Benign Melanocytic Lesions Research Articles

499 miR-204-5p mimic application induces BCL2 and SIRT1 elevated expression levels in lungs and BCL2 elevated levels in kidneys of melanoma B16-bearing mice

MicroRNAs are small non-coding RNA molecules involved in the epigenetic regulation of carcinogenesis. miR-204-5p was shown to be among the most downregulated miRs in melanoma versus benign melanocytic lesions. SIRT1 as a gene target of miR-204-5p regulates proliferation, apoptosis, migration of cancer cells whereas BCL2 is a well known by it’s antiapoptotic functions. Therefore melanoma B16-bearing mice were treated by synthetic mimic of miR-204-5p administered intraperitoneally once in three days within two weeks.

Recurrence of a Cellular Blue Nevus with Satellitosis-A Diagnostic Pitfall with Clinical Consequences.

Blue nevus is a benign melanocytic lesion, typically asymptomatic and of unknown etiology. Several histologic and clinical variants have been distinguished, the most frequent being common blue nevus, cellular blue nevus, and combined blue nevus. Although melanocytic nevi with a satellite lesion are usually suggestive of locally advanced malignant melanoma, very few cases of blue nevi with satellite lesions have been reported. The diagnosis of common or cellular blue nevi is generally straightforward; however, the presence of structures such as irregular edges or satellitosis are highly suggestive for malignancy, and differential diagnoses such as locally advanced malignant melanoma and malignant blue nevus should be considered. Recurrent blue nevi can display atypical features not seen in the primary lesion, such as pleomorphism and mitotic activity. They usually tend to follow a benign course; however, in some cases, recurrence may indicate malignant transformation. We here report the unique case of a 64-year-old woman with a recurrent cellular blue nevus accompanied by satellite lesions. Such a biological behavior resulting in a clinical presentation as a melanoma-like lesion is a rarity in blue nevus and has not been described before.

Hyperspectral Imaging for Non-invasive Diagnostics of Melanocytic Lesions.

Malignant melanoma poses a clinical diagnostic problem, since a large number of benign lesions are excised to find a single melanoma. This study assessed the accuracy of a novel non-invasive diagnostic technology, hyperspectral imaging, for melanoma detection. Lesions were imaged prior to excision and histopathological analysis. A deep neural network algorithm was trained twice to distinguish between histopathologically verified malignant and benign melanocytic lesions and to classify the separate subgroups. Furthermore, 2 different approaches were used: a majority vote classification and a pixel-wise classification. The study included 325 lesions from 285 patients. Of these, 74 were invasive melanoma, 88 melanoma in situ, 115 dysplastic naevi, and 48 non-dysplastic naevi. The study included a training set of 358,800 pixels and a validation set of 7,313 pixels, which was then tested with a training set of 24,375 pixels. The majority vote classification achieved high overall sensitivity of 95% and a specificity of 92% (95% confidence interval (95% CI) 0.024-0.029) in differentiating malignant from benign lesions. In the pixel-wise classification, the overall sensitivity and specificity were both 82% (95% CI 0.005-0.005). When divided into 4 subgroups, the diagnostic accuracy was lower. Hyperspectral imaging provides high sensitivity and specificity in distinguishing between naevi and melanoma. This novel method still needs further validation.

Genetic and Methylation Analysis of CTNNB1 in Benign and Malignant Melanocytic Lesions.

