Conventional and Polarized Dermoscopy Features of Dermatofibroma

Dermoscopy and reflectance confocal microscopy of solitary flat pink lesions: A new combined score to diagnose amelanotic melanoma

BACKGROUND

Differential diagnosis of amelanotic/hypomelanotic melanoma among solitary flat pink lesions is challenging, due to limited clinical and dermoscopic clues. Dermoscopy and reflectance confocal microscopy assessments improve diagnostic accuracy, but their combined capacity among solitary flat pink lesions is yet to be defined.

OBJECTIVES

To determine (i) whether diagnostic accuracy is improved with combined dermoscopy and reflectance confocal microscopy, (ii) a model to estimate probability of flat amelanotic/hypomelanotic melanoma among solitary flat pink lesions.

METHODS

A retrospective single-centre study of solitary flat pink lesions, excised for suspected malignancy between 2011 and 2022 was performed. Images were independently evaluated by two dermatologists, blinded to histopathological diagnosis. Diagnostic performance was evaluated on the receiver operating characteristic curve and the area under the curve. Predictive features were identified by univariate and multivariate logistic regression analyses. A final predictive nomogram of independent risk factors was calculated by backward likelihood ratio. Hypothesis being tested was formulated before data collection.

RESULTS

A total of 184 patients (87 females, 47.3%) were included; mean age was 57.6 years (19-95). Combined dermoscopy and reflectance confocal microscopy was more sensitive (83%, CI 69.2-92.4 and 91.5%, CI 79.6-97.6) than dermoscopy alone (76.6%, CI 62.0-87.7 and 85.1%, CI 71.7-93.8). Predictive features defined the new model, including linear irregular vessels (4.26-folds, CI 1.5-12.1), peripheral pigment network (6.07-folds, CI 1.83-20.15), remnants of pigmentation (4.3-folds, CI 1.27-14.55) at dermoscopy and atypical honeycomb (9.98-folds, CI 1.91-51.96), disarranged epidermal pattern (15.22-folds, CI 2.18-106.23), dendritic pagetoid cells in the epidermis (3.77-folds, CI 1.25-11.26), hypopigmented pagetoid cells (27.05-folds, CI 1.57-465.5), and dense and sparse nests (3.68-folds, CI 1.24-10.96) in reflectance confocal microscopy. Diagnostic accuracy of the model was high (AUC 0.91).

CONCLUSIONS

Adjunctive reflectance confocal microscopy increases diagnostic sensitivity of flat amelanotic/hypomelanotic melanoma differential diagnosis. The proposed model requires validation.

Dermoscopic evaluation of cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is an endemic disease in Iraq that is caused by protozoan infection. Dermoscopy has been applied to help in the diagnosis of multiple skin disease, including infestations. To evaluate the dermoscopic characteristics of CL lesions and their relationship with the disease duration, site, and pattern. Dermoscopic examination using (3 Gen Dermlite DL 100) at tenfold magnification of 91 lesions in 67 patients was elicited. This study was done from December 2019 to December 2020. The main dermoscopic features were generalized erythema (100%), hyperkeratosis with central erosion or ulceration (53.8%), white scar-like patch (41.8%), yellow tears (35.2%), white starburst sign (34.1%), and milia-like cyst (2.2%). We also observed vascular structures, including linear irregular (63.1%), dotted (57.1%), glomerular (38.1%), hairpin (22.6%), and comma-shaped vessels (16.7%). Linear irregular vessels were more commonly demonstrated on the face and upper limbs; while on the lower limbs, hyperkeratosis with erosion and ulceration were the most common finding. Hyperkeratosis with erosions/ulcerations (43.8%) was the most common finding in the papular pattern, linear irregular vessels (56.7%) in the nodular pattern, glomerular vessels (64.3%) was the most common finding in noduloulcerative pattern and linear irregular vessels (71%) was the most common finding in plaque pattern. The dermoscopic features would help in the diagnosis of CL lesions by dermoscopy, especially in endemic areas. There is a good relationship between the dermoscopic features and type of CL lesions.

Ancillary techniques to improve dermoscopy specificity for skin cancer detection

Although the use of dermoscopy has markedly improved both the sensitivity and specificity for skin cancer detection, there is still opportunity for improvement. Ancillary techniques provide additional ways to assess a lesion with the aim of improving our diagnostic ability with little extra cost. Usage of these techniques can strengthen diagnosis and help reduce unnecessary biopsies of benign lesions.

