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.     

Comedo-like openings in melanoma

We describe a case of melanoma with the presence of comedo-like openings at dermoscopy. These structures, typical of seborrheic keratosis, represent an uncommon finding in melanoma. We emphasize the importance of searching for specific dermoscopic criteria for melanocytic lesions during the examination of a pigmented lesion, despite possible observations of characteristic structures of non-melanocytic lesions, in order to increase the accuracy in the diagnosis of melanoma.     

Pigmented seborrheic keratoses of the vulva clinically mimicking a malignant melanoma: a clinical, dermoscopic-pathologic case study

The diagnosis of seborrheic keratosis is, in general, a clinical one, but in some cases, the differential diagnosis between pigmented seborrheic keratosis and malignant melanoma is difficult. Dermoscopy may improve the early diagnosis of vulvar melanoma and thus play a role in the preoperative classification of pigmented lesions at this particular site. We report the first case of a pigmented seborrheic keratosis of the vulva clinically mimicking a malignant melanoma, whose dermoscopic features have been investigated together with their pathologic correlates. Dermoscopically our case shows the absence of comedo-like openings and the presence of the pseudo-network. Dermoscopy is therefore a useful method for the differential diagnosis of pigmented lesions even in the vulva.     

Eccrine porocarcinoma arising in a seborrheic keratosis evaluated with dermoscopy and treated with Mohs' technique

A 78-year-old white woman returned for a routine 6-month skin cancer examination. She had a history of actinic keratosis and multiple basal cell carcinomas. She had no personal or family history of dysplastic nevi or melanoma. The patient was asymptomatic and unaware of any new or changing skin lesions. The patient had multiple lentigines, hemangiomas, and actinic and seborrheic keratoses on all sun-exposed areas. There were no less than 10 seborrheic keratoses on the right mid-back, and one was found to have a 1-cm, reddish nodule asymmetrically located within it (Figs 1 and 2). A clear papule on the left preauricular area was found on biopsy to be a basal cell carcinoma. The nodule on the back was still present 1 month later and it was felt that further evaluation was indicated. As melanoma has been reported to develop in seborrheic keratoses, we decided to examine the lesion using digital dermoscopy. With digital dermoscopy, a well-demarcated reddish nodule was asymmetrically located within a brown lesion. It blanched significantly with pressure. Within the nodule, there were dotted and irregular linear vessels (atypical vascular pattern; also known as polymorphous vascular pattern) and regular-appearing brown dots. Surrounding the reddish nodule, there were pale and pigmented, comedo-like openings, fissures, and ridges (brain-like appearance). Some of the follicular openings appeared to be within the wall of the nodule (Figs 3 and 4). Comedo-like openings, fissures, and ridges are primary dermoscopic criteria for the diagnosis of a seborrheic keratosis; however, the vascular pattern seen has not been reported in seborrheic keratosis. Due to the patient's age and the rarity of significant pathology arising in a seborrheic keratosis, a shave biopsy was performed. To our surprise, the specimen was interpreted by an experienced dermatopathologist as a well-differentiated eccrine porocarcinoma. Due to the high local recurrence rate and metastatic potential of this carcinoma, the patient was referred for Mohs' surgery. Both the basal cell carcinoma and the eccrine porocarcinoma were excised in one stage. A metastatic work-up was negative and the patient appears to be doing well.     

Key points in dermoscopic differentiation between lentigo maligna and solar lentigo

A clinical diagnosis of lentigo maligna at an early stage is often difficult even for experienced dermatologists. Differential diagnoses would include solar lentigo, early lesions of seborrheic keratosis, lichen planus-like keratosis, pigmented actinic keratosis and melanocytic nevus. Dermoscopy has been shown to have higher diagnostic accuracy, especially in the diagnosis of pigmented skin lesions, in the past two decades. To aim of the present study was to review the diagnostic key points on dermoscopy in the published work to differentiate lentigo maligna from other differential diagnoses and reassess these important features on dermoscopy for specificity by describing the findings in detail. Diagnostic key points for lentigo maligna/lentigo maligna melanoma on dermoscopy are asymmetrical pigmented follicular openings, rhomboidal structures, annular-granular structures and gray pseudo-network. Lentigo maligna, at first, seems to occur as asymmetrical pigmented follicular openings and/or annular-granular structures, then expand and develop into the rhomboidal structures. Annular-granular structures and gray pseudo-network seem to be observed also in regressive areas of solar lentigo/initial seborrheic keratosis, lichen planus-like keratosis and pigmented actinic keratosis. The four important criteria on dermoscopy for the diagnosis of lentigo maligna have been reviewed, and the former two criteria seem to be more specific, but it might be difficult to recognize these findings without misinterpretation. The latter two seem to be not so specific as they would also be demonstrated in other pigmented epidermal lesions, although the distribution of the structures in these disorders would be inclined to be more homogeneous than that of lentigo maligna.     

