Linear porokeratosis of Mibelli and DSAP

Linear porokeratosis and disseminated superficial actinic porokeratosis (DSAP) are clinical variants of porokeratosis. We report the rare coexistence of these two variants. Porokeratosis is a genodermatosis which has at least five different clinical variants; Mibelli, linear, DSAP, plantaris palmaris et disseminata, and punctate (Wade & Ackerman, 1980). All of these manifest the distinctive peripheral keratotic ridge which histologically corresponds to the cornuid lamella. Although lesions of porokeratosis of Mibelli and linear porokeratosis are sometimes seen together in individuals, the coexistence of other porokeratotic variants is rare.     

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.     

Disseminated superficial actinic porokeratosis. Coexistence with other porokeratotic variants

The coexistence of disseminated superficial actinic porokeratosis (DSAP) with other variants of porokeratosis is rare. We report three such cases: DSAP with porokeratosis of Mibelli; DSAP with linear porokeratosis; and DSAP occurring in the mother of a girl with linear porokeratosis. Although different areas of skin and different family members usually express the same morphological variant, we suggest that the simultaneous expression of two closely linked gene loci could explain the coexistence of different porokeratotic variants.     

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.     

Punctuate porokeratotic keratoderma

Two unrelated patients had numerous palmoplantar "music box spine" keratotic plugs and pits of 11 and 13 years' duration. Histologic examination revealed a compact column of parakeratosis resembling that of a cornoid lamella of porokeratotic conditions. Ultrastructurally in clinically affected skin, the stratum corneum contained numerous variable-sized pyknotic nuclei, and cells in the stratum granulosum contained fewer keratohyalin granules. The ultrastructural findings differed from those of porokeratosis of Mibelli and disseminated superficial actinic porokeratosis. The proper nosologic designation should be punctuate porokeratotic keratoderma.     

Porokeratotic palmoplantar keratoderma discreta a new entity or a variant of porokeratosis plantaris discreta?

We report a family with hyperkeratotic lesions on palms and soles. The lesions became evident in the second to third decade, and there is an autosomal dominant mode of transmission. Skin biopsy specimens show a central epidermal depression filled by a compact hyperkeratotic plug of columnar parakeratosis, like a broad cornoid lamella. The lesions resemble porokeratosis plantaris discreta clinically and histologically. The cornoid lamella is a broad, solid keratin plug rather than a centrifugally enlarging annular or serpentine ridge as can been seen in other types of porokeratosis. Perhaps the lesions of porokeratosis plantaris discreta should not be classified as a true porokeratosis but as porokeratotic plantar keratoderma discreta. We have therefore called the lesions in our patients porokeratotic palmoplantar keraiodcrma discreta, and suggest that porokeratotic palmoplanfar keratoderma discreta is a variant of porokeratosis plan taris discreta.     

The successful off-label use of photodynamic therapy for classic porokeratosis of Mibelli: case report

Porokeratosis of Mibelli is an uncommon chronic disorder of epidermal keratinization that should be treated because it can undergo malignant change into epithelial tumors on the lesions. At the moment, it represents a therapeutic challenge for dermatologists because of the lack of standardized guidelines about the treatment. Herein, we report a case of classic porokeratosis of Mibelli treated with photodynamic therapy successfully.     

Punctate Porokeratosis. A Clinical Variant of Porokeratosis of Mibelli

Punctate porokeratosis is not usually recognized as a clinical form of porokeratosis of Mibelli. Two cases of punctate porokeratosis are presented. Other punctate lesions with similar clinical features which should be considered in the differential diagnosis are discussed.     

Etretinate treatment in disseminated porokeratosis

A 77-year-old man with disseminated superficial porokeratosis of Mibelli (PM) over the whole body surface for 60 years was treated with oral etretinate (1 mg/kg/day) for nine months after resection of two lesions of Bowen's disease. Clinically, hyperkeratotic plaques were flattened after three months of treatment. Histological changes included disappearance of parakeratosis and residual but less stacked cornoid lamella. Etretinate may be the first choice of treatment in widespread porokeratosis.     

