Eruptive pruritic papular porokeratosis: a pruritic variant of porokeratosis

Porokeratosis is a chronic skin disorder characterized clinically by the presence of crater-like patches with an elevated thick keratotic border and central atrophy. Histology reveals cornoid lamellae. While porokeratosis is practically asymptomatic, a pruritic variant has been reported. We recently encountered an 82-year-old man with pruritic porokeratosis. He presented with erythematous papules and intensively itchy patches on his lower limbs that had been present for 6 months. Histopathological examination revealed the characteristic cornoid lamellae. We describe this case in detail and provide a review of the published work.     

生殖器及肛周发疹性瘙痒性兵疹性汗孔角化病1例

报告1例局限于生殖器及肛周的发疹性瘙痒性丘疹性汗孔角化病。患者男性,41岁。阴茎汗孔角化病10年后,在阴囊、肛周出现瘙痒剧烈的红色斑丘疹。皮肤活检显示丘疹的边缘隆起处有角化不全鸡眼样板。     

Cornoid lamellae associated with follicular infundibulum and acrosyringium in porokeratosis

Skin lesions of porokeratosis consist of an atrophic center bordered by a peripheral grooved keratotic ridge that corresponds histopathologically to the cornoid lamella. Originally porokeratosis was named based on the assumption that the columns of parakeratosis emerge from the ostia of eccrine ducts. Despite this, it is generally accepted that the cornoid lamellae are rarely related to the acrosyringium. We recently encountered two cases of porokeratosis, where the cornoid lamellae were related to the follicular infundibulums. Therefore, we analyzed the location of the cornoid lamellae in 86 lesions of porokeratosis from 73 patients from our archives. We found that many cornoid lamellae are also detected at follicular infundibulum and acrosyringium. The existence of so many cornoid lamellae at follicular infundibulum and acrosyringium inside the plaques cannot be explained by pure coincidence and may be more than fortuitous.     

Unilateral punctate porokeratosis - Case report

This case report involves a 20-year-old man with unilateral punctate porokeratosis. The patient presented an 8-year history of numerous asymptomatic keratotic papules and pits with linear distribution on his left pal-mar surface and fifth finger of the left hand. Histopathological examination of the keratotic plug revealed findings of distinct epidermal depressions containing cornoid lamellae. This report review draws attention to differential diagnoses of punctate porokeratosis.     

Genitogluteal porokeratosis involving the scrotum: an unusual presentation of an uncommon disease

Porokeratosis represents a heterogeneous group of keratinization disorders typified by the presence of annular plaques with distinct, raised borders that include cornoid lamellae. Histopathologically, a cornoid lamella is a column of parakeratotic scale overlying an epidermal invagination that displays nearby dyskeratotic keratinocytes and loss of the granular layer. Porokeratosis ptychotropica constitutes a rare variant that classically presents as a plaque in the gluteal cleft that mimics a dermatitis and microscopically contains numerous cornoid lamellae. We report a 28 year-old man with a two-month history of scrotal burning and itching associated with the development of multiple thin red plaques with distinct elevated borders and a pebbled appearance. Histopathological examination revealed psoriasiform acanthosis and multiple cornoid lamellae, which is consistent with a diagnosis of porokeratosis ptychotropica. Our patient's presentation may represent a distinct variant with clinical features of verrucous porokeratosis and histopathological features of porokeratosis ptychotropica which may suggest that the finding of multiple cornoid lamellae is not unique to porokeratosis ptychotropica.     

Immunohistochemical Detection of p53 Tumor Suppressor Protein in Porokeratosis

We examined 9 Japanese cases of porokeratosis (4 of the plaque type, 2 of disseminated superficial actinic porokeratosis, 2 of disseminated superficial porokeratosis, and one of giant porokeratosis) for the expression of p53 tumor suppressor protein immunohistochemically, using two anti-p53 antibodies, CM1 and DO1. The same results were obtained with both antibodies. The epidermis central to the cornoid lamellae was positive in 8 of 9 specimens. On the other hand, the peripheral epidermis was positive in 2 of the 9 cases. The epidermis beneath the cornoid lamellae was positive in 3 of the 9 cases. The frequency of p53 positivity was significantly higher in the epidermis central to cornoid lamellae over that beneath or peripheral to them (Fisher's exact probability test, p<0.05). The majority of squamous cell carcinoma cells arising on giant porokeratosis stained with CM1 and DO1. These data may suggest that the abnormal p53 expression has some relevance to the skin carcinogenesis of porokeratosis.     