Seborrheic keratoses, solar lentigines, and lichenoid keratoses. Dermatoscopic features and correlation to histology and clinical signs

Evaluation of the three benign lesions discussed here form the basis for dermoscopic evaluation of other pigmented skin lesions. The features of seborrheic keratosis, including [figure: see text] the various forms of fissures, comedo-like openings, and milia-like cysts, often allow easy interpretation of seborrheic keratosis; however, similar structures are commonly associated with melanocytic neoplasms, notably congenital nevi. Understanding solar lentigo and its dermoscopy features allows for the appreciation of pigment networks common in lentiginous melanocytic nevi and melanoma. The lichenoid keratosis is the model for lichenoid inflammation elsewhere, notably in halo nevi, regressing melanoma, and other melanocytic neoplasms with significant host inflammatory reactions.     

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.     

Wachsende Pigmentl?sion der linken Wange

A 75-year-old man presented after recurrence of a pigmented macule on his left cheek. Approximately 8 month before a seborrheic keratosis had been diagnosed clinically and treated with cryosurgery and curettage. Dermatoscopy of the recurrent lesion revealed a number of criteria associated with lentigo maligna including asymmetric pigmented follicular openings, streaks, rhomboidal structures, and homogeneous slate-gray areas. Histopathology confirmed a lentigo maligna melanoma with a Breslow tumor thickness of 0.3 mm.     

Regressing seborrheic keratosis - clinically and dermoscopically mimicking a regressing melanoma

The diagnosis of seborrheic keratosis is a clinical diagnosis. In a certain percentage of cases, differential diagnosis between seborrheic keratosis and malignant melanoma is difficult. We describe a case of regressing seborrheic keratosis simulating malignant melanoma. Clinical, dermoscopic and histopathologic examinations were performed for the occurrence of an asymmetric, irregularly demarcated, irregularly pigmented lesion measuring 1.3 x 1.5 cm on the right part of the abdomen in a 76-year-old male Caucasian. In order not to miss melanoma, the excision and histopathologic examination of the lesion with peppering is essential.     

Optical transfer diagnosis of pigmented lesions: a pilot study

Objective: To evaluate the potential of a novel imaging technology, optical transfer diagnosis (OTD), for differentiation of benign from malignant pigmented melanocytic lesions.
Design: Patients with pigmented lesions suspicious for melanoma were referred for OTD. After scanning, lesions were biopsied for histopathologic examination, each by two separate dermatopathologists. To create morphologic–physiologic maps, the imaging system used the morphologic and physiologic parameters derived from prediction models of light absorption and scattering by chromophores such as hemoglobin, keratin, and melanin at different epidermal and dermal depths. The relative entropies were analyzed for output prediction of malignancy vs. nonmalignancy.
Setting: General dermatology clinic in a tertiary care academic medical center.
Patients: Fifty patients with suspected melanoma.
Intervention: OTD of pigmented lesions suspicious for melanoma, followed by biopsies for histopathologic examination.
Main outcome measures: Histopathologic confirmation of malignant lesions identified by OTD as melanoma.
Results: Sixty-three pigmented suspicious lesions were scanned before being biopsied for histopathologic examination by the two dermatopathologists. Of the 63 lesions, five were identified as melanoma and 58 were found to be benign (including three seborrheic keratoses and 55 melanocytic nevi). OTD was able to identify the malignant lesions with 100% sensitivity and 94.8–96.6% specificity.
Conclusions: Further study is indicated, but this technology is a promising adjunct to clinical skin cancer screening. Additionally, if the physiologic prediction models can be validated, OTD may facilitate the noninvasive study of some aspects of cutaneous physiology.     

