Lack of TP53 mutations in a case of porokeratosis palmaris, plantaris et disseminata

A 73-year-old man with porokeratosis palmaris, plantaris et disseminata is presented. He had punctate, guttate and annular hyperkeratotic papular lesions widespread on his body with thorn-like hyperkeratosis on the palms and soles. Lesional skin did not show mutations of TP53 exons 5-6, 7, 8.

Disseminated superficial actinic porokeratosis with both typical and prurigo nodularis-like lesions

We report a 50-year-old Korean patient who developed a disseminated superficial actinic porokeratosis (DSAP) with two types of lesions. One was a typical DSAP lesion clinically and histopathologically. The other was clinically similar to prurigo nodularis, but histologic examination showed the findings of porokeratosis such as cornoid lamellae and loss of the granular layer in addition to those of chronic lichenified dermatitis, so it could be described as prurigo nodularis-like porokeratosis. The nodular lesions seemed to develop on preexisting typical lesions of DSAP mainly during the summer by the aggravation of pruritic symptoms and scratching associated with sun exposure. Although we could not find any published reports describing lesions like those of our case, we think that such prurigo nodularis-like porokeratosis can develop in patients with DSAP in some situations involving pruritus and scratching.

Coexistence of disseminated superficial porokeratosis in childhood with congenital linear porokeratosis

Porokeratosis is a genodermatosis characterized by abnormal epidermal keratinization with the histologic finding of cornoid lamella. To date, five clinical variants have been identified. However, the coexistence of these variants in a single patient has been described only rarely. We report a 5-year-old girl with the simultaneous occurrence of porokeratotic lesions in linear and disseminated patterns. Linear lesions were detected at birth and the disseminated lesions developed at the age of 3 years. Histologically the lesions had cornoid lamella, which is typical of this condition.

An unusual presentation of dermatomyositis: the type Wong variant revisited

We describe a 53-year-old white woman with dermatomyositis (DM) who had additional clinical findings of pityriasis rubra pilaris (type Wong dermatomyositis) with histopathologic features of both pityriasis rubra pilaris (PRP) and porokeratosis. Type Wong dermatomyositis was originally described in 11 patients by Wong in 1969 and has been reported in 5 additional patients. This is a rarely described phenomenon in which patients with DM develop cutaneous hyperkeratotic lesions that resemble PRP and histologically show follicular hyperkeratosis and hair follicle destruction. Arrector pilorum muscles also show degenerative findings and myositis. We believe that this is the first reported case of a patient with type Wong DM who also has clinical and histologic features suggestive of porokeratosis. This is important because of the association of adult-onset dermatomyositis with internal malignancy and the well-documented association of porokeratosis with immunosuppression. These clinical and histologic findings serve as markers for malignancy in patients with DM. These patients warrant a complete review of systems and investigation for age-appropriate neoplasms as well as close long-term follow-up by dermatologists to ensure that these cutaneous eruptions are not overlooked.

Synchronous development of disseminated superficial porokeratosis and hepatitis C virus-related hepatocellular carcinoma

Immunosuppression and transplantation have been reported to induce porokeratosis (PK), especially its variant, disseminated superficial PK (DSP). On the other hand, there is ample evidence of a relationship between hepatitis C virus (HCV) infection, liver cirrhosis (LC), and hepatocellular carcinoma (HCC). We report 3 cases of DSP in which the outbreak of DSP was suspected to have occurred during the development of HCC in patients with HCV-positive LC. The patients had undergone ultrasonographic study regularly, and no signs of malignancy had been found before the development of DSP. Their outbreaks of DSP were very acute, and the period between the development of DSP and diagnosis of HCC ranged from 2 to 6 months. The association of HCV-related HCC and DSP has never been previously reported. HCV-induced immunomodulation or its effect on the p53 system may be the basis for this type of association. It is necessary to consider development of HCC whenever DSP is found in HCV-positive patients. DSP may be a new paraneoplastic dermadrome.

Ulcerative porokeratosis

A 54-year-old man presented with multiple annular plaques since infancy. During the intake of nifedipine and nitroglycerin over a period of 6 years, reddish, eruptive and ulcerative changes were seen in the pre-existing skin lesions on the penis, scrotum and legs. In addition to a typical cornoid lamella, histological examination revealed a band-like infiltration beneath the epidermis, liquefaction degeneration of the basal cell layer and subsequent coagulative necrosis of the keratinocytes. We review similar ulcerative types of porokeratosis in the literature and discuss the significance of our unusual case.