Challenging Patterns of Atypical Dermatofibromas and Promising Diagnostic Tools for Differential Diagnosis of Malignant Lesions

Dermatofibroma (DF) or fibrous histiocytoma is one of the most frequent benign cutaneous soft-tissue lesions, characterized by a post-inflammatory tissue reaction associated with fibrosis of the dermis. Clinically DFs have a polymorphous clinical aspect from the solitary, firm, single nodules to multiple papules with a relatively smooth surface. However, multiple atypical clinicopathological variants of DFs have been reported and, therefore, clinical recognition may become challenging, leading to a more burdensome identification and sometimes to misdiagnosis. Dermoscopy is considered an important tool in DFs diagnosis, as it improves diagnostic accuracy for clinically amelanotic nodules. Although typical dermoscopic patterns are most frequently seen in clinical practice, there have also been some atypical variants described, mimicking some underlying recurrent and sometimes harmful skin afflictions. Usually, no treatment is required, although an appropriate work-up may be necessary in specific cases, such as in the presence of atypical variants or a history of recent changes. This narrative review's aim is to summarize current evidence regarding clinical presentation, positive and differential diagnosis of atypical dermatofibromas and also to raise awareness about the importance of specific characteristics of atypical variants to better differentiate them from malignant conditions.

Dermoscopy of haemosiderotic/aneurysmal dermatofibroma: A morphological study of 110 cases

BACKGROUND

Haemosiderotic and aneurysmal dermatofibromas are uncommon and frequently misdiagnosed lesions, which can be considered as different histopathological stages of the same tumour. A dermoscopic diagnosis testing accuracy has not been performed for these tumours to date.

OBJECTIVES

To determine the diagnostic significance of dermoscopic structures and patterns associated with haemosiderotic/ aneurysmal dermatofibromas in a large series.

METHODS

Dermoscopic images of histopathologically proven cases of 110 haemosiderotic/ aneurysmal dermatofibromas and 501 other tumours were collected. The frequency, sensitivity, specificity, positive predictive value and negative predictive value of the dermoscopic structures and patterns associated with these lesions were calculated.

RESULTS

Haemosiderotic/ aneurysmal dermatofibromas are mostly symmetric lesions (86.5%), and a prominent homogeneous area was present in 100% of them. The presence of vascular structures was very common (86.4%), and dotted vessels were predominant (58.2%). Shiny white structures were seen in 85.5% of lesions, while a peripheral delicate pigment network was present in 69.1%. The most significant pattern was the one composed of a prominent homogeneous area and peripheral delicate pigment network, which showed a specificity of 100% with a relatively good sensitivity (69.1%). All the patterns containing a peripheral delicate pigment network showed very good specificities, positive predictive values and negative predictive values. Those patterns without a peripheral delicate pigment network showed the highest sensitivities, but they showed a significant overlap with other tumours, mainly with melanoma.

CONCLUSIONS

Dermoscopy is helpful in improving the diagnostic accuracy of haemosiderotic/ aneurysmal dermatofibromas. However, there is a considerable dermoscopic overlap between these tumours and melanoma, specifically when the peripheral delicate pigment network is absent.

Dermoscopy practice guidelines for use in telemedicine

Teledermoscopy, or the utilization of dermatoscopic images in telemedicine, can help diagnose dermatologic disease remotely, triage lesions of concern (i.e., determine whether in-person consultation with a dermatologist is necessary, biopsy, or reassure the patient), and monitor dermatologic lesions over time. Handheld dermatoscopes, a magnifying apparatus, have become a commonly utilized tool for providers in many healthcare settings and professions and allows users to view microstructures of the epidermis and dermis. This Dermoscopy Practice Guideline reflects current knowledge in the field of telemedicine to demonstrate the correct capture, usage, and incorporation of dermoscopic images into everyday practice.

Dermoscopy of dermatofibromas: A new perspective

AIM

In dermoscopic studies on dermatofibromas, some publications divide the appearance of lesions into standardised patterns, and some publications classify the clinical appearance of the lesions by comparing them with existing dermatological lesions. This study aims to re-evaluate the dermoscopic findings and patterns of dermatofibromas from a different perspective.

