged use of these medications, it is possible that the use of oral retinoids in immunosuppressed patients, who are at higher risk for malignant degeneration, may reduce the risk of carcinoma developing in porokeratotic lesions. For refractory cases, the combination of oral retinoids with topical 5-fluorouracil has been reported to be effective for DSAP and porokeratosis plantaris, palmaris, et disseminata [12]. Surgical modalities may improve cosmesis and function but frequently are followed by relapses. Cryotherapy and electrodesiccation and curettage can be used to treat small lesions, and both dermabrasion and Grenz ray have been reported to be useful [13]. Although carbon dioxide laser ablation has been used with success, there is a high rate of recurrence. The 585-nm flashlamp-pumped pulsed-dye laser was effective in one case of linear porokeratosis [14], and the frequency-doubled Nd:YAG laser was helpful for one patient with DSAP [15].

References

1. Shaw JC, White CR Jr. Porokeratosis plantaris palmaris et disseminata. J Am Acad Dermatol 11:454, 1984.

2. Zenarola P, et al. Exacerbation of porokeratosis: a sign of immunodepression. J Am Acad Dermatol 29:1035, 1993.

3. Anderson DE, Chernosky ME. Disseminated superficial actinic porokeratosis: Genetic aspects. Arch Dermatol 99: 408, 1969.

4. Shen CS, et al. Premature apoptosis and dysregulation of keratinization in porokeratosis. Br J Dermatol 147:498, 2002.

5. Sasson M, Krain AD. Porokeratosis and cutaneous malignancy: A review. Dermatol Surg 22: 339, 1996.

6. Seishima M, et al. Squamous cell carcinoma arising from lesions of porokeratosis palmaris et plantaris disseminata. Eur J Dermatol 10: 478, 2000.

7. Magee PR, et al. Overexpression of P53 tumor suppressor protein in porokeratosis. Arch Dermatol 130:187, 1994.

8. Shelley WB, Shelley ED. Disseminated superficial porokeratosis: Rapid therapeutic response to 5-fluorouracil. Cutis 32: 139, 1983.

9. Harrison PV, Stollery N. Disseminated superficial actinic porokeratosis responding to calcipotriol. Clin Exp Dermatol 19: 95, 1994.

10. Bohm M, et al. Disseminated superficial actinic porokeratosis: Treatment with topical tacalcitol. J Am Acad Dermatol 40: 479, 1999.

11. Agarwal S, Berth-Jones J. Porokeratosis of Mibelli: Successful treatment with 5% imiquimod cream. Br J Dermatol 146:338, 2002.

12. Sander CA, et al. Chemotherapy for disseminated actinic keratoses with 5-fluorouracil and isotretinoin. J Am Acad Dermatol 36: 236, 1997.

13. Ricci C, et al. Bullous and pruritic variant of disseminated superficial actinic porokeratosis: successful treatment with grenz rays. Dermatology 199:328, 1999.

14. Alster TS, Nanni CA. Successful treatment of porokeratosis with 585 nm pulsed dye laser irradiation. Cutis 63:265, 1999.

15. Liu HT. Treatment of lichen amyloidosis (LA) and disseminated superficial porokeratosis (DSP) with frequency-doubled Q-switched Nd:YAG laser. Dermatol Surg 26: 958, 2000.

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