Simple SummaryRecurrent CTNNB1 exon 3 mutations have been recognized in the distinct group of melanocytic tumors showing deep penetrating nevus-like morphology and in 1–2% of advanced melanoma. We performed a detailed genetic analysis of difficult-to-classify nevi and melanomas with CTNNB1 mutations and found that benign tumors (nevi) show characteristic morphological, genetic and epigenetic traits, which distinguish them from other nevi and melanoma. Malignant CTNNB1-mutant tumors (melanoma) demonstrated a different genetic profile, grouping clearly with other non-CTNNB1 melanomas in methylation assays. To further evaluate the role of CTNNB1 mutations in melanoma, we assessed a large cohort of clinically sequenced melanomas, identifying 38 tumors with CTNNB1 exon 3 mutations, including recurrent S45 (n = 13, 34%), G34 (n = 5, 13%), and S27 (n = 5, 13%) mutations. Locations and histological subtype of CTNNB1-mutated melanoma varied; none were reported as showing deep penetrating nevus-like morphology. The most frequent concurrent activating mutations were BRAF V600 (55%) and NRAS Q61 (34%).Melanocytic neoplasms have been genetically characterized in detail during the last decade. Recurrent CTNNB1 exon 3 mutations have been recognized in the distinct group of melanocytic tumors showing deep penetrating nevus-like morphology. In addition, they have been identified in 1–2% of advanced melanoma. Performing a detailed genetic analysis of difficult-to-classify nevi and melanomas with CTNNB1 mutations, we found that benign tumors (nevi) show characteristic morphological, genetic and epigenetic traits, which distinguish them from other nevi and melanoma. Malignant CTNNB1-mutant tumors (melanomas) demonstrated a different genetic profile, instead grouping clearly with other non-CTNNB1 melanomas in methylation assays. To further evaluate the role of CTNNB1 mutations in melanoma, we assessed a large cohort of clinically sequenced melanomas, identifying 38 tumors with CTNNB1 exon 3 mutations, including recurrent S45 (n = 13, 34%), G34 (n = 5, 13%), and S27 (n = 5, 13%) mutations. Locations and histological subtype of CTNNB1-mutated melanoma varied; none were reported as showing deep penetrating nevus-like morphology. The most frequent concurrent activating mutations were BRAF V600 (n = 21, 55%) and NRAS Q61 (n = 13, 34%). In our cohort, four of seven (58%) and one of nine (11%) patients treated with targeted therapy (BRAF and MEK Inhibitors) or immune-checkpoint therapy, respectively, showed disease control (partial response or stable disease). In summary, CTNNB1 mutations are associated with a unique melanocytic tumor type in benign tumors (nevi), which can be applied in a diagnostic setting. In advanced disease, no clear characteristics distinguishing CTNNB1-mutant from other melanomas were observed; however, studies of larger, optimally prospective, cohorts are warranted.

Application of immunohistochemical staining of PRAME in differential diagnosis between melanoma and melanocytic nevus

Objective: To investigate the diagnostic value of preferentially expressed antigen in melanoma (PRAME) in differential diagnosis of benign and malignant cutaneous melanocytic lesions. Methods: Fifty-nine cases of melanoma (50 cases of skin primary melanoma, and 9 cases of metastatic melanoma) and 48 cases of melanocytic nevus (40 cases of common nevus and 8 cases of dysplastic nevus) were subject to PRAME immunohistochemistry staining.The difference of PRAME expression between melanoma and melanocytic nevus was analyzed. Results: Among the 50 patients with primary cutaneous melanoma, there were 23 males and 27 females ranging in age from 33 to 87 years (average age 62.4 years, median age 64.5 years). Among the 9 metastatic melanoma there were 7 males and 2 females ranging in age from 40 to 82 years (average age 64 years, median age 65 years). Twenty-six cases (26/50, 52.0%) of cutaneous primary melanoma and 4 cases (4/9) of metastatic melanoma showed diffuse positive PRAME staining. 40 cases (40/40, 100%) of common nevus and 8 (8/8) cases of dysplastic nevus were PRAME negative. Compared with melanocytic nevus group, the melanoma group included more cases with diffuse positive PRAME staining (P<0.05). The sensitivity and specificity of using PRAME to differentiate primary cutaneous melanoma from melanocytic nevus in the cohort is 52.0% and 100%. Conclusions: There is a significant difference in the expression of PRAME between melanoma and melanocytic nevus.Thus, PRAME can be used as an auxiliary diagnostic tool for differentiating benign from malignant cutaneous lesions.