MATERIALS AND METHODS

In this study, 142 lesions of 72 patients were evaluated dermoscopically and their patterns were schematised.

RESULTS

In our study, a total of 15 patterns consisting of main and sub-patterns were created. The most common patterns we detected were pattern 1 (1a: 13.4%, 1b: 8.5%), pattern 8 (8a: 10.6%, 8b: 4.2%) and pattern 2 (2a: 9.2%, 2b: 4.2%), respectively.

CONCLUSION

Patterns of DFs were reclassified while preserving basic patterns. We think that the new sub-patterns and schematisation with this study can contribute to a better understanding of DFs.

Benign Umbilical Tumors Resembling Sister Mary Joseph Nodule

Background:

When physicians see an umbilical nodule, most of them instinctively recall the Sister Mary Joseph nodule. Therefore, dermatologists need to recognize umbilical dermatoses that can be mistaken for the Sister Mary Joseph nodules. This study aimed to describe the different kinds of benign umbilical tumors as well as elucidate the factors that can be used to distinguish the Sister Mary Joseph nodule from these tumors.

Methods:

The “benign umbilical tumor” group included 19 patients, whereas the “Sister Mary Joseph nodule” group comprised 30 patients (2 from our department, 28 from PubMed search). We compared the clinical and dermoscopic findings between 2 groups.

Results:

In the “benign umbilical tumor” group, the most common diagnosis was dermatofibroma (5/19), followed by keloid (3/19), and soft fibroma (3/19). These tumors had various colors (red, brown to black, and flesh colored) and exhibit characteristic surface changes (eg, verrucous changes in epidermal nevi and verrucae). Conversely, most Sister Mary Joseph nodules have an erythematous color, oozing or ulceration on the surface, and nearby satellite lesions. Furthermore, the dermoscopic findings of Sister Mary Joseph nodules showed a polymorphous vascular pattern and a white or milky-red, amorphous area. Benign lesions showed different dermoscopic patterns: pigment networks with white areas (dermatofibromas), thrombosed capillaries (verrucae), and the “pore sign” (epidermal cysts).

Conclusions:

Various cutaneous tumors can be mistaken for the Sister Mary Joseph nodule when they develop on the umbilicus; the clinical and dermoscopic differences found in this study may be useful for establishing a differential diagnosis.

Recent developments in dermoscopy for dermatology

BACKGROUND

Dermoscopy is considered to be a bridge between clinical observation and histopathological examination, allowing the in vivo examination of skin microstructures that are not visible to the naked eye, from the epidermis to the superficial dermis. Dermoscopy has undergone rapid development, witnessing the history from natural light to polarized light, from handheld dermoscopy to videodermoscopy, and from classic dermoscopy to digital dermoscopy. Its application extends from the initial differential diagnosis of pigmented skin diseases (melanocytic and nonmelanocytic) to general dermatology, including appendage (nail and hair) abnormalities and diseases related to infection and inflammation.

AIMS

We aimed to provide the latest developments in dermoscopy from the perspective of handheld dermoscopy, videodermoscopy, fluorescence-advanced videodermatoscopy, polarized transilluminating dermoscopy, and digital dermoscopy.

METHODS

In this review, we searched the PubMed, Embase, Web of Science, and Cochrane Library databases for reviews, case reports, and observational studies on dermoscopy.

RESULTS

We provided an updated review of dermoscopy based on published literature.

CONCLUSION

Dermoscopy is an indispensable diagnostic tool in dermatology, and it is expected to be further developed in the future.

Beyond classic dermoscopic patterns of dermatofibromas: a prospective research study

BACKGROUND

The usual stereotypical dermoscopic pattern associated with dermatofibromas is a pigment network and central white patch. However, this pattern may be difficult to diagnose in some variant cases. We aimed to describe dermoscopic patterns of dermatofibroma according to its histopathological subtypes, with special emphasis on new and rare dermoscopic features.

METHODS

This prospective study, which was conducted between September 2015 and May 2016 in the Department of Dermatology, University Hospital Hassan II, Fez, Morocco, included 100 cases of dermatofibroma confirmed on clinical and histological grounds. Each lesion was scored for classic, previously reported, or new dermoscopic features.

