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Clinical and pathological study of lichen-planus-like keratosis in China.

Lichen-planus-like keratosis is usually diagnosed pathologically; rarely, a definitive diagnosis can be made grossly in the clinic. Only a few cases of lichen-planus-like keratosis have been reported in China. The purpose of this study was to investigate the clinical and pathological features of lichen-planus-like keratosis in China. Fifty cases of lichen-planus-like keratosis patients diagnosed pathologically during a 5-year period in our clinic were analyzed. Clinical features were recorded. Sectioned specimens were subjected to hematoxylin and eosin staining to observe pathological changes. Results showed that there were 34 males and 16 females (ratio 2:1) with an average age of 61.2 years. Most of the lesions were single papules or plaques with rough surfaces. They were distributed on the face, larger than 1 cm, and dark red to brown in color. Only one case (2%) was considered to be lichen-planus-like keratosis clinically. By hematoxylin and eosin staining, solar lentigo and solar elastosis could be found in 68% and 32% of lichen-planus-like keratosis lesions, respectively. Eosinophil (42%) and plasma cell (36%) infiltration was also found frequently. Exoerythrocytes could be detected in 50% of the cases. Lichen-planus-like keratosis is not uncommon in clinical practice in China, the diagnosis of lichen-planus-like keratosis should be made by a combination of clinical manifestations and pathological changes. It is better to classify lichen-planus-like keratosis as a benign skin tumor. More attention should be paid to lichen-planus-like keratosis in China.

Aged↗

The relationship between basal cell epithelioma and seborrheic keratosis. A study of 60 cases.

BACKGROUND: Various skin tumors can be seen rarely in association with seborrheic keratosis. We present 60 cases of seborrheic keratosis related to a basal cell epithelioma in the same specimen. OBJECTIVE: To report association of basal cell epithelioma with seborrheic keratosis and discuss the possibility of malignant change in seborrheic keratosis. METHODS: Sixty cases of seborrheic keratosis associated with basal cell epithelioma were studied. Tissues were fixed in neutral buffered formalin, processed, and stained with standard hematoxylin and eosin techniques. RESULTS: Histological evaluation showed a seborrheic keratosis associated with basal cell epithelioma in all of the cases. Basal cell epithelioma was attached with seborrheic keratosis in a majority of the cases (40/60) and appeared to represent a part of the same tumor. Both tumors were lying adjacent to each other in the rest of the cases (20/60). CONCLUSION: Malignant change in seborrheic keratosis is controversial. We recommend the histological evaluation of seborrheic keratosis especially when inflamed or atypical in appearance. This should not be taken as a mandate for pathological evaluation or for treatment of every seborrheic keratosis as though it was potentially malignant.

Adult↗

[Actinic keratosis and development of cutaneous squamous cell carcinoma].

BACKGROUND: Actinic keratosis is a common sun-induced skin disease. For many years there has been a great deal of discussion of the term used for the disease and of its classification. Recent molecular studies indicate an association between actinic keratosis and squamous cell carcinoma. MATERIAL AND METHODS: Review of recent reports on histological, molecular, biochemical and clinical findings in actinic keratosis and cutaneous squamous cell carcinoma. RESULTS AND INTERPRETATION: The morphology of atypical cells in both actinic keratosis and squamous cell carcinoma is identical. The risk of progression to squamous cell carcinoma is minimal, but up to 60% of squamous cell carcinoma cases begin as actinic keratosis. Regression of actinic keratosis occurs when sun exposure is decreased. Examination of possible chromosome aberrations and gene mutations in both actinic keratosis and squamous cell carcinoma reveals similar patterns, including the same mutation in the tumour suppressor gene TP53. Recent studies indicate that actinic keratosis is the earliest manifestation of a potentially malignant disease similar to carcinoma in situ in cervix uteri. Thus, actinic keratosis requires careful diagnosis and follow up.

Carcinoma in Situ↗

Prevalence of melanoma clinically resembling seborrheic keratosis: analysis of 9204 cases.