Pigmented malignant hidroacanthoma simplex mimicking irritated seborrheic keratosis

Pigmented variant of malignant hidroacanthoma simplex (PMHS) is very rare. We are aware of only two reported cases, all arising in pigmented hidroacanthoma simplex (HS). We report the third case of PMHS arising in a pigmented HS. A 71-year-old-woman presented with a well-demarcated pigmented hyperkeratotic tumor on the right knee resembling irritated seborrheic keratosis. Histopathologic examination of the excised tumor revealed intraepidermal proliferation of atypical polygonal poroid cells forming large, sharply demarcated nests with colonization of dendritic melanocytes. In addition, there were focal changes of a benign pigmented HS and syringofibroadenoma. The key diagnostic features of ductal structures and intracytoplasmic lumina were highlighted by carcinoembryonic antigen and epithelial membrane antigen immunostaining. PMHS should be differentiated from irritated seborrheic keratosis, melanoacanthoma, Bowen's disease and malignant melanoma both clinically and pathologically.     

Biopsy guided by dermoscopy in cutaneous pigmented lesion - Case report

It may be clinically difficult to differentiate early-stage melanoma from benign tumors, specially pigmented seborrheic keratosis. Dermoscopy can help; however, the findings are not always conclusive. Therefore, histopathology may be necessary for a correct diagnosis. We describe a melanocytic lesion with dubious clinic and dermoscopic findings. An incisional biopsy of a suspicious area, guided by dermoscopy, was performed to clarify the findings.     

A comparison of dermoscopic features among lentigo senilis/initial seborrheic keratosis, seborrheic keratosis, lentigo maligna and lentigo maligna melanoma on the face

Clinical differentiation of facial lentigo senilis/initial seborrheic keratosis (LS/ISK), seborrheic keratosis (SK), lentigo maligna (LM), and lentigo maligna melanoma (LMM) can be difficult. Dermoscopy improves the diagnoses in pigmented skin lesions (PSLs), but it is not helpful for the sun-exposed face because of the flat rete ridges without network-derived features. Therefore, development of new diagnostic criteria for this particular localization is a current issue of dermatology. In this retrospective study, dermoscopic slides of facial pigmented skin lesions of 66 patients referred to two clinics in Turkey were evaluated. Our aim was to determine the reliability of dermoscopy in the differentiation of these entities. The facial PSLs of 66 patients (34 males and 32 females) (median age: 58.2) were photographed with a Dermaphot (Heine, Hersching, Germany) over a five year period from November of 1995 to May of 2000. All of the dermoscopic slides were analysed according to 27 dermoscopic criteria developed by Schiffner et al. This data set contained 22 histologically proven malignant (14 LM, 8 early LMM) and 44 benign (18 SK, 26 LS/ISK) PSLs. In general, asymmetric pigmented follicular openings, dark streaks, slate-gray streaks, dark globules, slate-gray globules, dark dots, dark rhomboidal structures, light brown rhomboidal structures, dark homogeneous areas and dark pseudonetworks were statistically significant for malignant growth. On the other hand, milia-like cysts, pseudofollicular openings, cerebriform structures, light brown globules, light brown dots, light brown homogeneous areas, yellow opaque homogeneous areas, and light brown pseudonetworks were statistically significant for benign growth. This research emphasizes that dermoscopic features on the face differ from criteria used in other locations of the body. Analysis of the data suggests that dermoscopy can be used in the differentiation of LS/ISK, SK, LM and LMM from each other.     

Melanoma and seborrheic keratosis differentiation using texture features

Purpose: To explore texture features in two-dimensional images to differentiate seborrheic keratosis from melanoma.
Methods: A systematic approach to consistent classification of skin tumors is described. Texture features, based on the second-order histogram, were used to identify the features or a combination of features that could consistently differentiate a malignant skin tumor (melanoma) from a benign one (seborrheic keratosis). Two hundred and seventy-one skin tumor images were separated into training and test sets for accuracy and consistency. Automatic induction was applied to generate classification rules. Data analysis and modeling tools were used to gain further insight into the feature space.
Result and Conclusions: In all, 85–90% of seborrheic keratosis images were correctly differentiated from the malignant skin tumors. The features correlation_average, correlation_range, texture_energy_average and texture_energy_range were found to be the most important features in differentiating seborrheic keratosis from melanoma. Over-all, the seborrheic keratosis images were better identified by the texture features than the melanoma images.     