Immunohistochemistry in melanocytic lesions: Updates with a practical review for pathologists.

This review provides a summary of the immunohistochemical markers pertinent to the diagnosis of melanocytic lesions. There is considerable morphologic overlap between benign and malignant melanocytic lesions, and given the significant differences in clinical management, the diagnostic workup becomes crucial. Immunohistochemistry aids in the distinction between various melanocytic proliferations and recent contributions to the literature have furthered our optimization of panels in the diagnostic workup. In recent years, SOX10 has been considered as the optimal marker for melanocytic lesions given the similar sensitivity but higher specificity than S100. HMB-45 is less sensitive than S100 but demonstrates utility in confirmation of deceptively banal small cell and nevoid melanoma variants where deep nests of melanocytes are highlighted. Melan-A (MART-1) and MiTF show similar sensitivity to S100 however there is a lack of expression in spindle cell and desmoplastic melanomas.

PRAME immunohistochemistry for melanoma diagnosis: A STARD-compliant diagnostic accuracy study.

Preferentially expressed antigen in melanoma (PRAME) is a tumor-associated antigen that is frequently expressed in cutaneous melanoma and can be evaluated by immunohistochemistry. Earlier studies on PRAME utilized case-control study designs that may misestimate diagnostic accuracy and lack generalizability. Using retrospective cohort selection, a cross-sectional study of diagnostic accuracy of PRAME was conducted according to standards for reporting diagnostic accuracy studies requirements. Mean PRAME positive fraction was higher in 42 malignant melanocytic lesions than 101 benign melanocytic lesions (0.71 ± 0.30 vs. 0.13 ± 0.20, p < 0.01). Receiver operating characteristic curve showed the test was effective (area under the curve=0.90). Global PRAME 4+ scores (>75%) were associated with sensitivity of 0.63, specificity of 0.97, accuracy of 0.87, and excellent interrater concordance (Kappa=0.83). Lower cutoffs for PRAME of 2+ (>25%) and 3+ (>50%) produced higher joint sensitivity/specificity (Youden index) than PRAME 4+, but lower accuracy. PRAME as it is used in clinical practice is an effective test for melanoma. PRAME is best used as an ordinal variable to calculate the posttest probability of melanoma. PRAME ≤25% (0/1+) favors nevus, PRAME 26%-75% (2/3+) is noncontributory, and PRAME >75% (4+) favors melanoma.

Multicenter prospective clinical trial of molecular genetic markers for non-invasive differential diagnosis of benign and malignant melanocytic skin lesions.

e21581 Background: Improving the accuracy of non-invasive diagnosis of skin tumors is becoming an urgent problem, given the clear increase in the incidence of melanoma in many countries. Dermoscopy and examination by an experienced dermatologist can reduce the NNE to 5–10 per melanoma (M) detected, however, achieving even this, clearly suboptimal, rate requires a long specialist training. Methods: We report results of prospective nonrandomized trial evaluating sensitivity and specificity of RNA profiling of cytological samples from adhesive transparent patches (ATP) applied to skin lesions. Routine pathology reports were obtained for all surgery samples. RNA extracted from ATP specimens (N = 126) was tested for mRNA expression of PRAME and LINC00518 genes. GAPDH was used as a reference gene. Sample was considered marker-positive if either PRAME or LINC00518 expression was detected. Results: Between June 2021 and November 2021, 126 pts undegoing excisional biopsy of skin lesions were included in the study at 5 centers. On pathology, invasive M was detected in 49 (38.9%) patients (mean Breslow thickness was 2.41 mm [95%CI 1,44 to 3.37]), M in situ in 6 (4.8%), non-melanoma skin cancer in 4 (3.2%) and dysplastic nevus in 56 (44.4%). In the day of preplanned excision ATP was applied to the target lesion for 5–6 min and sent to the central lab. Amplifiable mRNA was found in all 126 ATP samples. 82 samples of 126 (65,1%) tested marker-positive. Sensitivity of RNA profiling for detection of skin cancers reached 88.14% (95% CI 77.07% – 95.09%), while specificity was only 53.85% (41.03% – 66.30%), with PPV of 63.41% (56.74% – 69.61%), NPV of 83.33% (70.65% – 91.22%) and accuracy of 70.16% (61.29% – 78.04%). Among the seven false negative results there were 3 M in situ and 4 invasive M. Conclusions: RNA profiling of skin ATP specimens is feasible and has high sensitivity but rather low specificity. Randomized studies are needed to evaluate if this technique can add anything to dermoscopy or other noninvasive diagnostic modalities. Clinical trial information: NCT04353050. [Table: see text]