OBJECTIVE: To estimate the prevalence of melanoma clinically mimicking seborrheic keratosis. DESIGN: Retrospective review of cases submitted for histological examination with a clinical diagnosis of seborrheic keratosis or with a differential diagnosis that included seborrheic keratosis. SETTING: A tertiary medical care center-based dermatopathology laboratory serving academic dermatology clinics that have a busy pigmented lesion clinic. MATERIALS AND METHODS: A total of 9204 consecutive pathology reports containing a diagnosis of seborrheic keratosis in the clinical information field were identified between the years 1992 and 2001 through a computer database search. Reports with a final histological diagnosis of melanoma were selected for further review and clinicopathological analysis. MAIN OUTCOME MEASURE: Histological diagnosis, which was correlated with the preoperative clinical diagnosis. RESULTS: Melanoma was identified in 61 cases (0.66%) submitted for histological examination with a clinical diagnosis that included seborrheic keratosis. Melanoma was in the clinical differential diagnosis of 31 cases (51%). The remaining lesions had a differential diagnosis of seborrheic keratosis vs melanocytic nevus (17 cases, 28%), basal cell carcinoma (7 cases, 12%), or a squamous proliferation (3 cases, 5%). In 3 cases (5%), seborrheic keratosis was the only clinical diagnosis. All histological types of melanoma were represented. CONCLUSIONS: Our results confirm that melanoma can mimic seborrheic keratosis. These data strongly support the current policy of submitting for histological examination all specimens that have been removed from patients.

Adult↗

Keratosis pilaris rubra: a common but underrecognized condition.

BACKGROUND: Keratosis pilaris is a common skin disorder of childhood that often improves with age. Less common variants of keratosis pilaris include keratosis pilaris atrophicans and atrophodermia vermiculata. OBSERVATIONS: In this case series from dermatology practices in the United States, Canada, Israel, and Australia, the clinical characteristics of 27 patients with keratosis pilaris rubra are described. Marked erythema with follicular prominence was noted in all patients, most commonly affecting the lateral aspects of the cheeks and the proximal arms and legs, with both more marked erythema and widespread extent of disease than in keratosis pilaris. The mean age at onset was 5 years (range, birth to 12 years). Sixty-three percent of patients were male. No patients had atrophy or scarring from their lesions. Various treatments were used, with minimal or no improvement in most cases. CONCLUSIONS: Keratosis pilaris rubra is a variant of keratosis pilaris, with more prominent erythema and with more widespread areas of skin involvement in some cases, but without the atrophy or hyperpigmentation noted in certain keratosis pilaris variants. It seems to be a relatively common but uncommonly reported condition.

Adolescent↗

Evaluation of the effectiveness of imiquimod and 5-fluorouracil for the treatment of actinic keratosis: Critical review and meta-analysis of efficacy studies.

BACKGROUND: Actinic keratosis lesions occur frequently on sun-exposed skin of Caucasians. They become more prevalent with advancing age and are important in identifying the risk factor of those people possibly predisposed to invasive squamous cell carcinoma. Topical therapies are useful alternatives to cryotherapy for treating diffuse actinic damage and a number of preparations have been developed for treating actinic keratosis. OBJECTIVES: A cumulative meta-analysis was performed to determine the efficacy of imiquimod 5% cream, which presents a new alternative topical therapy for actinic keratosis, and to compare it to 5-fluorouracil for the treatment of actinic keratosis lesions of the face and scalp. METHODS: We searched MEDLINE (1966 to October 2004) for relevant studies evaluating the efficacy of actinic keratosis topical agents imiquimod and 5-fluorouracil (0.5%, 1%, and 5%). Studies included in this meta-analysis required a dosage regimen that was not significantly different from that approved by Health Canada and the U.S. FDA. Studies also required a well-defined treatment duration and followup period, with the primary efficacy variable being the complete (100%) clearance of all actinic keratosis lesions defined as the proportion of patients at followup with no clinically visible lesions in the treatment area. To determine the average efficacy rate for both drugs, the data from each study were combined for that drug. RESULTS: Ten studies were included in the analysis. The average efficacy rate for each drug (with 95% confidence interval) was 5-fluorouracil, 52 +/- 18% (n = 6 studies, 145 subjects) and imiquimod, 70 +/- 12% (n = 4 studies, 393 subjects). CONCLUSIONS: The results of this meta-analysis show that both imiquimod and 5-fluorouracil are effective methods for the treatment of actinic keratosis and provide a useful alternative to cryotherapy. However, this analysis suggests that imiquimod may have higher efficacy than 5-fluorouracil for actinic keratosis lesions located on the face and scalp and therefore provides another option to dermatologists.

