10.5826/dpc.1401a17
text/xml
2160-9381
3386
en
Mohamed Denguezli
https://creativecommons.org/licenses/by-nc/4.0
Dermatology Practical & Conceptual
histopathology 
A Rare Case of Follicular Porokeratosis Ptychotropica: When Dermoscopy Enghlitens Clinics 
Text.Serial.Journal
https://dpcj.org/index.php/dpc
Research Letter
2024-01-31
2023-04-06
2024-01-31
2024-02-21
e2024017
Dermatol Pract Concept
Mohamed Denguezli
2024/01/31
10.5826/dpc.1401a17
e2024017
Dermatology department, Farhat Hached Hospital, Sousse, Tunisia 
2160-9381
histopathology 
en
e2024017
Zhao M, Sanusi T, Zhao Y, Huang C, Chen S. Porokeratosis with follicular involvement: report of three cases and review of literatures. Int J Clin Exp Pathol. 2015;8(4):4248-4252. PMID: 26097620. PMCID: PMC4467007.
A Rare Case of Follicular Porokeratosis Ptychotropica: When Dermoscopy Enghlitens Clinics 
https://dpcj.org/index.php/dpc/article/download/3386/2453
      A Rare Case of Follicular Porokeratosis
Ptychotropica: When Dermoscopy Enghlitens Clinics
           Nour El Imene Ouni1, Sana Mokni1, Nadia Ghariani Fetoui1, Jacem Rouatbi1,
            Marouen Ben kahla1, Maha Lahouel1, Amina Aounallah1 Najet Ghariani1,
                 Badreddine Sriha2, Colandane Belajouza1, Mohamed Denguezli1


1 Dermatology department, Faculty of Medicine of Sousse, University of Sousse, Farhat Hached Hospital, Sousse, Tunisia
2 Anatomopathology Department, Faculty of Medicine of Sousse, University of Sousse, Farhat Hached Hospital, Sousse, Tunisia



Key words: Porokeratosis ptychotropica, follicular involvement, dermoscopy, histopathology
Citation: Ouni NI, Mokni S, Ghariani Fetoui N, et al. A Rare Case of Follicular Porokeratosis Ptychotropica: When Dermoscopy
Enghlitens Clinics. Dermatol Pract Concept. 2024;14(1):e2024017. DOI: https://doi.org/10.5826/dpc.1401a17
Accepted: June 23, 2023; Published: January 2024
Copyright: ©2024 Ouni et al. This is an open-access article distributed under the terms of the Creative Commons Attribution-
NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use,
distribution, and reproduction in any medium, provided the original authors and source are credited.
Funding: None.
Competing Interests: None.
Authorship: All authors have contributed significantly to this publication.
Corresponding Author: Dr Ouni Nour el Imene, M.D, Farhat Hached Hospital, University of Medicine, Sousse, Tunisia.
Tel: +21624041144 Email: nourelimene286@gmail.com




Introduction                                                             history revealed no similar lesions. Physical examination
                                                                         noted well-demarcated, red–brown and verrucous plaques
Porokeratosis is an epidermal keratinization disorder                    located on both buttocks with satellite hyperkeratotic, pap-
­characterized clinically by annular plaques with keratotic              ules (Figure 1A). Dermoscopy showed a raised scaly rim,
ridge and an atrophic center. Several variants have been                 limiting a non-atrophic center, gray-brown dots, and pig-
described [1]. Porokeratosis ptychotropica (PP) has been                 mentation along the keratin rim (Figure 1B). Interestingly,
recently individualized as a new variant [2]. It is charac-              we noted prominent follicular plugging and follicular spic-
terized by verrucous plaques localized in the regions of the             ules in 2 lesions (Figure 1, C and D). Multiple polymorphous
buttocks, most commonly the gluteal cleft. Its dermoscopic               vessels are present within the keratin rim as well as periph-
features have been rarely reported [2]. Herein, we describe              eral vascularization adjacent to but outside the keratin rim
a rare case of PP with follicular involvement and particular             (Figure 1, C and D). A skin biopsy specimen showed epi-
­dermoscopic patterns.                                                   dermal hyperplasia, multiple cornoid lamellae in the stratum
                                                                         corneum with an absence of underlying granular zone, and

Case Presentation                                                        dyskeratotic cells in the spinous layer. Slight lymphocytic in-
                                                                         filtration was also seen in the upper dermis. Multiple serial
A 48-year-old man with no particular medical history pre-                sections revealed cornoid lamella involving the follicular in-
sented to our outpatient department with the chief com-                  fundibulum (Figure 2). Based on clinical, dermoscopic, and
plaint of pruritic gluteal lesions evolving for 15 years. Family         histopathological features, the diagnosis of PP with follicular




Research Letter | Dermatol Pract Concept. 2024;14(1):e2024017 ﻿                                                                       1
Figure 1. (A-D) A 48-year-old man with no particular medical history who presented with: (A) Ptychotropic porokeratosis showing well-de-
marcated, red–brown, and verrucous plaques located on both buttocks with satellite roundish, hyperkeratotic, brownish papule. (B) Polarized
dermoscopic image (10X Dermlite DL4) showing a raised scaly rim (black arrow), limiting a non-atrophic center with gray-brown dots and
pigmentation along the keratin rim (red arrow). (C,D) Polarized dermoscopic image (10X Dermlite DL4) showing a cobblestone-like pattern
with prominent keratotic follicular plugs (black arrow) and spicules (blue arrow). Multiple polymorphous peripheral vessels are present
within the keratin rim (red arrow).

involvement was established. The patient was treated with              cornoid lamellae [2]. Dermoscopy is of recognized value in
CO2 laser vaporization for the verrucous lesions. We ob-               assisting the diagnosis of porokeratosis. However, only a
tained the patient’s consent.                                          few cases describe the dermoscopic features of PP [2,3]. The
                                                                       most common dermoscopic patterns, which are not specific

Conclusions                                                            to this variant include a characteristic keratin rim and dotted
                                                                       vessels [2,3]. The peripheral vascularization observed in our
PP is a rare form of porokeratosis. Since its first description        case have been rarely reported in porokeratosis [3]. More-
by Lucker et al in 1995, about 30 cases have been reported             over the keratotic follicular plugs which were present in our
in the literature. Misdiagnosis of PP is common, and differ-           patient have been recently described in only 3 cases: 2 in the
ential diagnosis often includes psoriasis, chronic eczema,             face and one in the scalp [4,5]. It reflects the follicular in-
Bowen disease, dermatophytosis and candidiasis [2]. Histo-             volvement in porokeratosis. In fact, follicular porokeratosis
pathology generally confirms the diagnosis showing multiple            is a newly described variant with less than 20 reported cases,



2                                                                           Research Letter | Dermatol Pract Concept. 2024;14(1):e2024017﻿
                                                                       involvement. We aimed by presenting this case to gain up-to-
                                                                       date knowledge on this rare entity.


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Research Letter | Dermatol Pract Concept. 2024;14(1):e2024017 ﻿                                                                          3