Treatment of lichen amyloidosis (LA) and disseminated superficial porokeratosis (DSP) with frequency-doubled Q-switched Nd:YAG laser

BACKGROUND

Under normal practice, the full thickness of the epidermis is peeled off when treating pigmented lesions with a frequency-doubled Nd:YAG laser. Based on this observation, it is postulated that this laser may be effective for treating lichen amyloidosis (LA) and disseminated superficial porokeratosis (DSP) for which the pathologic changes are limited to the epidermis and papillary dermis.

OBJECTIVE

To investigate the clinical effect of frequency-doubled Nd:YAG laser treatment for one patient with LA and for one patient with DSP.

METHODS

Frequency-doubled 532 nm Nd:YAG laser pulses were delivered to the lesions on the limbs of a patient with LA and the face and forearms of a patient with DSP. Lesions of LA were treated two or three times, and those of DSP were treated four times, treatment sessions being 1 month apart. For this investigation, biopsies were taken from untreated lesions prior to treatment, lesions immediately after laser treatment, and lesions present at a 9-month follow-up investigation.

RESULTS

Both the patient with LA and the patient with DSP responded well to treatment, the results of which remained unchanged at a follow-up conducted 9 months after the final treatment session.

CONCLUSION

Frequency-doubled Nd:YAG laser treatment provided excellent results for the patient with LA as for the patient with DSP. The effectiveness of this method deserves further study in a larger group of test patients.

Guess what! Porokeratosis of Mibelli

A 72-year-old man had noticed, in his early forties, the appearance of well-defined papulous hyperkeratotic lesions, with increasing growth, located on both sides of his feet. After twenty-five years he consulted a dermatologist for the first time. Physical examination showed annular papules and rose-coloured plaques with atrophic centres, some of them hypopigmented, with higher and irregular borders, separated from the surrounding skin by longitudinal and well-defined furrows. The lesions presented variable sizes and shapes, some of them punctate, involving exclusively and in a bilateral form, both sides, back and sole of the feet (Figs. 1 and 2). The patient did not report any subjective symptoms. He was immunocompetent and did not remember that any relative had the same disease, nor had he been subjected to radiation treatment.

Porokeratotic eccrine ostial and dermal duct nevus: a case report and review of the literature

Hamartomas with eccrine differentiation are quite rare. There are 5 accepted classifications: eccrine nevus, eccrine-centered nevus, eccrine angiomatous hamartoma, eccrine syringofibroadenoma, and porokeratotic eccrine ostial and dermal duct nevus. The latter, PEODDN, typically presents as congenital keratotic papules and plaques located on the distal extremities. We report a classic case of PEODDN that was localized to the left hand since early childhood. The literature on this rare benign tumor is also reviewed.

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.

Porokeratosis in the elderly: a new subtype of disseminated superficial actinic porokeratosis

In a review of all cases of porokeratosis histologically diagnosed in our Department during the period 1991-98 we found that 12 patients (22%) were in their seventh to ninth decade. In all 12 (2 males and 10 females) the age of onset of the disease varied between 58 and 89 years (mean age 68.6 years). The clinical picture was similar in all the patients, with the number of lesions varying from a few to 20-50 annular plaques 10-15 mm in diameter, localized mainly on the lower limbs. We suggest that our patients had a very mild form of disseminated superficial actinic porokeratosis confined to the extremities with an unusually late onset. This peculiar variety of late-onset disseminated superficial actinic porokeratosis may represent a type of immunosuppression-induced porokeratosis where the pathologic clone for porokeratosis is present but remains latent until the amount of sun exposure, together with the physiological age-related lowering of immunocompetence, bring about its proliferation.

Bullous and pruritic variant of disseminated superficial actinic porokeratosis: successful treatment with grenz rays

We describe a case of intensively pruritic and partially bullous disseminated superficial actinic prorokeratosis, with acute flare-ups. Histopathological examination showed the characteristic cornoid lamella and subepidermal blister formation in one biopsy. Grenz ray treatment resulted in a marked regression of the skin lesions and pruritus.

Systematized porokeratotic eccrine and hair follicle naevus: report of a case and review of the literature

We report a unique case of a congenital keratinocytic naevus associated with severe alopecia, onychodysplasia and palmoplantar involvement in a 13-year-old girl. The lesions, consisting of scaly, spinous and verrucous papules and plaques, mainly followed Blaschko's lines and have remained unchanged since birth. The predominant histopathological picture was that of a column of parakeratosis overlying the eccrine ostia and hair follicles. This is the first case of a systematized keratinocytic naevus characterized by histopathology of eccrine and hair follicle porokeratosis and a widespread bilateral involvement. This may be a distinct entity to be included in the differential diagnosis of linear, hyperkeratotic dermatoses. We suggest its classification as systematized porokeratotic eccrine and hair follicle naevus.