Adjuvants, Immunologic↗

Pagetoid variant of actinic keratosis with or without squamous cell carcinoma of sun-exposed skin: a lesion simulating extramammary Paget's disease.

BACKGROUND: Extramammary Paget's disease usually occurs in anogenital skin. We present five cases of squamous cell carcinoma in situ of sun-exposed skin and non-squamous cell carcinoma in situ actinic keratosis that displayed atypical keratinocytes disposed in intraepithelial cell nests and immunohistochemical staining simulating extramammary Paget's disease. METHODS AND RESULTS: Two pilot cases--one squamous cell carcinoma in situ and one non-squamous cell carcinoma in situ actinic keratosis with formation of intra-epidermal nests of atypical keratinocytes with a pagetoid spread pattern--were encountered at our institution. Fifty-four consecutive cases of squamous cell carcinoma in situ including bowenoid actinic keratosis and 34 cases of non-squamous cell carcinoma in situ actinic keratosis were reviewed to identify pagetoid spread of atypical cells. Representative sections of all cases with pagetoid spread of atypical keratinocytes were submitted for special stains for mucin, and immunostaining for cytokeratin 7 (CK7), cytokeratin 20 (CK20), cytokeratin CAM 5.2 (CAM 5.2), carcinoembryonic antigen (CEA), vimentin and S100 protein. In the group of squamous cell carcinoma in situ, 10 cases displayed pagetoid spread of atypical keratinocytes with cytoplasm ranging from clear to pale and atypical hyperchromatic nuclei. One review squamous cell carcinoma in situ was multicentric with three separate lesions. The atypical keratinocytes tended to form well to poorly defined cell groups extending from the basal cell layer to the corneal layer. No similar cases were identified in the group of non-squamous cell carcinoma in situ actinic keratosis. Two pilot cases and three of 10 review cases with a total of seven separate lesions displayed a moderate to marked immunohistochemical reactivity for CK7 similar to extramammary Paget's disease. CEA immunoreactivity was also detected in two of these cases. In addition, two of 44 squamous cell carcinomas in situ without pagetoid spread of atypical keratinocytes showed a moderate reactivity for CK7 in very occasional atypical keratinocytes. The remaining seven squamous cell carcinomas in situ with pagetoid spread of atypical keratinocytes were not immunoreactive for CEA and CK7. Immunostaining for CK20, vimentin, S100 protein was negative in all atypical cells in all study cases. CONCLUSIONS: Actinic keratosis, particularly squamous cell carcinoma in situ of sun-exposed skin, may have histopathological and immunohistochemical features similar to extramammary Paget's disease and probably represents a variant of actinic keratosis. Awareness of the pagetoid variant of actinic keratosis arising in sun-exposed skin is helpful to avoid the over-diagnosis of extramammary Paget's disease.

Adult↗

Defective beta1-integrins expression in arsenical keratosis and arsenic-treated cultured human keratinocytes.