Generalized Eruptive Porokeratosis of Mibelli with Associated Psoriasis

A case of eruptive porokeratosis of Mibelli with diverse morphologic features, including circinate macular, circinate plaque and verrucous varieties is presented. No matter how variable the clinical presentation may be, the histologic hallmark of porokeratosis, the cornoid lamellae, is always present. The cornoid lamellae vary in height in relation to how prominent the thready ridge of the clinical lesion appears. Our patient also had psoriasis which initially masked the porokeratotic lesions both clinically and histologically. Awareness of the various clinical expressions of porokeratosis of Mibelli would 1) make unnecessary the segregation of certain forms of porokeratosis into separate entities, and 2) help in the recognition of less classical forms of porokeratosis.     

Follicular Porokeratosis at alae Nasi; A Case Report and Short Review of Literature

Porokeratosis are disorders of keratinization, characterized histologically by a parakeratotic column, the cornoid lamellae, and clinically by a distinct peripheral ridge. Porokeratosis usually occurs on the trunk or extremities, and facial lesions are rare. Follicular involvement, identified by follicular localization of cornoid lamellae, is uncommon and described only in association with disseminated superficial actinic porokeratosis (DSAP) and porokeratosis Mibelli (PM). A 34-Year- old woman is presented with asymptomatic 1 cm plaque lesion with hyperkeratotic ridge and depressed center on her nose since three years. Histopathological examination of a biopsy revealed cornoid lamellae confined exclusively to the follicle.     

伴炎症反应的汗孔角化病三例

汗管角化症是一种少见的慢性角化性皮肤病,以中央轻度萎缩边缘堤状角质嵴围绕的皮损为特征。组织病理学特征为角样板层。本病一般无临床症状,但伴明显瘙痒的汗孔角化症已经有文献报告,并被命名为“发疹性瘙痒性丘疹型汗管角化症”或“处于炎症反应期的DSP”。笔者近期诊断三例这样的病患并推荐使用“发疹性瘙痒性丘疹型汗管角化症”来命名这一特殊类型的汗孔角化症。     

Premature apoptosis of keratinocytes and the dysregulation of keratinization in porokeratosis

BACKGROUND: Porokeratosis is a dyskeratotic disorder of the skin characterized by cornoid lamella with parakeratosis, hyperkeratosis and loss of granular layers. The pathogenesis of porokeratosis and the mechanism(s) of its abnormal keratinization are still unknown. OBJECTIVE: To elucidate the mechanism(s) of abnormal keratinization that leads to the formation of cornoid lamellae in porokeratosis. METHODS: Apoptosis of keratinocytes was assessed in the skin of seven patients by an in situ apoptosis assay based on the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL) reaction. Patterns of loricrin and involucrin expression were examined by immunohistochemistry. RESULTS: TUNEL-positive keratinocytes were observed in the epidermis underlying the cornoid lamella in all cases examined. Furthermore, loricrin expression was interrupted there, in contrast to involucrin, which was expressed diffusely in the lesional epidermis. CONCLUSIONS: These results suggest that an abnormal early keratinocyte apoptosis accompanied by dysregulation of terminal differentiation of those cells may be involved in the pathogenesis of porokeratosis.     

Follicular porokeratosis: distinct clinical entity or histologic variant?

Various clinical subtypes of porokeratosis, clinically characterized by annular plaques with a normal or atrophic center and a distinctive keratotic ridge, are described based on the age of onset, size, number and distribution of the lesions. Follicular involvement, identified by follicular localization of cornoid lamellae, is uncommon and has only been reported in association with other subtypes such as disseminated superficial actinic porokeratosis and porokeratosis of Mibelli. We present a case of follicular porokeratosis in a 40-year-old male who presented initially with scaly red "papules" in a follicular distribution on the upper extremity. Microscopic examination of a punch biopsy specimen revealed parakeratosis confined to the follicle and mild interface change. A repeat biopsy performed in 2008 revealed identical histologic features. In terms of etiopathogenesis, a clone of cells at the base of the follicle demonstrating abnormal keratinization is not a novel concept and has been demonstrated in other porokeratotic dermatoses. However, the presence of lesions that are solely follicular based, in terms of clinical presentation and histologic findings, and static over a 3-year period favors the concept that follicular porokeratosis is a distinct clinical entity and not merely a histologic variant of the porokeratotic dermatoses described in the literature thus far.     

A case of the hyperkeratotic variant of porokeratosis Mibelli

Herein, we report a case of the hyperkeratotic variant of porokeratosis Mibelli. A 58-year-old woman presented with two brownish verrucous plaques on the buttock for 20 years, and extremely hyperkeratotic verrucous nodules and brownish macules on the right foot for 1 year. Histopathological findings of the buttock were typical of porokeratosis. However, histopathological findings of the right foot were atypical for porokeratosis, including extreme hyperkeratosis and an increased number of and unusual sized cornoid lamellae.     