Expression of endoglin, CD105, in conjunctival melanocytic nevi: Is it suspicious like in thyroidology? Oculi plus vident quam oculus?

The aim of this study was to evaluate the expression of endoglin and its correlation with histopathological and clinical findings in conjunctival nevi. The study included archival formalin-fixed, paraffin-embedded tissue sections of 44 patients with conjunctival nevi. Immunohistochemical staining for CD105 had been performed with monoclonal mouse antihuman CD105 antibodies. The intratumoral microvessel density for quantification of tumoral vascularization had been determined by this marker. The expression of CD105 was positive in 30 (68.2%) cases. There was a statistically significant difference in the level of CD105 expression regarding the histological type of nevus (p=0.03) and intralesional cysts status (p=0.02). Spearman's rho (ρ -0.316) revealed a significant negative correlation between the expression of endoglin and the histological type of nevus (p=0.03) and between the expression of endoglin and the presence of intralesional cysts (ρ -0.380, p=0.01). This study suggests that endoglin could be a useful diagnostic and prognostic marker in differentiating between benign and malignant melanocytic ocular lesions.

Reduced fluence photodynamic therapy for subretinal fluid in choroidal nevus

Choroidal nevus is a benign melanocytic lesion of the posterior uvea. Visual symptoms in choroidal nevus are most commonly secondary to serous neurosensory detachment in upto 50% cases. Here, we describe a case of symptomatic perifoveal Choroidal Nevus with sub-retinal fluid, which was treated with Reduced Fluence Photodynamic Therapy.

Subungual melanoma with blue naevus-like morphological features: a clinicopathological retrospective analysis of nine cases

Melanocytic lesions in the nail apparatus are often challenging. Both subungual melanomas (SUM) and blue naevus of the nail are very rare. Occasionally, melanomas may mimic blue naevus histologically. Benign and malignant blue melanocytic lesions are commonly associated with G protein mutations, a distinct abnormality not associated with conventional subungual melanomas. We describe the clinical, histological and immunohistochemical features of nine cases of SUM with blue naevus-like morphological features. Mutations in exon 4 and 5 of GNAQ and GNA11 were investigated in two cases, which showed no mutations. RNA-seq of one case revealed unknown mutations along with mutations in ATM, METK and ARID1A. Our study delineates a variant of SUM that mimics blue naevus. Awareness of this pitfall is important when evaluating heavily pigmented lesions around the nail in order to avoid misdiagnosis. Appropriate sampling of subungual lesions and clinicopathological correlation are paramount to reach the correct diagnosis.

Clear Cell Neoplasms of Salivary Glands: A Diagnostic Challenge.