BACKGROUND: beta1-integrins, which localize to the basolateral surface of basal keratinocytes, are important in the differentiation control and proliferation of the epidermis. Many cutaneous diseases with perturbed differentiation, including arsenical keratosis, show altered patterns of integrin distribution and expression. Arsenic may induce arsenical keratosis through the differentiation and apoptosis aberration by integrins. The purpose of this study is to investigate the role of integrin and arsenic in the pathogenesis of arsenical keratosis. METHODS: Twenty-five specimens obtained from 25 patients with arsenical keratosis disease were studied. Immunohistochemistry staining to beta1, alpha2beta1, or alpha3beta1 integrins was performed in arsenical keratosis and clinically normal perilesional skin. Western blotting was used to assess the expression of integrin beta1 and focal adhesion kinase (FAK) in arsenic-treated cultured keratinocytes. RESULTS: A decreased expression of beta1, alpha2beta1, or alpha3beta1 integrins was demonstrated in arsenical keratosis and clinical normal perilesional skin in a large proportion of arsenical keratosis cases studied. The expressions of integrin beta1 and FAK were both decreased in arsenic-treated keratinocytes. CONCLUSIONS: Our results suggest that arsenic induces abnormal differentiation in arsenical keratosis via the effects of integrin expression in keratinocytes.

Aged↗

A possible case of eccrine poroma arising in seborrheic keratosis with partial intermediate malignancy and tumor of the follicular infundibulum.

An eighty-year-old woman presented with a eccrine poroma that appeared to have arisen in a seborrheic keratosis lesion on the right side of her abdomen. The tumor consisted of a brownish, flat, elevated lesion with an eroded nodule at its periphery. Histopathological analysis of the flat, elevated lesion revealed benign basaloid and squamoid cells that showed acanthotic upward proliferation, suggesting a seborrheic keratosis. The eroded nodule showed irregular proliferation of slight atypical squamoid cells with, in parts, ductal structures in the upper dermis, suggesting that it was an eccrine poroma with partial intermediate malignancy. In addition to the eroded nodule, an occult tumor clinically accompanied the seborrheic keratosis. Histopathology of the occult tumor revealed fenestrated columns and cords of pale epithelial cells attached to the base of the seborrheic keratosis lesion, which was diagnosed as a tumor of the follicular infundibulum. Although reports of seborrheic keratosis transforming into a sweat gland tumor are rare, the present case suggests that seborrheic keratosis may develop into benign or malignant adnexal tumors, including sweat gland and follicular tumors. Thus, seborrheic keratosis should be considered as a possible precursor of adnexal tumor.

Aged↗

Health economic evaluation of non-melanoma skin cancer and actinic keratosis.

Non-melanoma skin cancer (NMSC) and actinic keratosis are becoming an increasingly important healthcare problem. There are approximately 1 million cases of NMSC in the US each year, primarily basal cell carcinomas, and the incidence is increasing. Although NMSC is significant in terms of both health risk and the resource implications for treatment within healthcare systems, our understanding of the health economics of NMSC is limited. The purpose of this article was to systematically review and assess published health economic studies of the treatment of NMSC and actinic keratosis, taking into consideration key aspects of guidelines set by drug purchasers and key reimbursement agencies, and to provide recommendations for appropriate modelling approaches and data collection for health economic studies of NMSC and actinic keratosis. We systematically reviewed the published literature from 1965 to 2003 for health economic evaluations of treatments of NMSC and actinic keratosis using the search terms: ('skin cancer' or 'non melanoma skin cancer' or 'basal cell carcinoma' or 'actinic keratosis') and ('decision model' or 'decision theoretic' or 'decision analytic' or 'health economic' or 'cost effective'). Studies using one of the following methodologies were included: cost-effectiveness, cost-benefit, cost-utility, cost-minimisation, cost-of-illness, cost-consequence, and treatment cost analysis. We identified eight studies evaluating NMSC. One of these studies also evaluated actinic keratosis. Although several studies satisfied some of the basic requirements of health economic evaluations, the majority had serious shortcomings that limit their usefulness. There are a few high-quality health economic evaluations assessing treatments for NMSC or actinic keratosis. However, our analysis suggests that additional data on treatment practice patterns and epidemiology need to be collected, and incorporated with efficacy and safety data in a formal decision-analytic framework to assist decision makers in allocating scarce healthcare resources.

Clinical Trials as Topic↗

Comparative histochemical study of Bowen's disease and actinic keratosis: preserved normal basal cells in Bowen's disease.