RESULTS

All our Moroccan patients had a dark skin phototype (Fitzpatrick scale types IV and V). A total of 14 morphological dermoscopic structures were distinguished, and 17 dermoscopic patterns were observed, with the most common pattern being the central white patch and peripheral pigment network (21%). New patterns observed in our study were a white ring around an ulceration (6%), a pigment network with a pigmented ring around follicular openings (2%), and a discreet peripheral network and starlike white patch (3%). A patchy network with white patches was significantly noted in atrophic dermatofibroma (p = 0.01); vascularization was described in both aneurysmal and hemosiderotic dermatofibromas (p = 0.002); and a white ring around an ulceration was noted in aneurysmal dermatofibroma (p < 0.001).

CONCLUSIONS

We provide a description of dermoscopic patterns of dermatofibroma according to its histological subtypes in a dark skin phototype, along with a new report of a white ring around an ulceration as a significant pattern in aneurysmal dermatofibroma.

The Role of Color and Morphologic Characteristics in Dermoscopic Diagnosis

IMPORTANCE

Both colors and structures are considered important in the dermoscopic evaluation of skin lesions but their relative significance is unknown.

OBJECTIVE

To determine if diagnostic accuracy for common skin lesions differs between gray-scale and color dermoscopic images.

DESIGN, SETTING, AND PARTICIPANTS

A convenience sample of 40 skin lesions (8 nevi, 8 seborrheic keratoses, 7 basal cell carcinomas, 7 melanomas, 4 hemangiomas, 4 dermatofibromas, 2 squamous cell carcinomas [SCCs]) was selected and shown to attendees of a dermoscopy course (2014 Memorial Sloan Kettering Cancer Center dermoscopy course). Twenty lesions were shown only once, either in gray-scale (n = 10) or color (n = 10) (nonpaired). Twenty lesions were shown twice, once in gray-scale (n = 20) and once in color (n = 20) (paired). Participants provided their diagnosis and confidence level for each of the 60 images. Of the 261 attendees, 158 participated (60.5%) in the study. Most were attending physicians (n = 76 [48.1%]). Most participants were practicing or training in dermatology (n = 144 [91.1%]). The median (interquartile range) experience evaluating skin lesions and using dermoscopy of participants was 6 (13.5) and 2 (4.0) years, respectively.

MAIN OUTCOMES AND MEASURES

Diagnostic accuracy and confidence level of participants evaluating gray-scale and color images. Two separate analyses were performed: (1) an unpaired evaluation comparing gray-scale and color images shown either once or for the first time, and (2) a paired evaluation comparing pairs of gray-scale and color images of the same lesion.

RESULTS

In univariate analysis of unpaired images, color images were less likely to be diagnosed correctly compared with gray-scale images (odds ratio [OR], 0.8; P < .001). Using gray-scale images as the reference, multivariate analyses of both unpaired and paired images found no association between correct lesion diagnosis and use of color images (OR, 1.0; P = .99, and OR, 1.2; P = .82, respectively). Stratified analysis of paired images using a color by diagnosis interaction term showed that participants were more likely to make a correct diagnosis of SCC and hemangioma in color (P < .001 for both comparisons) and dermatofibroma in gray-scale (P < .001).

CONCLUSIONS AND RELEVANCE

Morphologic characteristics (ie, structures and patterns), not color, provide the primary diagnostic clue in dermoscopy. Use of gray-scale images may improve teaching of dermoscopy to novices by emphasizing the evaluation of morphology.

Association of Shiny White Blotches and Strands With Nonpigmented Basal Cell Carcinoma: Evaluation of an Additional Dermoscopic Diagnostic Criterion

IMPORTANCE

Basal cell carcinoma (BCC) is the most common type of skin cancer and is usually nonpigmented. Shiny white structures (SWSs) are frequently present in BCC.

OBJECTIVE

To determine the diagnostic accuracy of various morphologies of SWSs for diagnosis of nonpigmented BCC.

