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CASE REPORT |
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| Year : 2022 | Volume
: 67
| Issue : 6 | Page : 744-746 |
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| Porokeratosis ptychotropica: A rare manifestation and dermoscopic feature |
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Shan Zhang
From the Department of Dermatology, Wenzhou Hospital of Integrated Traditional Chinese and Western Medicine, Zhejiang, China
| Date of Web Publication | 23-Feb-2023 |
Correspondence Address:
Shan Zhang
Department of Dermatology, Wenzhou Hospital of Integrated Traditional Chinese and Western Medicine, Zhejiang - 325000
China
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/ijd.ijd_1145_20
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 Abstract | | |
We report a case of porokeratosis ptychotropica with a rare manifestation. Dermoscopy showed dotted vessels, cerebriform pattern, white scales, and brown and greyish white tracks in the periphery over a red-brown background. A skin biopsy confirmed the diagnosis from the presence of cornoid lamellae.
Keywords: Cornoid lamellae, dermoscopy, porokeratosis ptychotropica
How to cite this article:
Zhang S. Porokeratosis ptychotropica: A rare manifestation and dermoscopic feature. Indian J Dermatol 2022;67:744-6 |
| Introduction | |  |
Porokeratosis refers to a group of keratinisation disorders characterized by lesions with keratotic borders corresponding to cornoid lamella in histology. Porokeratosis ptychotropica is a rare form of porokeratosis. Diagnosis is often delayed for many years due to the polymorphic presentation of the lesions. Here, we present a rare manifestation of porokeratosis ptychotropica.
| Case Report | | |
A 55-year-old Chinese man presented with a 10-year history of pruritic rash over the bilateral buttocks. The lesions started appearing as sporadic, pink-to-red, bean-sized papules and later coalesced into verrucous plaques with severe itching, especially in hot climate or during perspiration. Treatment with topical tretinoin cream and urea cream was unresponsive. The patient was otherwise healthy. No significant medical or family history was present.
Physical examination showed multiple red-to-violaceous, well-demarcated, verrucous papules and plaques on the buttocks and extending to the upper thighs symmetrically, accompanied by discrete satellite lesions at the periphery [Figure 1]. Subtle hyperkeratosis could be seen on some lesions. | Figure 1: Multiple red-to-violaceous, well-demarcated, subtle hyperkeratosis, verrucous papules and plaques on the buttocks and upper thighs symmetrically, with discrete satellite lesions at the periphery (a and b)
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Dermoscopic examination exhibited the presence of a brown track with greyish white tracks inside and outside of the track in the periphery [Figure 2]. A few red dotted vessels, cerebriform pattern, and white scales could be seen at the centre over a red-brown background. A punch biopsy of a classic papule on the left buttock revealed epidermal hyperkeratosis, multiple digitate epidermis with columns of parakeratosis in the form of prominent cornoid lamellae, an absent granular layer, acanthosis, and some dyskeratotic keratinocytes [Figure 3]. There was a perivascular lymphocytic inflammatory infiltration and pigment dropout in papillary dermis. | Figure 2: Dermoscopic figure dotted vessels (white circle), cerebriform pattern (black circle), white scales (white arrow), and brown and greyish white tracks at the periphery (black arrow) (× 10, polarized mode, Heine Delta 20T dermatoscope)
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 | Figure 3: Histopathology: Epidermal hyperkeratosis, a digitate epidermis with columns of parakeratosis in the form of prominent cornoid lamellae (black arrow), an absent granular layer, acanthosis, and some dyskeratotic keratinocytes (H and E × 40) (a). Multiple cornoid lamellae (black arrow), a perivascular lymphocytic inflammatory infiltration and pigment dropout in papillary dermis (H and E × 40) (b)
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Based on these findings, the diagnosis of porokeratosis ptychotropica was made. The patient subsequently underwent treatment with oral acitretin 30 mg/d, topical tretinoin cream, and urea cream for two months with little improvement.
| Discussion | | |
Porokeratosis ptychotropica was first reported in 1995 by Lucker et al.[1] and was described as a rare variant of porokeratosis involving body folds, particularly the intergluteal cleft. The concept of this entity later evolved and now refers to the eruption composed of symmetrical pruritic verrucous, hyperkeratotic or psoriasiform lesions localised to the perinatal cleft, buttocks, upper thighs, and the genitalia in a butterfly fashion with peripheral satellite lesions. The growth is often slow. Porokeratosis ptychotropica mainly affects immunocompetent middle-aged men, or rarely immunocompromised old women.[2],[3] The aetiology and pathogenesis of porokeratosis ptychotropica still remains unclear. Family history is often negative. Only one familial case of two brothers was reported by Takiguchi RH et al.[4] It can coexist with other types of porokeratosis, including porokeratosis of Mibelli,[5] linear porokeratosis, and disseminated superficial actinic porokeratosis.[3] A similar mechanism may exist. To note, there are multiple alternative descriptions in published literatures of porokeratosis ptychotropica, such as hyperkeratotic porokeratosis, genitogluteal porokeratosis, verrucous porokeratosis, and seborrheic keratosis-like porokeratosis. These terminologies are not uniform and some might be a subset of porokeratosis of Mibelli.