The degree of DNA-instability as revealed by immunohistochemical staining with anti-cytidine antibody after acid hydrolysis (DNA-instability test) has been recently used as a marker of malignancy. This technique was applied to examine 17 skin tissue samples of Bowen's disease, 47 of actinic keratosis, 15 of squamous cell carcinoma, 5 of seborrheic keratosis, and 10 of normal skin. All benign neoplastic cells of seborrheic keratosis and normal epidermal cells were negative. On the other hand, all cancer cells were positive with the DNA-instability test, indicating their malignancy, but all basal cells in Bowen's disease were completely negative. Compatible with this result, the basal cells in Bowen's disease were characteristically normal as evident in other histochemical examinations. Thus, they were negative with p53 immunohistochemistry, with normal signals of chromosome 17 in situ hybridisation and argyrophilic nucleolar organiser region, and showed slightly enhanced proliferative activity as revealed by proliferating cell nuclear antigen immunohistochemistry. Immunohistochemical staining with 34 beta E12 (monoclonal antibody against cytokeratins 1, 5, 10, and 14), which stains all normal epidermal keratinocytes including basal cells, showed that only the basal cells of Bowen's disease stained strongly and homogeneously, while all cancer cells in the upper layers of Bowen's disease and all layers of actinic keratosis were only sporadically or weakly stained. Staining with 34 beta B4 (monoclonal antibody against cytokeratin 1), which recognises the whole epidermis except for the basal layer in the normal epidermis, showed that the basal cells in the Bowen's disease were completely negative, and lower layer cells in the actinic keratosis and upper layer cells in Bowen's disease were only sporadically stained positive, although the superficial layer cells in actinic keratosis stained strongly and homogeneously. Our findings clearly indicate that the basal cells in Bowen's disease are normal. In support of this conclusion, the same cells showed normal morphology on electron microscopy with preserved basement membrane, although the latter was often damaged in actinic keratosis.

Actins↗

The characteristics of human papillomavirus expression and cell proliferation in actinic keratosis and Bowen's disease of the skin.

The aim of our study was to elucidate the characteristics of HPV expression and cell proliferation in actinic keratosis and Bowen's disease of the skin. We examined immunocompetent patients with premalignant lesions of the skin such as actinic keratosis and Bowen's disease. 10 patients were involved in each group. Clinical study included gross features of lesion, growth rate, colour, size. Paraffin sections from biopsy specimens were were stained by hematoxylin-eosin and von Gieson. Immunohistochemistry was performed using monoclonal antibodies against HPV, oncoprotein p53, anti-apoptotic protein Bcl-2, proliferation marker PCNA. Strongly, moderately and weakly positive cells were counted. Actinic keratosis and Bowen's disease failed to show the specific clinical features, therefore, they can not be diagnosed based on clinical signs only and morphological examination seems to be mandatory. The immunohistochemical study has showed that in both actinic keratosis and Bowen's disease HPV was positive in 60%, and 40% were HPV-negative suggesting the similar incidence of HPV infection in these premalignant lesions. Our results suggest that HPV(+)/p53(+) types of actinic keratosis and Bowen's disease are characterized by higher proliferation activity in comparison to HPV(-)/p53(+) types, and expression of Bcl-2 is associated with HPV-negativity, therefore, these premalignant lesions of the skin require immunohistochemical examination with evaluation of expressions of human papillomavirus, proliferation marker PCNA and anti-apoptotic protein Bcl-2. The differential diagnosis of actinic keratosis and Bowen's disease should be based on the following immunohistochemical criteria: incidences of positivity for p53, Bcl-2 and PCNA are similar, but expression intensity and anatomical localization are different: their expressions are higher in Bowen's disease, positive cells are found primarily in upper epidermis in actinic keratosis, while whole epithelium is involved in Bowen's disease.

Adult↗

[Keratosis lichenoides chronica and prolonged exposure to infrared radiation].