Reticulated porokeratosis. A unique variant of porokeratosis

A young man presented with a chronic, persistent reticulated dermatosis involving the groin, genitals, and thighs that was refractory to therapy. Biopsy specimen revealed multiple cornoid lamellae consistent with porokeratosis. This clinical appearance has not been previously described, to our knowledge. The other clinical forms of porokeratosis and their histology are briefly reviewed.     

Solar facial porokeratosis

Porokeratosis is comprised of a heterogeneous group of disorders that are inherited in autosomally dominant fashion. It has a wide variety of manifestations. In the last ten years, we have treated cases of porokeratosis that don't fit into the well known categories of porokeratosis. For this reason, the present study was carried out. This study included 15 cases whose ages ranged from 19-37 years with a mean +/- SD of 26.93 +/- 4.52. There were 12 females and 3 males. The duration of the disease ranged from 1-10 years with a mean +/- SD of 4 +/- 2.85 years. Their lesions were located only on the face, mostly on the distal part of the nose and the surrounding perinasal area. The number of lesions on each patient ranged from 1-15, with a mean +/- SD of 4.73 +/- 4.35. The morphology of these lesions consisted of papules with a size range from 0.1-1 cm and a warty appearance. They were skin colored and surrounded by a keratotic rim in the form of a collar. The histopathology showed the picture of porokeratosis with cornoid lamellae and additional features characteristic of this disease. We concluded that facial solar porokeratosis is a variant of porokeratosis and is a disease of the nose of young females with a characteristic clinical and histopathological picture.     

Pustular porokeratosis

We report a case of disseminated superficial actinic porokeratosis (DSAP) with neutrophilic pustules within cornoid lamellae on histopathologic examination, corresponding to pustules along the elevated rim clinically as well. A review of the literature identified only one other case in which pustules have been associated with porokeratosis. Our case represents an unusual variant of DSAP, which may make an ordinarily straightforward clinical diagnosis more challenging.     

Porokeratosis ptychotropica: a lesser‐known variant

We report a case of the rare porokeratosis variant porokeratosis ptychotropica (PP). A circumferential perianal plaque and the characteristic histology of multiple cornoid lamellae with underlying dermal amyloid deposition were seen. Amyloid deposition was seen in the biopsied intertriginous area of the plaque only, which, in concordance with other cutaneous amyloid deposition disorders, may suggest a role for friction in the pathogenesis of this histological finding. We review the literature on PP and summarize the poor response seen to treatments.     

Squamous cell carcinoma arising from lesions of porokeratosis palmaris et plantaris disseminata

We report a 63-year-old Japanese man with numerous hyperkeratotic papules of porokeratosis palmaris et plantaris disseminata (PPPD) who developed multiple squamous cell carcinomas on the lesional sites of the palms and soles. The hyperkeratotic papules, which showed tightly packed columns of parakeratotic cells in the cornified layer (cornoid lamella), lost granular layer, and dyskeratotic keratinocytes in the epidermis below the cornoid lamella histologically, had been noticed on the palms and soles from the age of 28 and 43, respectively. He has no family history of such hyperkeratotic papules. Treatment with etretinate (10-50 mg/day) was given discontinuously, and the total dose of etretinate amounted to approximately 21 g over 14 years (average: 0.07 mg/kg/day). He noticed erosions on the hyperkeratotic papules on the left sole and palm more than 9 months after cessation of treatment with etretinate. Histological findings showed numerous atypical keratinocytes in the epidermis and upper dermis with mononuclear cell infiltration seen in the upper dermis. The diagnosis of squamous cell carcinoma arising from the lesions of porokeratosis palmaris et plantaris was made. Five erosions with histologically malignant changes were removed 1 cm from the margin of the erosions. These findings suggest that etretinate may have an inhibitory action on malignant changes in PPPD.     

Multiple keratotic papules on palm

Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is a rare nonhereditary malformation of the eccrine duct. A relationship with linear porokeratosis is not yet established; some consider it as a rare variant of porokeratosis involving the acrosyringium, whereas others consider it a separate entity based on distinctive clinical features and histologic accentuation within ostial structures. A 7-year-old girl presented with multiple asymptomatic keratotic papules over her right palm, present since the age of 6 months. These papules were arranged in a linear distribution over the palm and middle finger of the right hand. Most of the papules were discrete. However, lesions on the middle finger coalesced to form a plaque. Histology revealed a keratin filled deep invagination of the epidermis, notable for a column of parakeratosis ("cornoid lamella"). The dermis was notable for dilated eccrine ducts and absent inflammation. Considering the clinical and histological evidence, a diagnosis of PEODDN was made. Its clinical resemblance to linear lichen planus and linear porokeratosis is discussed. Also, we provide a brief review of this rare condition.