DESIGN, SETTING, AND PARTICIPANTS

Nonpigmented skin tumors, determined clinically and dermoscopically, were identified from a database of lesions consecutively biopsied over a 3-year period (January 2, 2009, to December 31, 2012) from a single dermatology practice. Data analysis was conducted from October 9, 2014, to November 15, 2015. Investigators blinded to histopathologic diagnosis evaluated the polarized dermoscopic images for the presence of SWSs, which were categorized as blotches, strands, short white lines, and rosettes. Measures of diagnostic accuracy for BCC were estimated. Participants included 2375 patients from a dermatologic clinic in Plantation, Florida. Review of the medical records identified 2891 biopsied skin lesions; 457 of these were nonpigmented neoplasms.

MAIN OUTCOMES AND MEASURES

Diagnosis of BCC with dermoscopy compared with all other diagnoses combined was the primary outcome; the secondary outcome was diagnosis of BCC compared with amelanotic melanoma. We calculated diagnostic accuracy measured as odds ratios (ORs), sensitivity, and specificity of shiny white blotches and/or strands for the diagnosis of BCC.

RESULTS

Of the 457 nonpigmented neoplasms evaluated, 287 (62.8%) were BCCs, 106 (23.2%) were squamous cell carcinoma, 39 (8.5%) were lichen planus-like keratosis, 21 (4.6%) were melanomas, and 4 (0.9%) were nevi. The prevalence of SWSs was 49.0% (n = 224). In multivariate analysis (reported as OR [95% CI]) controlling for age, sex, and anatomical location, the presence of any SWS was associated with a diagnosis of BCC (2.3 [1.5-3.6]; P < .001). Blotches (6.3 [3.6-10.9]; P < .001), strands (4.9 [2.9-8.4]; P < .001), and blotches and strands together (6.1 [3.3-11.3]; P < .001) were positively associated with BCC. Shiny white blotches and strands together had a diagnostic sensitivity of 30% and specificity of 91%.

CONCLUSIONS AND RELEVANCE

The combined presence of shiny white blotches and strands is associated with high diagnostic specificity for nonpigmented BCC.

Dermoscopic features of livedoid vasculopathy

Livedoid vasculopathy (atrophie blanche) is a form of thrombotic vasculopathy. It is characterized by small ulcers that become crusted, and heal after several months to produce white atrophic scars. The most commonly affected sites are the lower legs, in particular the dorsum of the feet and ankles. To date, the dermoscopic features of livedoid vasculopathy have not been clearly described in the literature. In this observational study, we sought to evaluate the dermoscopic patterns of livedoid vasculopathy and determine whether the dermoscopic features are associated with certain histopathological characteristics. We evaluated 9 patients with livedoid vasculopathy by dermoscopy. Skin biopsy specimens were stained with hematoxylin and eosin for histopathologic examination, and dermoscopic features were correlated with histopathological characteristics. In the majority of patients with livedoid vasculopathy, examination with dermoscopy revealed central crusted ulcers or ivory white areas associated with peripheral pigmentation in a reticular pattern. In addition, increased vascular structures including linear and glomerular vessels were found. On histopathological examination, the central ivory white areas correlated with dermal fibrosis, the reticular pigmentation corresponded to epidermal basal layer hyperpigmentation or melanin within melanophages in the dermal papillae, and the vascular structures correlated with dilatation and proliferation of capillaries in the upper dermis. In summary, the most common dermoscopic features of livedoid vasculopathy identified in this study were central crusted ulcers or ivory white scar-like areas associated with peripheral reticular pigmentation and increased vascular structures. The characterization of dermoscopic criteria for livedoid vasculopathy may improve the accuracy in the clinical diagnosis and follow-up of this disease.

Vascular structures in dermoscopy

Dermoscopy is an aiding method in the visualization of the epidermis and dermis. It is usually used to diagnose melanocytic lesions. In recent years, dermoscopy has increasingly been used to diagnose non-melanocytic lesions. Certain vascular structures, their patterns of arrangement and additional criteria may demonstrate lesion-specific characteristics. In this review, vascular structures and their arrangements are discussed separately in the light of conflicting views and an overview of recent literature.

Standardization of terminology in dermoscopy/dermatoscopy: Results of the third consensus conference of the International Society of Dermoscopy

BACKGROUND

Evolving dermoscopic terminology motivated us to initiate a new consensus.

OBJECTIVE

We sought to establish a dictionary of standardized terms.

METHODS

We reviewed the medical literature, conducted a survey, and convened a discussion among experts.