Cornoid lamellae, a diminished or absent granular layer, as well as dyskeratotic cells are characteristic histological features of porokeratosis. Some authors suggest that multiple cornoid lamellae throughout the lesion is a classic feature of porokeratosis ptychotropica. But this histological finding did not show in the case of porokeratosis ptychotropica in psoriasis form,[6] and other types of porokeratosis with verrucous appearance could also reveal multiple cornoid lamellae.[3],[7] As a result, we propose that the number and distribution of cornoid lamellae are more relative with the morphology of the lesions rather than the type. Other histological findings including vacuolated basal layer, inflammatory infiltration in the dermis, incontinence of pigment, and dilated papillary dermal blood vessels can also be found in some cases. Besides, the histology of central lesions might be nonspecific, so the periphery seems to be the ideal location for biopsy if the diagnosis of porokeratosis is considered.[6],[8] In our case, though it was a rare manifestation presenting as a red-to-violaceous papular form with little scales, we still classified it as porokeratosis ptychotropica according to the hereditary trait, onset age, sex, the classical symptom of pruritus, distribution of lesions, and the histopathological feature of cornoid lamellae.
Dermoscopic examination can be used for differential diagnosis and early detection of malignant transformation. The dermoscopic description of porokeratosis ptychotropica has been seldom reported, and it is somewhat different from our case: the rosette sign and central scar-like area could be found.[9] In our case, it should be differentiated from verruca, seborrheic keratosis, and lichen planus. In dermoscopy, verruca generally presents as “even-colored light brown to yellow patch with dots or globular vessels”.[10] Typical findings like comedo-like openings, milia-like cysts, and hairpin vessels can be seen in seborrheic keratosis. Wickham striae is specific for lichen planus. As for our case, the hyperkeratotic border, the hallmark of porokeratosis, clinically indistinguishable and appearing as peripheral brown and greyish white tracks in dermoscopy, can make a difference and guide the bioptic sampling.
The therapy of porokeratosis is usually refractory and easy to relapse. Conventional treatments including oral and topical retinoids, vitamin D analogues, corticosteroids, 5-fluorouracil, 5% imiquimod, and cryotherapy showed minimal or variable effects. Surgery seems to be the only method that leads to a satisfactory result, but it is not advisable in extensive lesions like porokeratosis ptychotropica. Recently, Fustà-Novell et al.[11] reported the application of photodynamic therapy in porokeratosis ptychotropica with symptomatic relief and clinical improvement: this seems to be a promising therapeutic option. In view of the risk of malignant transformation,[2] early detection and long-term follow-up are still necessary.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Acknowledgements
Thanks are due to Deren Fang from Department of Dermatology, The First Affiliated Hospital, College of Medicine, Zhejiang University for offering the partial clinical data of the patient.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Lucker GP, Happle R, Steijlen PM. An unusual case of porokeratosis involving the natal cleft: Porokeratosis ptychotropica? Br J Dermatol 1995;132:150-1.  |
| 2. | Mazori DR, Shvartsbeyn M, Meehan SA, Tarsis SL. Transformation of porokeratosis ptychotropica into invasive squamous cell carcinoma. Int J Dermatol 2017;56:679-80. |
| 3. | Murase J, Gilliam AC. Disseminated superficial actinic porokeratosis co-existing with linear and verrucous porokeratosis in an elderly woman: Update on the genetics and clinical expression of porokeratosis. J A Acad Dermatol 2010;63:886-91. |
| 4. | Takiguchi RH, White KP, White CR Jr, Simpson EL. Verrucous porokeratosis of the gluteal cleft (porokeratosis ptychotropica): A rare disorder easily misdiagnosed. J Cutan Pathol 2010;37:802-7. |
| 5. | Ma Y, Li C, Wu J, Cui P, Lin L, Feng S. Coexistence of porokeratosis ptychotropica with porokeratosis of Mibelli in a Chinese man. Postepy Dermatol Alergol 2015;32:307-9. |
| 6. | Kawakami Y, Mitsui S. A case of porokeratosis ptychotropica: Successful treatment with topical 5% imiquimod cream. Clin Exp Dermatol 2017;42:839-41. |
| 7. | Caseiro Silverio P, Pham XC, Kaya G. Porokeratoma: A possible association with human papillomavirus infection. Dermatopathology (Basel) 2015;2:43-5. |
| 8. | Malek J, Chedraoui A, Kibbi AG, Ghosn S. Genitogluteal porokeratosis: 10 Years to make the diagnosis! Am J Dermatopathol 2009;31:604-6. |
| 9. | Luo Y, Liu J. Image Gallery: Verrucous porokeratosis with characteristic histopathological and dermoscopic features. Br J Dermatol 2017;176:e38. |
| 10. | Kim WJ, Lee MK, Song M, et al. Clinical clues for differential diagnosis between verruca plana and verruca plana-like seborrheic keratosis. J Dermatol 2015;42:373-7. |
| 11. | Fustà-Novell X, Podlipnik S, Combalia A, Morgado-Carrasco D, Ferrando J, Mascaró JM Jr, et al. Porokeratosis ptychotropica responding to photodynamic therapy: An alternative treatment for a refractory disease. Photodermatol Photoimmunol Photomed 2017;33:271-4. |
[Figure 1], [Figure 2], [Figure 3] |
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