Focal porokeratosis of nuchae: case report

Porokeratosis is the common name of several diseases of unknown pathogenesis, which are similar in clinical appearance. It was first described in 1893 and was thought to be a disorder of sweat glands, hence the name porokeratosis. The lesion that can be found in all cases is annular, with atrophic center, and hyperkeratotic outer ring. Cases of porokeratosis have been linked with genetic heritage, excessive ultraviolet exposure, kidney failure, and state of immunosuppression, but no definitive link has been established. As a rare condition, its main feature is that the correct diagnosis can be delayed for a significant period of time. Porokeratotic lesions have a high incidence of malignant transformation and are considered premalignant. We present a case where a porokeratotic lesion was unsuccessfully treated as a psoriatic lesion for more than a year in a patient with previously diagnosed psoriasis. A skin biopsy was performed at our department, which revealed classic cornoid lamella and thus led to the correct diagnosis. The lesion was excised. Additional diagnostic tests revealed normal kidney function and intact immune system. A follow-up protocol was established for the patient, ensuring timely diagnosis of any future porokeratotic lesions. Porokeratosis, especially when there are only few lesions, is not difficult to manage - once it is diagnosed. A diagnosis of porokeratosis may also aid in identifying a serious systemic disease such as kidney failure. Importantly, a misdiagnosis of porokeratosis may lead to development of skin cancer.     

Linear porokeratosis with multiple squamous cell carcinomas successfully treated by electrochemotherapy

Porokeratosis is a clonal epidermal disorder of keratinization characterized by annular lesions with an atrophic centre and a hyperkeratotic edge. The cornoid lamella is the histopathological hallmark. Six clinical variants are recognized: porokeratosis of Mibelli; disseminated superficial porokeratosis; disseminated superficial actinic porokeratosis (DSAP); porokeratosis plantaris et palmaris disseminata; punctate porokeratosis and linear porokeratosis. Linear porokeratosis is the type most frequently associated with malignant transformation into squamous cell carcinoma (SCC). It is thought to represent a mosaic form of DSAP and has an incidence of less than 1 in 200 000; treatment options are limited. We describe a patient with systematized linear porokeratosis and multiple SCCs who was successfully treated with bleomycin electrochemotherapy (ECT), a form of intralesional chemotherapy. In view of their large number, the individual SCCs were treated with bleomycin ECT. One year post‐treatment the patient remains tumour free. To our knowledge, this is the first case of multiple SCCs treated by ECT in the context of systematized linear porokeratosis. Our case highlights the challenges associated with diagnosing and managing this unusual form of porokeratosis.     

Q开关532nm激光治疗浅表播散性汗孔角化症一例

报告Q开关532 nm激光成功治疗1例浅表播散性汗孔角化症。患者,女,49岁。颜面部弥漫分布大小不等浅褐色斑疹,中心色淡略凹陷,边缘隆起,似黑圈状损害。皮损组织病理检查诊断为汗孔角化症。经Q开关532 nm激光治疗2次,皮损大部分消退,取得较好效果。     

Etretinate in the Treatment of Disseminated Porokeratosis of Mibelli

A 30-year-old man with disseminated porokeratosis of Mibelli (DPKM) was treated with oral etretinate. The dose ranged between 75 mg/day and 50 mg/day for 21 weeks. An improvement of the lesions was observed, especially of very painful verrucous plaques of the left shin. No serious side effect was seen. The patient, who had been incapacitated, is now able to work. The benefit of long-term therapy of etretinate should be considered against its side effects.     

Porokeratosis of Mibelli with underlying hemangioma treated by the flashlamp-pumped pulsed dye laser

Porokeratosis of Mibelli is a disorder of epidermal proliferation in which an abnormal clone of cells expands in a centrifugal manner. We present a case of porokeratosis of Mibelli with an underlying hemangioma that was treated with a 585 nm flashlamp-pumped pulsed dye laser. The underlying hemangioma responded well to laser therapy while the porokeratosis remained unchanged. The implications of this for the pathogenesis of porokeratosis and the specificity of the pulsed dye laser are discussed.     

