Porokeratosis superficialis disseminata actinica Q82.8

Not rare, hereditary or also non-hereditary, acquired, disseminated form of porokeratosis in light-exposed areas. The single-cell lesion is a skin-colored, punctate-onset, centrifugally progressing, hard, hyperkeratotic papule with formation of an annular, parakeratotic horny ridge as well as central atrophy. Usually multiple single foci.

Irregular autosomal dominant inheritance can be detected in some patients.

Several cytogenetic aberrations have been detected on the following gene loci: 1p31.3-p31.1 - 15q25.1-q26.1 and others (the mutated proteins include involucrin on chromosome 1q21.3).

However, most patients deny a familial occurrence.

Excessive UV exposure can be detected in almost all cases. A combination with immunosuppression (HIV infection; immunosuppressive therapies) is not uncommon.

Disseminated superficial eosinophilic porokeratosis can be induced by medication (thiazides) or occur spontaneously.

Mostly occurring in fair-skinned adults with increased sun exposure, mostly 40th-50th LJ, women seem to be preferentially affected.

Back of the hand, forearm extension sides, lower leg extension sides, no mucosal involvement.

Round to oval, 0.2-0.5-1.5 cm in size, skin-colored or brownish-red, slightly sunken horny papules or plaques with sharply defined, hyperkeratotic marginal ridge. With prolonged persistence, characteristic annular plaques may form, giving a characteristic stamp to the clinical picture.

A characteristic feature is the so-called cornoid lamella (columnar, nucleated corneocyte clusters); underneath is a narrowed epidermis with stratification disorder and dyskeratosis. If porokeratosis is suspected, the skin sample should be taken from the peripheral area of the lesion, as this is where the typical histological criteria are found.

Keratosis follicularis; keratosis actinica; psoriasis vulgaris; verrucae planae juveniles; acrokeratosis verruciformis.

• Physical procedures such as curettage or ablative lasers (Co2 or Erbium YAG laser)
• Vitamin D3 analogs
• Fluorouracil therapy
• Photodynamic therapy
• In a smaller study (Schilling B 2018), good results were reported with so-called borderline radiation (long-wave, soft X-rays).
• Imiquimod
• Tretinoin
• Another treatment option is topical diclofenac in combination with etretinate (Shimizu S et al. 2018)
• Sunscreen (e.g. Anthelios), see also sunscreen below.
• Cream with lovastatin 2 % and cholesterol 2 %

Progression with increasing age, especially in the summer months. The risk of malignant transformation to squamous cell carcinoma or basal cell carcinoma is reported to be 7.5% to 10% (Shimizu S et al 2018).

Notice. Provocation by UV rays and drugs (thiazides)!

Superficial eosinophilic porokeratosis: As a special form, "Superficial eosinophilic porokeratosis" is described with eosinophilic spongiosis and intraepidermal microabscesses.

Eruptive pruriginous papular porokeratosis: A further, but very rare variant (up to now <15 cases have been described) is the "Eruptive pruriginous papular porokeratosis" which is characterized by a sudden itching. The plumelike parakeratosis zones are related to the follicle. Eosinophilic granulocytes are also an essential part of the inflammatory infiltrate in this form.

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2. Besenhard HM et al (1988) Disseminated superficial actinic porokeratosis (DSAP) with Bowen's disease. Dermatol 39: 286-290
3. Biswas A (2015) Cornoid lamellation revisited: apropos of porokeratosis with emphasis on unusual clinicopathological variants. Am J Dermatopathol 37:145-155
4. Boente Mdel C et al (2003) Linear porokeratosis associated with disseminated superficial actinic porokeratosis: a new example of type II segmental involvement. Pediatr Dermatol 20: 514-518
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6. Chernosky ME, Anderson DE (1969) Disseminated superficial actinic porokeratosis: clinical studies and experimental production of lesions. Arch Derm 99: 401-407
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8. Nayeemuddin FA et al (2002) Topical photodynamic therapy in disseminated superficial actinic porokeratosis. Clin Exp Dermatol 27: 703-706
9. Schilling B (2018) Marginal radiation in refractory actinic porokeratosis: a tolerable and effective therapy. Karger Compass 6:32-33
10. Schwarz T et al (1984) Disseminated superficial actinic porokeratosis. J Am Acad Dermatol 11: 724-730.

11. Shimizu S et al (2018) Inflammatory disseminated superficial porokeratosis successfully controlled with a combination of topical diclofenac gel and systemic etretinate. J Eur Acad Dermatol Venereol 32:e201-e202.

12. Sidwell RU et al (2003) Giant actinic porokeratosis of the scalp. Br J Dermatol 149: 654
13. Takahashi H et al (2015) Disseminated superficial actinic porokeratosis in a psoriasis patient with a long-term sun-bathing habit. J Dermatol 42:532-533
14. Theng CT et al (2004) Warty nodules on an annular plaque in a renal transplant recipient. Arch Dermatol 140: 121-126
15. Thomas C et al (2003) Hypertrophic perianal porokeratosis in association with superficial actinic porokeratosis of the leg. Clin Exp Dermatol 28: 676-677
16. Torkamani N et al (2015) Disseminated superficial actinic porokeratosis accentuated by spray tan. Int J Dermatol 54:e545-546