RESULTS

Two competitive terminologies exist, a more metaphoric terminology that includes numerous terms and a descriptive terminology based on 5 basic terms. In a survey among members of the International Society of Dermoscopy (IDS) 23.5% (n = 201) participants preferentially use descriptive terminology, 20.1% (n = 172) use metaphoric terminology, and 484 (56.5%) use both. More participants who had been initially trained by metaphoric terminology prefer using descriptive terminology than vice versa (9.7% vs 2.6%, P < .001). Most new terms that were published since the last consensus conference in 2003 were unknown to the majority of the participants. There was uniform consensus that both terminologies are suitable, that metaphoric terms need definitions, that synonyms should be avoided, and that the creation of new metaphoric terms should be discouraged. The expert panel proposed a dictionary of standardized terms taking account of metaphoric and descriptive terms.

LIMITATIONS

A consensus seeks a workable compromise but does not guarantee its implementation.

CONCLUSION

The new consensus provides a revised framework of standardized terms to enhance the consistent use of dermoscopic terminology.

Hemosiderotic dermatofibroma: clinical and dermoscopic presentation mimicking melanoma

BACKGROUND

Dermatofibromas are common benign skin neoplasms.

MAIN OBSERVATIONS

The authors report the clinical, dermoscopic and histopathological features of a hemosiderotic dermatofibroma mimicking melanoma in an 85-year-old woman.

CONCLUSIONS

Atypical dermoscopic patterns may prove difficult to differentiate from melanocytic lesions, and because of its polymorphic, melanoma-like presentation, definite diagnosis of hemosiderotic dermatofibroma can be reached by histopathological examination.

Pink lesions

Dermoscopy (dermatoscopy or surface microscopy) is an ancillary dermatologic tool that in experienced hands can improve the accuracy of diagnosis of a variety of benign and malignant pigmented skin tumors. The early and more accurate diagnosis of nonpigmented, or pink, tumors can also be assisted by dermoscopy. This review focuses on the dermoscopic diagnosis of pink lesions, with emphasis on blood vessel morphology and pattern. A 3-step algorithm is presented, which facilitates the timely and more accurate diagnosis of pink tumors and subsequently guides the management for such lesions.

Multiple dermatofibromas: dermoscopic patterns

Dermatofibromas are benign skin lesions that consist of pigmented papules or nodules. They produce the dimple sign when laterally squeezed and are usually found on the legs. These clinical features lead to the diagnosis in most cases. However, the differential diagnosis with other lesions, such as atypical nevi and melanoma can be difficult, and the dermoscopy may help the diagnosis. There are several dermoscopic patterns associated with dermatofibromas, the most common being a central white scar like patch with delicate pigment network at the periphery. This article describes the case of a patient who had eleven clinically similar dermatofibromas, with four distinct patterns when submitted to dermoscopic examination.

Typical and atypical dermoscopic presentations of dermatofibroma

BACKGROUND

Dermatofibroma is a common skin neoplasm that is usually easy to recognize, but in some cases its differentiation from melanoma and other tumours may be difficult.

OBJECTIVE

To describe the dermoscopic features of dermatofibromas, with special emphasis on the characteristics of atypical patterns, and to calculate pattern frequency according to the patients age and gender, anatomical site and histopathological subtype.

METHODS

Two groups of patients were consecutively seen, one with dermatofibromas that were surgically excised because of clinically and/or dermoscopically equivocal aspects or following patient request, and another with non-equivocal dermatofibromas. Each lesion was scored for previously reported global dermoscopic patterns and for additional features.

RESULTS

A typical pattern was observed in 92 of 130 (70.8%) lesions, whereas an atypical pattern, that we named the 'non Dermatofibroma (DF)-like' pattern, was seen in 38 of 130 (29.2%). Atypical dermatofibromas showed features reminiscent of different conditions, such as melanoma in 21(16.2%) cases, vascular tumour in six (4.6%), basal cell carcinoma in five (3.8%), collision tumour in three (2.3%) and psoriasis in three (2.3%). A significant association was found between the 'melanoma-like' pattern/'vascular tumour-like' pattern and males, whereas a trend was observed between the above-mentioned patterns and hemosiderotic/aneurysmal DFs. 'Peripheral pigment network and central white scar-like patch' pattern was found associated with females and classic histopathological variant of DF.