This review focuses on the heterogenous group of clear cell neoplasms of salivary glands and attempts to identify major differential diagnostic features. Within the head and neck region, clear cells are found most commonly in salivary gland tumors, but may also be seen in tumors of squamous or odontogenic epithelial origin, primary or metastatic carcinomas, benign or malignant melanocytic lesions, or benign or malignant mesenchymal tumors. Clear cells occur fairly commonly among a wide variety of salivary gland neoplasms, but mostly they constitute only a minor component of the tumor cell population. Clear cells represent a major diagnostic feature in two salivary gland neoplasms, epithelial-myoepithelial carcinoma and hyalinizing clear cell carcinoma. In addition, salivary gland neoplasms composed predominantly of clear cells could also include clear cell variants of other salivary neoplasms, such as mucoepidermoid carcinoma and myoepithelial carcinoma, but their tumor type-specific histologic features may only be available in limited nonclear cell areas of the tumor. Diagnosing predominantly clear cell salivary gland tumors is difficult because the immunoprofiles and morphologic features may overlap and the same tumor entity may also have a wide range of other histologic presentations. Many salivary gland tumors are characterized by tumor type-specific genomic alterations, particularly gene fusions of the ETV6 gene in secretory carcinoma, the MYB and MYBL1 genes in adenoid cystic carcinoma, the MAML2 gene in mucoepidermoid carcinoma, the EWSR1 gene in hyalinizing clear cell carcinoma, and others. Thus, along with conventional histopathologic examination and immunoprofiling, molecular and genetic tests may be important in the diagnosis of salivary gland clear cell tumors by demonstrating genetic alterations specific to them.

Hotspot analysis by confocal microscopy can help to differentiate challenging melanocytic skin lesions.

Some melanocytic lesions do not present enough clinical and dermoscopic features to allow ruling out a possible melanoma diagnosis. These "doubtful melanocytic lesions" pose a very common and challenging scenario in clinical practice and were selected at this study for reflectance confocal microscopy evaluation and subsequent surgical excision for histopathological diagnosis. The study included 110 lesions and three confocal features were statistically able to distinguish benign melanocytic lesions from melanomas: "peripheral hotspot at dermo-epidermal junction", "nucleated roundish cells at the dermo-epidermal junction" and "sheet of cells". The finding of a peripheral hotspot (atypical cells in 1mm2) at the DEJ is highlighted because has not been previously reported in the literature as a confocal feature related to melanomas.

Immunohistochemistry for Preferentially Expressed Antigen in Melanoma in the Differential Diagnosis of Melanocytic Lesions of the Nail Apparatus.

Nail unit melanocytic lesions present a unique set of diagnostic challenges because of the unfamiliarity with clinical assessment and the lack of experience with histologic examination. Because the first surgical specimen received in the pathology laboratory is typically small, sometimes suboptimal biopsy, the distinction between melanoma and its histologic mimics can be difficult. For this reason, there has been a continued interest in the development of ancillary markers that may assist in the differential diagnosis of nail unit melanocytic lesions. Upregulation of preferentially expressed antigen in melanoma (PRAME) has been reported to be a common event in melanomas, and PRAME immunohistochemistry has been shown to be helpful in evaluating various melanocytic neoplasms. In this study, we evaluated PRAME protein expression in a series of nail unit melanocytic lesions. Twenty-five nail unit melanomas (including small biopsy and amputation specimens) and 32 control benign melanocytic lesions were retrospectively retrieved. Nuclear PRAME staining was scored as percentage and intensity labeling. All melanoma cases showed the nuclear expression of PRAME, which was usually diffuse and strong. In specimens where the neoplastic cells are limited in number, the staining was restricted to the tumor cells, corresponding to the initial H&E impression. All control cases were negative for PRAME expression. PRAME expression is helpful in distinguishing between melanomas and other nail unit melanocytic lesions. This antibody also proved to be diagnostically valuable in detecting melanoma cells in small specimens with minimal disease.

Digital dermoscopy monitoring of melanocytic lesions: Two novel calculators combining static and dynamic features to identify melanoma.