Linear porokeratosis superimposed on disseminated superficial actinic porokeratosis: report of two cases exemplifying the concept of type 2 segmental manifestation of autosomal dominant skin disorders.

A concept of dichotomous types of segmental involvement of autosomal dominant skin disorders has recently been proposed. Among the different types of porokeratosis, disseminated superficial actinic porokeratosis is known to be an autosomal dominant skin disorder, and linear porokeratosis represents the segmental form of the disease. We intended to exemplify the type 2 segmental manifestation within this concept. Clinical and histopathologic aspects of porokeratotic lesions of 2 patients were investigated. The family history was studied in both cases. Linear porokeratosis superimposed on disseminated superficial actinic porokeratosis was observed in both patients. These 2 cases of linear porokeratosis associated with disseminated superficial actinic porokeratosis can be taken as further examples of a type 2 segmental involvement occurring in an autosomal dominant skin disorder.     

Exacerbation of porokeratosis during etretinate therapy

Four patients with disseminated superficial porokeratosis (DSP) were treated with the oral aromatic retinoid etretinate. Using the standard dosage of 1 mg/kg/day, 3 patients showed exacerbation of cutaneous lesions 4-6 weeks after initiation of treatment. Because of additional severe generalized itching and discomfort in all patients, treatment had to be discontinued. The clinical exacerbation correlated with a significant increase in the lymphohistiocytic dermal infiltrate beneath the cornoid lamella. In our experience the use of etretinate triggered the exacerbation of porokeratotic lesions with associated side effects showing that their use is not necessarily of benefit as previously reported.     

Porokeratosis of Mibelli on the penis, scrotum and natal cleft

Genital porokeratosis of Mibelli is rare. We report a patient with lesions affecting the penis, scrotum and natal cleft and discuss the aetiology, clinical presentation and treatment of the condition.     

Verrucous porokeratosis of Mibelli on the buttocks mimicking psoriasis

The typical presentation of porokeratosis of Mibelli is of a solitary plaque with a prominent raised border cleaved by a central furrow. The central portion of the plaque is usually slightly atrophic. The plaques vary in size from a few millimeters to several centimeters in diameter and tend to be acrally distributed, though they can occur on any part of the body. We report an unusual case of verrucous porokeratosis of Mibelli, localized to the natal cleft, that mimicked psoriasis. This entity, though unusual, is not unique. Two similar cases of verrucous porokeratosis of Mibelli limited to the natal cleft region and resembling psoriasis have been reported in the British literature. Verrucous porokeratosis of Mibelli localized to the natal cleft appears to be a distinct clinical entity that can mimic psoriasis. Better recognition of this form of porokeratosis of Mibelli may result in earlier diagnosis and initiation of appropriate therapy.     

Porokeratosis of Mibelli induced by topical corticosteroid

BACKGROUND: [corrected] Prorokeratosis of Mibelli is a chronic disorder characterised by slightly atrophic plaques surrounded by keratotic border. METHODS AND RESULTS: A 45-year-old with clobetazole propionate ointment for psoriasis over 15 years developed characteristic lesions of porokeratosis Mibelli on the elbows. Histopathological examination revealed the cornoid lamellae located on the edges of the specimen and psoriasiform acanthosis and a spongiotic pustule formation in the center of the specimen; thus, it was suggested as 'psoriasis encircled by porokeratosis'. CONCLUSIONS: Development of porokeratosis may be explained by the local immunosuppressive effect of the prolonged application of the topical steroid.     

Eruptive Pruritic Papular Porokeratosis

Three cases of an unusual variant of porokeratosis (Mibelli) were described. Patients with disseminated superficial porokeratosis for some years suddenly developed intensively pruritic erythematous papules. Skin biopsies revealed that these papules contained cornoid lamellae on their tops. Pruritic papules subsided in several months, leaving slightly hyperkeratotic brown annular lesions which were shown to contain typical cornoid lamellae histopathologically. This type of porokeratosis has not been reported in the literature.