Key points in dermoscopic diagnosis of basal cell carcinoma and seborrheic keratosis in Japanese

Basal cell carcinoma (BCC) and seborrheic keratosis (SK) are representative pigmented skin tumors, and they are differentiated as non-melanocytic lesions in the two-step dermoscopy algorithm proposed by the Consensus Net Meeting on Dermoscopy. Because most BCC in Japanese patients are pigmented clinically, dermoscopy plays an important role in their differential diagnosis. The dermoscopic criteria for BCC include the lack of a pigment network and the presence of at least one positive feature for BCC, such as large blue-gray ovoid nests, multiple blue-gray globules, leaf-like areas, spoke wheel areas, arborizing vessels and ulceration. Whereas various dermoscopic features are seen in SK, comedo-like openings, milia-like cysts, and fissures and ridges are especially important features. It is necessary for clinicians to consider the pathological conditions causing the dermoscopic features of BCC and SK. In addition, the sensitivity and specificity of each feature should be taken into consideration to ensure an accurate dermoscopic diagnosis.     

Simultaneous occurrence of junctional nevus and seborrheic keratosis

A 45-year-old man presented with a pigmented lesion on his face. A clinical diagnosis of melanocytic nevus was made and the lesion was excised. Histopathologic examination showed a reticular seborrheic keratosis associated with a junctional nevus. We discuss the relation of nevocellular nevi with epidermal and adnexal tumors.     

Differences in the Known Cellular Composition of Benign Pigmented Skin Lesions Reflected in Computer-Aided Image Analysis

Background

Computer-aided image analysis (CAIA) has been suggested as an effective diagnostic tool for pigmented skin lesions (PSLs), especially melanoma. However, few studies on benign PSLs have been reported.

Objective

The purpose of this study was to evaluate benign PSLs with our CAIA software and analyze the differences between the parameters of those lesions.

Methods

By using homegrown CAIA software, we analyzed 3 kinds of PSLs-nevus, lentigo, and seborrheic keratosis. The group of seborrheic keratosis was divided into pigmented seborrheic keratosis, sebolentigine, and hyperkeratotic seborrheic keratosis. The CAIA was used to extract the color, as well as the morphological, textural, and topological features from each image.

Results

In line with clinical observations, the objective parameters indicated that nevus was dark and round, lentigo was small and bright, and seborrheic keratosis was large and spiky. The surface of nevus showed the highest contrast and correlation. In topological analysis, the concentricity clearly separated melanocytic lesions from seborrheic keratosis. The parameters of pigmented seborrheic keratosis were between those of typical nevus and seborrheic keratosis.

Conclusion

We confirmed that definite correlations exist between the subjective differentiation by experts'' examination and the objective evaluation by using CAIA. We also found that the morphological differences observed in CAIA were greatly influenced by the composition ratios of keratinocytes and melanocytes, which are already known histopathological characteristics of each PSL.     

Dermoscopic evaluation of vascular structures of various skin tumors in Japanese patients

Dermoscopic analysis of skin tumor has been mainly focused on pigmented structures. Recently, several different morphological types of vessels were found to be well associated with pigmented or non‐pigmented skin tumors in white subjects. Therefore, the recognition of such vascular structures has been applied for diagnostic purposes. As little statistical information on the various pigmented skin tumor vessels of Japanese patients has been reported, we therefore tried to evaluate the association between various vascular structures and 741 tumor lesions of Japanese patients. Vascular structures were dermoscopically recognized in 41 of 102 cases of melanoma, 104 of 119 basal cell carcinoma (BCC), 86 of 257 seborrheic keratosis (SK), 35 of 210 dermal and compound nevus (DN/CN), six of 12 squamous cell carcinoma (SCC) and 16 of 41 Bowen disease (BD). The structures of arborizing and glomerular vessels statistically revealed diagnostic specificity for BCC and BD, respectively, and hairpin vessels were helpful for differentiating SK from other pigmented tumors, as already reported in white patients. The most common vascular pattern observed in melanoma was the linear–irregular structure, but this pattern in Japanese patients had less diagnostic value than in white patients, because its sensitivity was not significantly higher than in SCC. The most remarkable differences between our study and previous reports with white patients were low frequency and sensitivity of dotted, comma and polymorphous vessels in lesions of melanoma, BCC and DN/CN; these vessels had less diagnostic value for Japanese patients. Finally, the frequency of vascular structures observed in melanoma rose along with the increase of the Breslow’s tumor thickness, and 88% of melanomas with vascular vessels revealed tumor thicknesses of more than 2 mm.     