Early diagnosis is the most effective intervention to improve the prognosis of cutaneous melanoma. Even though the introduction of dermoscopy has improved the diagnostic accuracy, it can still be difficult to distinguish some melanomas from benign melanocytic lesions. Digital dermoscopy monitoring can identify dynamic changes of melanocytic lesions: To date, some algorithms were proposed, but a universally accepted one is still lacking. To identify independent predictive variables associated with the diagnosis of cutaneous melanoma and develop a multivariable dermoscopic prediction model able to discriminate benign from malignant melanocytic lesions undergoing digital dermoscopy monitoring. We collected dermoscopic images of melanocytic lesions excised after dermoscopy monitoring and carried out static and dynamic evaluations of dermoscopic features. We built two multivariable predictive models based on logistic regression and random forest. We evaluated 173 lesions (65 cutaneous melanomas and 108 nevi). Forty-two melanomas were in situ, and the median thickness of invasive melanomas was 0.35 mm. The median follow-up time was 9.8 months for melanomas and 9.1 for nevi. The logistic regression and random forest models performed with AUC values of 0.87 and 0.89, respectively, were substantially higher than those of the static evaluation models (ABCD TDS score, 0.57; 7-point checklist, 0.59). Finally, we built two risk calculators, which translate the proposed models into user-friendly applications, to assist clinicians in the decision-making process. The present study demonstrates that the integration of dynamic and static evaluations of melanocytic lesions is a safe approach that can significantly boost the diagnostic accuracy for cutaneous melanoma. We propose two diagnostic tools that significantly increase the accuracy in discriminating melanoma from nevi during digital dermoscopy monitoring.

Preferentially expressed antigen in melanoma immunohistochemistry as an adjunct for differential diagnosis in acral lentiginous melanoma and acral nevi

Preferentially expressed antigen in melanoma (PRAME) has shown promising utility in distinguishing benign melanocytic lesions from melanomas, but knowledge of its expression pattern in acral lentiginous melanoma (ALM) and acral nevi (ANs) is limited. Immunohistochemical expression of PRAME was examined in 75 ALMs and 34 ANs. The clinical and histopathologic characteristics of patients with ALM were collected. PRAME was immunoreactive in 89.3% (67/75) of ALMs, but entirely negative in 94.1% (32/34) of ANs. When staining at least 50% of lesional melanocytes was determined as positivity, the sensitivity and specificity of PRAME for distinguishing ALM from ANs were 69.3% and 100%, respectively. Seventy-one cases of ALMs had tumor cells in the epidermis; 71.8% (51/71) of them showed positive for PRAME. By contrast, 61 ALMs had tumor cells in the dermis; 65.6% (40/61) exhibited positive expression. Twenty-nine of 39 (74.4%) epithelioid cell ALMs were observed to be positive for PRAME. By comparison, 63.8% (23/36) of ALMs with spindle tumor cells were positive for PRAME. However, PRAME positive expression was not associated with any clinical and histopathologic characteristics of patients with ALM, including Breslow thickness, ulcer, cytomorphology, lymph node metastasis, or tumor-infiltrated lymphocytes (TILs). Nevertheless, we observed that 82.6% (19/23) of ALMs with lymph node involvement at diagnosis expressed PRAME, compared with 57.6% (20/35) of those without. In summary, PRAME immunohistochemistry can serve as a helpful adjunct in the differential diagnosis of ALMs and ANs with good sensitivity and high specificity. Additionally, PRAME tends to have a higher positive rate in epidermal melanocytes than in the dermisand is inclined to express in epithelioid cells than in spindle cells of ALMs.

Congenital melanocytic nevus becoming evident at puberty.

Among the stimuli capable of causing nevi and influencing the production of melanin there are, in addition to genetic factors, phototype, immune suppression, sun radiation, even hormonal factors (1). Clinical evidence of this is the exceptional occurrence of melanoma before puberty, the increase in moles and melanic production in conjunction with puberty and pregnancy, and the regression of many moles in the last decades of life (4). However, there are also experimental studies that demonstrate the role of hormones and in particular of estrogens in the appearance of benign and malignant melanocytic lesions. Prior to the discovery of estrogen receptors (ER) beta, studies with ER alpha had not demonstrated a role of estrogen on the pathophysiology of benign and malignant melanocytic lesions (8). After the discovery of ER beta, it was found that these receptors are present in all melanocytic lesions, both benign and malignant (6). As regards benign melanocytic lesions, ER beta are particularly present in congenital (2) and in Spitz-Reed nevi (7). The vulvar melanocytic nevus of the actual report is probably a poorly pigmented congenital junc-tional nevus, also due to the non-photo-exposed site, which has suddenly become visible due to the effect of peripuberal hormonal stimuli. There is another very similar example in clinical practice, namely the congenital melanocytic nevus not evident at birth (3). Melanocytic nevi that appear in the first year of life are usually thought to be congenital (5). However, many of these nevi are really present at birth, but not visible because they are junctional and non-pigmented (3). The accuracy of this hypothesis is demonstrated by the fact that at their first appearance these nevi already have many times a diameter greater than one centimeter and that after becoming evident due to the pigmentation generally induced by the first sun exposures they never show autonomous growth.

