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A case of verrucous psoriasis

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A case of verrucous psoriasis
Holly R Monroe BS1, Joseph D Hillman MD2, Melvin W Chiu MD MPH1,3
Dermatology Online Journal 17 (5): 10

1. Division of Dermatology, Department of Medicine
2. Department of Pathology and Laboratory Medicine
David Geffen School of Medicine at the University of California, Los Angeles (UCLA), Los Angeles, California.
3. Dermatology Service, West Los Angeles Veterans Administration Medical Center, Los Angeles, California


Psoriasis is a common inflammatory disease with a range of clinical presentations and a chronic relapsing course. There have been few reports of verrucous psoriasis, which is distinguished by its warty appearance and characteristic histology. We report a case of this rare form of psoriasis in an elderly woman with a history of plaque-type psoriasis and and discuss the histopathologic findings.


Psoriasis is a common inflammatory disease with a range of clinical presentations and a chronic relapsing course. We report a case of a rare clinical variant, verrucous psoriasis, and discuss the histopathology.


Figure 1Figure 2
Figure 1. Hyperkeratotic verrucous papule on the trunk

Figure 2. Hyperkeratotic verrucous papule on the trunk

An 84-year-old female with a history of plaque psoriasis of ten years duration, nonmelanoma skin cancer, atrial fibrillation, and hypothyroidism presented with a flare of psoriatic plaques and new verrucous hyperkeratotic growths (Figures 1 and 2). The patient was chronically on coumadin and levothyroxine and there had been no changes to her medication regimen. She denied use of alternative medications or any supplements. On exam, widespread pink patches and plaques were observed on her chest, abdomen, back, and lower extremities. Four asymptomatic hyperkeratotic verrucous papules and plaques were noted on the posterior arm, lumbosacral back, thigh, and distal leg; these were biopsied to rule out squamous cell carcinoma, although seborrheic keratoses, warts, and psoriasis were also considered clinically. Eight months later the patient presented with another flare with three similar verrucous plaques on her chest and abdomen (which were biopsied) as well as erythematous, scaly plaques on her chest, abdomen, and back.

Figure 3Figure 4
Figure 3. Psoriasiform epidermal hyperplasia with prominent papillomatosis and abundant parakeratosis (H&E, x4)

Figure 4. Munro microabscesses and spongiform pustules of Kogoj (H&E, x40)

Figure 5
Figure 5. More conventional area of psoriasis (Munro microabscess, hypogranulosis, acanthosis, and thin suprapapillary epidermal plates) with inward bending of rete ridges towards the center of the lesion (epithelial buttressing) (H&E, x20)

These seven biopsies procured from the patient demonstrated psoriasiform epidermal hyperplasia with papillomatosis (Figures 3 through 5). These biopsies also demonstrated marked parakeratosis and hyperkeratosis, solitary units and collections of neutrophils within the stratum corneum and stratum spinosum, epidermal hypogranulosis, thin suprapapillary epidermal plates, epithelial buttressing (inward bending of peripheral rete ridges towards the center of the lesion), and a superficial perivascular, lymphocyte-predominant inflammatory infiltrate. Six biopsies demonstrated admixed plasma cells. Three biopsies demonstrated a few eosinophils. PAS and Steiner stains were negative.

The patient was diagnosed with verrucous psoriasis and initially started on topical fluocinonide and keratolytic agents, urea and salicylic acid, which produced resolution of the plaques on her extremities and chest. However, she continued to develop more plaques on her trunk. Clobetasol and calcipotriene were also used, but the patient continued to have erythematous, verrucous plaques on her extremities and trunk. The patient declined systemic agents because of her concern for adverse effects.

In the past, the patient’s psoriasis was treated and controlled with etanercept but she discontinued the medication more than 1 year prior to the described flare because of decreased effect and her concerns for adverse effects. The patient reported that her psoriasis did not significantly improve on prior UVB phototherapy. She subsequently began acitretin 25 mg daily, which she discontinued after less than 3 months owing to bothersome alopecia that developed. She opted to use topical steroids such as triamcinolone, halobetasol, clobetasol, and betamethasone/calcipotriene combination ointments despite continued flares.


Verrucous psoriasis (VP) is a rare variant of psoriasis with wart-like changes clinically and histologically. VP may be simultaneously uncommon and confused with other lesions, including verruca vulgaris, epidermal nevus, contact dermatitis, eczema, and fungal infection [1]. In a case report, verrucous plaques on the lower extremities that responded to acitretin are speculated to have been VP masquerading as verrucous carcinoma [2, 3].

Beek and van Reede observed that of over 250 biopsies of psoriasis lesions from 178 patients, parakeratosis, hyperkeratosis, acanthosis and an abnormal capillary pattern were uniformly observed and Munro abscesses and spongiform pustules of Kogoj were frequently concomitant findings [4]. It is well-established that histopathologic findings of psoriasis include parakeratosis, epidermal acanthosis with elongation of rete ridges, thin suprapapillary epidermal plates, epidermal hypogranulosis, and dilated, tortuous capillaries and a lymphocyte-predominant inflammatory infiltrate, which may contain admixed neutrophils in the papillary dermis [5]. Neutrophil collections in the stratum corneum and stratum spinosum, called Munro microabcesses and spongiform pustules of Kogoj, respectively, are the most specific findings for psoriasis [5]. Additional findings of papillomatosis, epithelial buttressing, and the absence of infection suggest VP. For example, in a case series of twelve patients with an average age of 61.8 and nine with known psoriasis, the lesions on the extensor surfaces of extremities demonstrated similar histopathologic findings [1]. In a 22-year-old female, pruritic annular lesions of VP showed prominent papillomatosis on histology similar to warts [6]. A 60-year-old male with plaque psoriasis and verrucous papules on his hand had a biopsy that showed cup shaped acanthosis, epidermal invagination, and parakeratosis, along with microabcesses, which may suggest histologic subtypes of VP [7]. Verruca superimposed on psoriatic plaque was considered in our patient. However, our patient was immunocompetent and had no other wart-like lesions,, no brown-black dots suggestive of thrombosed capillaries, and no vacuolated keratinocytes or koilocytosis on histologic examination. Furthermore, the characteristic findings of Munro microabscesses and spongiform pustules of Kogoj argue in favor of a diagnosis of psoriasis.

The pathology in our case was fairly prototypical. Interestingly, six of seven biopsies demonstrated admixed plasma cells in the intradermal inflammatory infiltrate. The presence of plasma cells is unusual for psoriasis [8] and raises the possibility of secondary syphilis, HIV [9], or a psoriasisform drug eruption such as can be secondary to Tumor Necrosis Factor-alpha inhibitor use [10]. A Steiner stain demonstrated no spirochetes and there were no other clinical or laboratory findings to support syphilis. Whereas three biopsies demonstrated a few eosinophils in the intradermal inflammatory infiltrate and a verrucous psoriasiform eruption secondary to interferon has been reported [11], the clinical history was not suggestive of a drug eruption in our patient. She was not on any new medications or supplements and had been off of etanercept for over a year. The patient had no history of high-risk behavior, recurrent infections, or lymphopenia to suggest HIV infection. The finding of plasma cells in this case may be a unique characteristic of VP and merits further investigation.

Little is known about the pathogenesis and treatment of VP, and there is inadequate evidence to negate the mainstay treatments for psoriasis. Additional investigation is necessary to determine an optimal treatment regimen for verrucous psoriasis but the rarity of this disease limits the ability to conduct such a study.


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