Melanocytes express 3G5 surface antigen

The 3G5-reactive ganglioside antigen (3G5 antigen) is expressed on the surface of various cell types including pericytes, pancreatic islet cells, thyroid follicular cells, and cells of the pituitary and the adrenal medulla. Expression on melanocytes has not yet been reported. We examined 148 5-microm cryosections of 12 normal skin samples and 45 skin tumors (21 melanocytic nevi, 8 malignant melanoma primaries, 4 metastases of malignant melanoma, 3 basal cell carcinomas, and 9 pigmented seborrheic keratoses) by triple fluorescence technique with the monoclonal antibody 3G5, DNA fluorochrome, and the anti-melanocytic antibody A103 (Anti-Melan-A). In normal skin, 3G5 reactivity was detected in epidermal melanocytes of 4 of 12 cases with 14.8 +/- 24.1% positive melanocytes; 20 of 21 nevi (72.2 +/- 29.1% positive nevus cells, mean +/- SD), 8 of 8 primary melanomas (83.9 +/- 12.3% positive melanoma cells), and 4 of 4 melanoma metastases (82.5 +/- 6.5% positive melanoma cells) expressed the 3G5 antigen. All tumor cells of investigated basal cell carcinoma or seborrheic keratosis were 3G5 negative. This is the first report of 3G5 antigen expression in melanocytes. The data demonstrate high expression of this ganglioside in the aggregated melanocytes of malignant or benign tumors but low or absent expression in singular melanocytes (normal epidermis, seborrheic keratoses) reflecting a different biologic state.     

Differentiation of melanoma from benign mimics using the relative‐color method

Background: Previous studies have successfully classified 86% of malignant melanomas using a relative‐color segmentation method, by feature extraction from photographic images in the automatic identification of skin tumors. These studies were extended by applying the relative‐color method to dermoscopic images of melanoma grouped with melanoma in situ and clark nevus lesions in dermoscopic images allow more control over lighting variations, which contribute to lesion misclassification. Dermoscopic images then enable a more detailed examination of the structure of skin lesions, provide much more structural detail within lesions, and contain visual information that cannot be seen in photographic images. This present work extends the previous studies by applying relative‐color feature extraction to dermoscopic images to differentiate among melanoma, seborrheic keratoses and Reed/Spitz nevi. Objective: To develop a method for automatically differentiating among malignant melanoma, seborrheic keratoses and Reed/Spitz nevi, using digitized, color, dermoscopic images. Methods: Images underwent preprocessing, tumor segmentation, feature extraction and tumor classification. The relative‐color method was used in the segmentation stage. Classification was accomplished by taking the inner products of model tumor feature vectors with test‐image tumor vectors followed by the nearest‐neighbor classification method. Results: The classification rates of melanoma, seborrheic keratoses and Reed/Spitz nevi images mixed together, were 60%, 58.3% and 80%, respectively. Classification of melanoma and Reed/Spitz nevi mixed, were 70% and 90%, respectively. Classification rates were the best when melanoma was being differentiated from seborrheic keratoses. These rates were 100% and 88.9%, respectively. Conclusion: Dermoscopic rather than photographic images were preprocessed, using a hair‐removal technique. They were then converted to relative‐color images, which were segmented using the principal components transform and median split, followed by morphological filtering. After processing, the multi‐dimensional tumor feature space described herein was used to differentiate the tumors. The high success rates for differentiating seborrheic keratoses from melanoma show that the use of dermoscopic images has a strong promise in enabling prescreening, as well as automated assistance and significant improvement in tumor diagnosis in clinics.