Variability in the Histopathological Diagnosis of Non-Melanocytic Lesions Excised to Exclude Melanoma.

The differential diagnosis of lesions excised to exclude melanoma include a variety of benign and malignant melanocytic and non-melanocytic lesions. We examined the variability between pathologists in diagnosing non-melanocytic lesions. As part of a larger study prospectively examining the diagnosis of lesions excised to exclude melanoma in 198 patients at a primary care skin cancer clinic in Newcastle, Australia, we compared diagnosis made by 5 experienced dermatopathologists, of 44 non-melanocytic lesions in 44 patients aged 22-90. Forty-four lesions (out of 217 in total) were non-melanocytic. Among the 5 pathologists who examined each case there was marked variability in the terminology used to diagnose each case. The most common variability was found between seborrheic keratosis, large cell acanthoma, solar lentigo, and lichenoid keratosis. The diagnosis made by the majority of the pathologists was deemed to be the reference diagnosis. Versus majority diagnosis, 4% of benign lesions were considered malignant, and 7% of malignant diagnoses were considered as benign. The different terminology adopted and lack of consensus in the diagnosis of these non-melanocytic lesions in this setting suggests that training AI systems using gold standards may be problematic. We propose a new management classification scheme called MOLEM (Management of Lesions Excised to exclude Melanoma) which expands the previously described MPATH-dx to include non-melanocytic lesions.

Dermoscopy Images Enhancement via Multi-Scale Morphological Operations

Skin dermoscopy images frequently lack contrast caused by varying light conditions. Indeed, often low contrast is seen in dermoscopy images of melanoma, causing the lesion to blend in with the surrounding skin. In addition, the low contrast prevents certain details from being seen in the image. Therefore, it is necessary to design an approach that can enhance the contrast and details of dermoscopic images. In this work, we propose a multi-scale morphological approach to reduce the impacts of lack of contrast and to enhance the quality of the images. By top-hat reconstruction, the local bright and dark features are extracted from the image. The local bright features are added and the dark features are subtracted from the image. In this way, images with higher contrast and detail are obtained. The proposed approach was applied to a database of 236 color images of benign and malignant melanocytic lesions. The results show that the multi-scale morphological approach by reconstruction is a competitive algorithm since it achieved a very satisfactory level of contrast enhancement and detail enhancement in dermoscopy images.

Comparison of SOX-10, HMB-45, and Melan-A in Benign Melanocytic Lesions.

PurposeDifferent immunohistochemical stains are used in dermatopathology to stain melanocytes and diagnose benign and malignant melanocytic lesions.MethodsSOX-10, HMB-45, and Melan-A immunohistochemical stains were used to assess 32 biopsy specimens with a histologic diagnosis of lentigo. The total number of melanocytes stained with each immunohistochemical stain was counted and an average count was obtained from two readings.ResultsAnalysis of the data revealed a significant difference in staining melanocytes between these three immunostains (p=0.0010, ANOVA). SOX-10 stained 0.195 more melanocytes than HMB-45 (p=0.0026). Similarly, Melan-A stained 0.195 more melanocytes than HMB-45 (p=0.0011). However, the difference between SOX-10 and Melan-A was not statistically significant (p=0.9810).ConclusionSOX-10 and Melan-A immunostaining stain more melanocytes than HMB-45. No significant difference was noted between Melan-A and SOX-10.