Sudden onset of disseminated porokeratosis of Mibelli in a renal transplant patient

Porokeratosis is a disorder of epidermal keratinization of uncertain cause. Five clinical variants of porokeratosis have been described. These include porokeratosis of Mibelli, punctate porokeratosis, linear porokeratosis, porokeratosis palmaris plantaris et disseminata, and disseminated superficial porokeratosis. Disseminated superficial porokeratosis and single plaque porokeratosis of Mibelli have each been documented to occur in association with immunosuppression. To our knowledge, only 5 cases of disseminated porokeratosis of Mibelli in transplant recipients have been reported. We present a patient who developed explosive onset of disseminated porokeratosis of Mibelli shortly after renal transplantation. It is important to differentiate this unusual variety of porokeratosis from other cutaneous manifestations in transplant patients so that appropriate therapy can be instituted.

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.

p53, mdm-2, and p21 waf-1 in the porokeratoses

The etiology of the porokeratoses is unknown. Overexpression of the p53 tumor suppressor protein and disregulated cell cycle control have been pathogenically implicated. The p53 tumor suppressor gene product is regulated by mdm2 and both gene products influence cell cycle progression through the cyclin-dependent kinase inhibitor p21. Thirty-three cases of the various types of porokeratosis were immunohistochemically studied for p53, mdm2, and p21 proteins. Each of the cases showed increased p53 and decreased mdm2 and p21 expression within keratinocytes underlying cornoid lamella. This study confirms the previous findings of increased p53 staining and expands the potential roles of mdm2 and p21 in the pathogenesis of the porokeratoses.

Vulvar porokeratosis: case report and review of the literature

We report the first case of vulvar porokeratosis that occurred in a 39-year-old woman with a 30-year history of vulvar pruritus and disfiguring vulvar lesions. Ultrasonic surgical aspiration resulted in resolution of her pruritus and excellent cosmesis. Light microscopy revealed characteristic cornoid lamellae and electron microscopy confirmed the diagnosis of vulvar porokeratosis.

Disseminated superficial actinic porokeratosis like drug eruption: a case report

We report a 54-year-old male patient who developed an unusual form of generalized drug eruption. He had pain and breathlessness on the left chest wall. He had history of taking several drugs at private clinics under a diagnosis of herpes zoster. Two weeks later he had a generalized skin eruption. Examination showed multiple variable sized, mild pruritic, erythematous macules and papules on the face and upper extremities. Skin lesions take the form of a clinically consistent with disseminated superficial actinic porokeratosis (DSAP). Methylprednisolone 16 mg, astemisole 10 mg, oxatomide 60 mg was prescribed. Topical corticosteroid cream was applied. Within two months, his eruption had cleared almost completely. The pathogenetic mechanisms of this case are unclear, but drug and UV light have been considered.

The hyperkeratotic variant of disseminated superficial actinic porokeratosis (DSAP)

A 78-year-old South Korean man was referred to us from the Medical Intensive Care Unit (MICU) for an opinion. He was comatose and was on ventilatory care due to aspiration pneumonia. Multiple tiny papules had developed 10 years previously and since then the number and size had been increasing gradually. He had been diabetic for the past 4 years, and had Parkinson's disease diagnosed 1 year previously. Laboratory examinations revealed an elevated level of white blood cells (WBCs) (25,000/microL) and decreased hemoglobin (8.8 g/dL). Other laboratory results were negative or within normal limits. Skin examination showed multiple, discrete, crust-like, brownish papules over the erythematous base on the face, upper extremities, and lower extremities. With the clinical impressions of irritated verruca vulgaris, seborrheic keratosis, or cutaneous fungal infection, a skin biopsy was taken from a papule on the left shin, and histopathologic examination revealed several pronounced hyperkeratotic and parakeratotic columns, and characteristic cornoid lamellae in the stratum corneum. Beneath the cornoid lamellae, the granular layer was decreased. A number of round or oval, dyskeratotic, homogenized eosinophilic cells with pyknotic nuclei were scattered in the prickle cell layer below the cornoid lamellae. A mild lymphohistiocytic infiltrate was observed in the papillary dermis and around the blood vessels in the upper dermis. Also, actinic degeneration was present in the upper dermis.