CONCLUSION

Dermatofibromas may display different morphological faces. The typical dermoscopic patterns allow a confident diagnosis, whereas a full surgical excision is always recommended in all doubtful cases.

Chrysalis and negative pigment network in Spitz nevi

Chrysalis, also named shiny white streaks, are white, linear structures only visible with polarized dermoscopy. They have been reported in several tumors included melanomas and Spitz nevi, and their histological substrate is believed to be dermal fibrosis. We have performed a correlation study between the dermoscopic and the histopathological features of 9 Spitz nevi. Chrysalis were present in 4 Spitz nevi (44%) and in all of them there was a high degree of fibroplasia. In one case, chrysalis, evident at the center of the lesion, progressively merged with negative pigment network at the periphery. We suggest that chrysalis and negative pigment network are manifestations of the same histopathological finding: increased collagen occurring at different levels of the dermis.

White shiny structures: dermoscopic features revealed under polarized light

BACKGROUND

White shiny structures, including white shiny lines, white shiny areas and rosettes, are features only observed under polarized dermoscopy (PD).

OBJECTIVE

To evaluate the prevalence of the varied morphologies of white shiny structures in melanoma, basal cell carcinoma (BCC), squamous cell carcinoma (SCC), actinic keratosis (AK) and lichen planus-like keratosis (LPLK).

METHODS

Retrospective study using dermoscopic images of biopsy-proven melanoma, BCC, SCC, AK and LPLK.

RESULTS

A total of 538 lesions were assessed under PD. One or more types of white shiny structures were observed in 38.7% of study lesions (208/538). BCCs were significantly more likely to display a combination of white shiny areas and white shiny lines (short lines and/or ill-defined strands) (31.9%; 61/191) than any other lesions (P<0.001). BCC were more likely than other lesions to have white shiny lines distributed without any organized pattern (P<0.001). Lines in melanoma were significantly more likely than other lesion types to be oriented orthogonally (P<0.001). When white shiny lines were present, melanomas were significantly more likely than other lesions to exhibit short discrete white lines (P<0.001). Rosettes were significantly more likely to be observed in actinic tumours than other lesions (P<0.001).

CONCLUSION

The presence of white shiny lines of any length accompanied by white shiny areas is most suggestive of a diagnosis of BCC (P<0.001). Melanomas are more likely to display short white shiny lines in an orthogonal distribution (P<0.001) and without white shiny areas. Actinic tumours are most likely to exhibit rosettes (P<0.001).

Dermoscopy of pyogenic granuloma: a morphological study

BACKGROUND

Pyogenic granuloma is a common, benign, vascular lesion of the skin and mucous membranes which is a simulator of amelanotic/hypomelanotic melanoma and other tumours.

OBJECTIVES

To determine the diagnostic significance of dermoscopic structures and patterns associated with pyogenic granulomas in a large series of cases.

METHODS

Digital dermoscopic images of histopathologically proven cases of 122 pyogenic granulomas and 140 other tumours (28 amelanotic melanomas, seven melanoma metastases, 22 basal cell carcinomas and 83 other tumours) were collected from university hospitals in Spain, Italy, Austria and Turkey. The frequency, sensitivity, specificity, positive predictive value, negative predictive value, intraobserver agreement and interobserver agreement of the dermoscopic structures and patterns associated with pyogenic granulomas were calculated.

RESULTS

Vascular structures were observed in 45% of pyogenic granulomas (sensitivity of 45·1% and specificity of 17·9%; both P < 0·001). Seven exclusive patterns were made up from the combination of the structures 'reddish homogeneous area' (RHA), 'white collarette' (WC), 'white rail lines' (WRL) and 'vascular structures' (VS). The pattern composed of RHA, WC and WRL showed the highest sensitivity (22·1%; P < 0·001) and a specificity of 100% (P < 0·001) for pyogenic granulomas. Two other patterns (RHA + WC and RHA + WC + WRL + VS) showed 100% specificity when compared with melanoma (P < 0·001 and P < 0·05, respectively).

CONCLUSIONS

Even though some dermoscopic patterns are useful in the recognition of pyogenic granulomas, dermoscopy is not a substitute for histology, mostly when vessels are present, as melanoma cannot be ruled out.