BACKGROUND: We report a case of keratosis lichenoides chronica and prolonged exposure to a source of heat (infrared radiation). CASE REPORT: A 35 year-old man was examined for a symmetric and reticulate dermatosis on the abdomen, the interior of arms and lower extremities. The lesions had progressed over several months. They were characterized by hyperpigmentation, erythematous, bullous and squamous papules. These lesions were associated with those of the scalp, evoking seborrheic dermatitis. The patient was exposed to a source of heat with an electric radiator on his bare chest everyday. The skin biopsy showed a lichenoid reaction. All these elements allowed to put the diagnosis of keratosis lichenoides chronica, probably actived by the infrared light. DISCUSSION: Keratosis lichenoides chronica is a rare acquired dermatosis of the young adult. Its physiopathology remains elusive. This dermatosis is characterized by keratosic violaceous lichenoid papules distributed symmetrically. The eruption is usually asymptomatic. The histological examination indicates a lichenoid reaction. The progression is chronic and the disease is very resistant to therapy. Keratosis lichenoides chronica has never been described as being able to be induced by Koebner's phenomenon. In the literature, two cases of erythema ab igne were associated with lichen planus. For some authors, keratosis lichenoides chronica is an entity itself, for others it would be related to lichen planus. These arguments enabled us to diagnose keratosis lichenoides chronica probably activated by the infrared light.

Adult↗

Lichenoid benign keratosis.

A histopathologic study of 108 lesions of lichenoid benign keratosis from 104 patients confirmed previously observed clinicopathologic features such as involvement of whites, age range of 35 to 65 years, female predominance, single keratosis, common location on the arm or presternal area, and failure of clinical recognition of the lesion. Histologically, lichenoid benign keratosis can be diagnosed by the characteristic lichenoid appearance, parakeratosis, an infiltrate occasionally containing plasma cells and eosinophils, and remnants of lentigo-like changes at the periphery of the lesion. The clinical information of a solitary lesion and suspicion of a premalignant or malignant diagnosis aids in establishing the pathologic diagnosis of the disease. Direct immunofluorescence studies of tissue from seven lesions of lichenoid benign keratosis resembled those seen in lichen planus. Features distinguishing lichenoid benign keratosis from lichenoid solar keratosis are discussed.

Adult↗

Two cases of basal cell carcinoma arising in seborrheic keratosis.

The present study reports two cases of basal cell carcinoma arising in seborrheic keratosis. The first case is a seventy-three-year-old female who presented with a blackish nodule arising from a pigmented lesion on her chest. Histopathological analysis of the nodule and the pigmented lesion revealed a basal cell carcinoma with hair follicular differentiation and an acanthotic seborrheic keratosis, respectively. The second case is a seventy-year-old female with a blackish nodule arising from a pigmented lesion on her back. Histological analysis of the nodule revealed an atypical basaloid cell mass surrounded by a seborrheic keratosis lesion. In addition to the coexisting seborrheic keratosis with the basal cell carcinoma, a basaloid follicular hamartoma that showed multiple hamartomatous hair follicles or small cysts replaced by a branching cord or lace-like network of basaloid cells surrounded by fibrovascular stroma was identified. We concluded that both cases presented a rare combination of a seborrheic keratosis which underwent a malignant change to basal cell carcinoma. It appears that both basal cell carcinomas and seborrheic keratosis may derive from a similar source: pluripotential cells of either the epidermis or hair follicle epithelium.

Aged↗

Alterations of p53 gene and Ha-ras gene are independent events in solar keratosis and squamous cell carcinoma.

In order to clarity the multiple-step progression from solar keratosis to squamous cell carcinoma, aberrations of the p53 gene (exons 2-11) and ras genes (exons 1 and 2) in solar keratosis and squamous cell carcinoma were investigated by polymerase chain reaction and single-strand conformation polymorphism analysis. In a series of Japanese patients, eight of 27 (30%) samples of solar keratosis and three of six (50%) samples of squamous cell carcinoma showed structural abnormalities in the p53 gene. Only one solar keratosis (4%) showed a point mutation in the Ha-ras gene but not in the p53 gene. Among these cases, no mutation of ras genes could be detected in squamous cell carcinoma. Simultaneous mutation of ras genes and the p53 gene was not detected in any cases of either solar keratosis or squamous cell carcinoma. It is concluded that aberrations of the p53 gene and ras genes are induced through independent processes of ultraviolet irradiation in the course of carcinogenic change from solar keratosis to squamous cell carcinoma.