Disseminated superficial porokeratosis with dermal amyloid deposits: case report and immunohistochemical study of amyloid

The association of porokeratosis with dermal amyloid deposits is extremely rare, only three cases are reported in the literature. We describe a case of disseminated superficial porokeratosis (DSP) with clear histologic evidence of amyloid deposition in the upper dermis. The amyloid was typed with an original immunohistochemical assay based on three anticytokeratin antibodies (MNF 116, CK1, KER B). The epidermal origin of the substance (K amyloid) was demonstrated by its strong positivity for MNF 116 and KER B.

Genitoanocrural porokeratosis following chronic exposure to benzene

Porokeratoses are disorders of epidermal keratinization, the aetiology of which remains to be elucidated. We present the uncommon case of a 70-year-old man with genitoanocrural porokeratotic lesions successfully treated by CO2 laser vaporization. The patient's occupational history and the late onset, site and multiplicity of the lesions suggest their induction by benzene, a known carcinogen.

Disseminated superficial actinic porokeratosis occurring in two members of an Asian family

Disseminated superficial actinic porokeratosis (DSAP) is a genodermatosis which usually affects fair-skinned individuals at sites of chronic sun exposure, although the face is usually spared. We now report the occurrence of this condition in a Pakistani mother and her 13-year-old daughter, both predominantly with facial lesions.

Disseminated superficial porokeratosis in a patient with chronic liver disease

A 55-year-old male suffering from liver cirrhosis presented with diffuse annular hyperkeratotic papules of abrupt onset on the trunk and extremities. Histopathologic examination revealed cornoid lamella and eosinophilic spongiosis. He did not receive any medications other than cephalosporin for spontaneous bacterial peritonitis. A review of the literature revealed that three cases developed porokeratosis when their liver function declined and that, in one case, the porokeratosis disappeared spontaneously with liver transplantation. Although the precise mechanism is unclear, there is evidence demonstrating immunoincompetence in cirrhosis. Even though we did not perform immunologic studies or exclude the possibility of drug-induced porokeratosis in our case, it is conceivable that porokeratosis can be triggered by immunosuppression due to liver cirrhosis per se.

Porokeratosis of Mibelli. Overview and review of the literature

Porokeratosis of Mibelli is an uncommon dermatosis, which may be associated with immunosuppression and may undergo malignant transformation. Due to the wide range of clinical presentations, numerous classifications have evolved, resulting in some confusion. This article examines the classification and presentation of porokeratosis and, in particular, reviews the association with immunosuppression.

p53 gene mutation analysis in porokeratosis and porokeratosis-associated squamous cell carcinoma

In this and previous studies, we have shown p53 overexpression immunohistochemically in 14 of 17 porokeratotic specimens obtained from 14 lesions of nine cases, and in all six specimens of squamous cell carcinoma (SCC) arising on porokeratotic lesions of two cases. We screened mutations in exons 5 to 10 of the p53 gene in all these specimens by polymerase chain reaction-single strand conformation polymorphism analysis. Mutations of the p53 gene were detected in two of the six SCCs but not in any of the 17 porokeratotic specimens. These two mutations were C to T transitions at codons 146 and 175 in exon 5, which were a nonsense mutation at a dipyrimidine site and a missense mutation at a CG site, respectively. To our knowledge, neither of these mutations has been identified in skin cancers before. Our observations indicate that mutations of the p53 gene are not the major molecular etiology for porokeratosis, but are related to its skin carcinogenesis, and that p53 overexpression in porokeratosis is not due to p53 gene mutations.

A case of disseminated superficial actinic porokeratosis subsequent to renal transplantation

Disseminated superficial actinic porokeratosis is characterized by the development of numerous annular keratotic lesions on sun-exposed areas, accompanied by pathological evidence of cornoid lamellae. We examined a case of disseminated superficial actinic porokeratosis in a 40-year-old male who had undergone renal transplantation and was being treated with immunosuppressants. Five years after surgery, he began to develop numerous eruptions. Some of these eruptions enlarged and developed over a second period of five years until he finally required hospitalization.

High incidence of porokeratosis in renal transplant recipients

Immunosuppression is a well-documented precipitant of porokeratosis (PK). However, PK is not considered among the most common cutaneous disorders in immunosuppressed patients. We studied prospectively a series of 103 renal transplant patients and found 11 cases (10.68%) of PK. Our series represents the highest incidence of PK in transplant patients reported so far. Our findings suggest that PK in transplant recipients may be more frequent than previously thought.

Cancer proneness of linear porokeratosis may be explained by allelic loss

BACKGROUND

It is well known that porokeratosis, a genetically heterogeneous disorder characterized by the histopathological feature of the cornoid lamella, shows an increased proneness to develop carcinoma. On the other hand, a significant mechanism in the origin of many forms of cancer is loss of heterozygosity or allelic loss.

OBJECTIVE

Because it has recently been proposed that linear porokeratosis may result from allelic loss, one might expect that linear porokeratosis is especially prone to malignant degeneration. In order to test this hypothesis, a review of case reports was performed.

METHOD

Cases of cancer-associated porokeratosis were collected from the European language literature and assigned to one of 5 different types [plaque type of Mibelli (PM); disseminated actinic superficial porokeratosis (DSAP); porokeratosis palmaris, plantaris et disseminata (PPPD); porokeratosis punctata palmaris et plantaris (PPPP); linear porokeratosis (LP)].

RESULTS

Malignant or premalignant lesions were reported in 9 cases of PM, 15 cases of DSAP, 3 cases of PPPD, 1 case of PPPP and 21 cases of LP.

CONCLUSION

This analysis supports the view that among the various forms of porokeratosis, the linear type is particularly susceptible to malignant degeneration. Arguments are presented in favor of the assumption that the genetic mechanism of allelic loss giving rise to LP may represent an initial step in the development of cancer.

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 keratoderma discreta, and suggest that porokeratotic palmoplantar keratoderma discreta is a variant of porokeratosis plantaris discreta.

A report of 31 cases of porokeratosis at the National Skin Centre

Porokeratosis is a well-recognised disorder of keratinization with distinctive clinical features and histological hallmark of cornoid lamella. There are at least 4 different clinical variants, with malignant transformation reported in almost all types of porokeratosis. This is a retrospective study on all cases of porokeratosis seen at the National Skin Centre, Singapore from 1990 to 1993. There was a total of 31 patients diagnosed to have porokeratosis during the study period. They can be classified into 4 main clinical variants: (1) disseminated superficial actinic porokeratosis (41.9%), (2) classical porokeratosis of Mibelli (35.5%), (3) porokeratosis palmaris, plantaris et disseminatum (9.7%), and (4) linear porokeratosis (12.9%). Our typical patient is in his/her early forties, who noticed asymptomatic porokeratotis lesion on sun-exposed skin. Various treatment modalities were used, with no one method being more superior to another. None of our patients had malignant transformation of pre-existing skin lesions during the short follow-up period from less than one year to three years. Patients should be advised to avoid excessive sunlight, to use sunscreen and go for periodic examination by a dermatologist with a view to close skin malignancy surveillance.

Disseminated superficial porokeratosis developing after electron-beam total skin irradiation for mycosis fungoides

A 74-year-old man with stage IB cutaneous T-cell lymphoma was treated with electron-beam total skin irradiation in 1988. Seven years later, multiple disseminated lesions of porokeratosis developed on the chest, extremities and abdomen. There was no family history of porokeratosis, nor history of treatment with PUVA or of excessive sun exposure. Development of disseminated porokeratosis on nonexposed sites suggests a direct role for the previous ionizing radiation. Electron-beam total skin irradiation therapy should therefore be added to the list of possible causative factors in the development of disseminated porokeratosis.

Porokeratosis of Mibelli and HIV-infection

BACKGROUND

The exacerbation of porokeratosis of Mibelli associated with inmunosuppression has been well documented.

MATERIALS AND METHODS

We describe the clinical and histologic data of three cases of HIV-infected patients, who developed porokeratosis following HIV-contact.

RESULTS

The three reported patients were found to have the clinical and histologic features of porokeratosis of Mibelli. Either the exacerbation or development of the disease followed HIV infection.

CONCLUSION

Although porokeratosis is not a disease indicative of AIDS, its flare-up or its presence in HIV-infected patients may serve as a marker of inmunodeficiency.

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.

Porokeratosis and cutaneous malignancy. A review

BACKGROUND

Porokeratosis is a disorder of epidermal keratinization manifested clinically by a raised border and histologically by a cornoid lamella. While cutaneous malignancy has been reported to arise in porokeratosis, the risk remains unknown. In the past it has been associated with a history of radiation therapy.

OBJECTIVE

The purpose of this study is to estimate the frequency of cutaneous malignancy arising in porokeratosis and define those patients who are at highest risk.

METHODS

All cases in the English language literature in the last 30 years were reviewed.

RESULTS

Twenty-one (7.5%) of 281 cases reported revealed a malignancy arising within porokeratosis. Large lesions, those of long-standing duration, and the linear type were at greatest risk. Radiation therapy was an infrequently identified risk factor.

CONCLUSION

Porokeratosis is a premalignant condition, with certain groups of patients at greatest risk for malignant transformation.