Carcinoma, Squamous Cell↗

Dermoscopy of pigmented seborrheic keratosis: a morphological study.

OBJECTIVES: To describe morphological features of seborrheic keratosis as seen by dermoscopy and to investigate their prevalence. DESIGN: Prospective cohort study using macrophotography and dermoscopy for the documentation of seborrheic keratosis. SETTINGS: Seborrheic keratoses were prospectively collected in 2 sites: a private practice in Plantation, Fla (site 1), and the Department of Dermatology at the University Hospital Geneva in Switzerland (site 2). PATIENTS: A total of 203 pigmented seborrheic keratoses (from 192 patients) with complete documentation were collected (111 from site 1 and 93 from site 2). INTERVENTIONS: Screening for new morphological features of seborrheic keratosis and evaluation of all lesions for the prevalence of these criteria. MAIN OUTCOME MEASURES: Identification of new morphological criteria and evaluation of frequency. RESULTS: A total of 15 morphological dermoscopic criteria were identified. Standard criteria such as milialike cysts and comedolike openings were found in a high number of cases (135 and 144, respectively). We found network and networklike structures to be present in 94 lesions (46%). Using standard diagnostic criteria for seborrheic keratosis, 30 lesions would not have been diagnosed as such. CONCLUSIONS: The classic dermoscopic criteria for seborrheic keratosis (milialike cysts and comedolike openings) have a high prevalence but the use of additional dermoscopic criteria such as fissures, hairpin blood vessels, sharp demarcation, and moth-eaten borders improves the diagnostic accuracy. The proper identification of pigment network and networklike structures is important for the correct diagnosis.

Biopsy, Needle↗

Lymphomatoid keratosis: an epidermotropic type of cutaneous lymphoid hyperplasia: clinicopathological, immunohistochemical, and molecular biological study of 6 cases.

OBJECTIVE: To provide evidence that lymphomatoid keratosis should be categorized as an epidermotropic subtype of cutaneous lymphoid hyperplasia. DESIGN: Clinicopathological, immunohistochemical, and molecular biological studies of epidermotropic and dermal bandlike infiltrates of lymphocytes without necrotic keratinocytes, Civatte bodies, or Max-Joseph spaces and solar lentigo or seborrheic keratosis adjacent to the lesion, but with epidermal hyperplastic change (clinically scaly plaque) in cases of lymphomatoid keratosis. Conventional histopathologic study as well as immunohistochemical examinations for CD1a, CD3, CD4, CD8, CD20, and CD79a and S100 protein and genotypic examinations were performed. SETTING: University departments comprising 2 sections of dermatology and 1 section of pathology. MAIN OUTCOME MEASURES: Ratio of T to B cells and of CD4(+) to CD8(+) cells, and the phenotype of epidermotropic cells were evaluated. Gene rearrangement of the immunoglobulin heavy chain gene and T-cell receptor (TCR)-beta and TCRgamma genes was also investigated by the polymerase chain reaction method. RESULTS: Immunohistochemically, epidermotropic CD20(+) and/or CD79a(+) cells were present. In the upper dermal lymphocytic infiltrates, the CD3(+)/CD79a(+) cell ratio ranged from 5:5 to 8:2. The CD4(+)/CD8(+) cell ratio was within normal limits. Rearrangements of the TCRgamma gene were demonstrated in 2 cases and of the TCRbeta gene in 1 case. CONCLUSIONS: Our results indicate that lymphomatoid keratosis is a clinically benign keratotic lesion but histologically malignant, simulating mycosis fungoides. Immunohistochemical findings showed a reaction pattern in all cases, but genotypical examination showed some clonal dermatoses. Therefore, "lymphomatoid" keratosis should be classed as a pseudolymphoma, namely, a subtype of cutaneous lymphoid hyperplasia with epidermotropism.

Adult↗