Towards Interpretable Skin Lesion Classification with Deep Learning Models.

Skin disease is a prevalent condition all over the world. Computer vision-based technology for automatic skin lesion classification holds great promise as an effective screening tool for early diagnosis. In this paper, we propose an accurate and interpretable deep learning pipeline to achieve such a goal. Comparing with existing research, we would like to highlight the following aspects of our model. 1) Rather than a single model, our approach ensembles a set of deep learning architectures to achieve better classification accuracy; 2) Generative adversarial network (GAN) is involved in the model training to promote data scale and diversity; 3) Local interpretable model-agnostic explanation (LIME) strategy is applied to extract evidence from the skin images to support the classification results. Our experimental results on real-world skin image corpus demonstrate the effectiveness and robustness of our method. The explainability of our model further enhances its applicability in real clinical practice.

A novel cumulative level difference mean based GLDM and modified ABCD features ranked using eigenvector centrality approach for four skin lesion types classification.

BACKGROUND AND OBJECTIVE: Melanoma is one of the major death causes while basal cell carcinoma (BCC) is the utmost incident skin lesion type. At their early stages, medical experts may be confused between both types with benign nevus and pigmented benign keratoses (BKL). This inspired the current study to develop an accurate automated, user-friendly skin lesion identification system. METHODS: The current work targets a novel discrimination technique of four pre-mentioned skin lesion classes. A novel proposed texture feature, named cumulative level-difference mean (CLDM) based on the gray-level difference method (GLDM) is extracted. The asymmetry, border irregularity, color variation and diameter are summed up as the ABCD rule feature vector is originally used to classify the melanoma from benign lesions. The proposed method improved the ABCD rule to also classify BCC and BKL by using the proposed modified-ABCD feature vector. In the modified set of ABCD features, each border feature, such as compact index, fractal dimension, and edge abruptness is considered a separate feature. Then, the composite feature vector having the pre-mentioned features is ranked using the Eigenvector Centrality (ECFS) feature ranking method. The ranked features are then classified by a cubic support vector machine for different numbers of selected features. RESULTS: The proposed CLDM texture features combined with the ranked ABCD features achieved outstanding performance to classify the four targeted classes (melanoma, BCC, nevi and BKL). The results report 100% outstanding performance of the sensitivity, accuracy and specificity per each class compared to other features when using the highest seven ranked features. CONCLUSIONS: The proposed system established that Melanoma, BCC, nevus and BKL are efficiently classified using cubic SVM with the new feature set. In addition, the comparative studies proved the superiority of the cubic SVM to classify the four classes.

"Pseudo-Circumscribed Palmar or Plantar Hypokeratosis (Pseudo-CPH)": a Histologic Pattern Secondary to Trauma; Further Characterization of a Known Entity.

Circumscribed palmar or plantar hypokeratosis (CPH) is defined clinically as well-circumscribed areas of erythematous eroded skin mostly over thenar or hypothenar eminences of the palms and less commonly soles. Histologically, lesions demonstrate a characteristic abrupt drop-off in the cornified layer leading to broad areas of hypokeratosis. In the original description in 2002, Perez et al favored these lesions to be a distinctive epidermal malformation. Since then, some reports implicate trauma; however, the exact etiology remains uncertain. The authors present 11 cases in which the histologic changes of CPH are present as an incidental finding that they favor to represent a reaction pattern to trauma. The changes of CPH overly traumatized neoplasms [ie, a poroma, squamous cell carcinoma (2), dermatofibroma], verruca vulgaris (3), inflammatory processes (lichen amyloid and granulomatous inflammation secondary to a ruptured infundibular cyst), and scar and fibrosing granulation tissue from previous procedures. Classic clinical findings of CPH are not present. The changes most commonly but not exclusively occur on acral skin (8/11), both volar (4) and dorsal skin (4). Six patients are female and 5 are male. Ages range from 21 to 87 years (median 64 years). The authors propose that, in some instances, the histologic changes of CPH are present as a secondary phenomenon and represent a reaction pattern to trauma. They name this finding of secondary histologic change of CPH as "pseudo-CPH" to distinguish it from primary lesions of CPH ("primary CPH") with classic clinical and histologic features.

Assessment, Definition, and Classification of Lower Limb Ulcers in Systemic Sclerosis: A Challenge for the Rheumatologist.

OBJECTIVE: To evaluate pathogenesis and clinical features of lower limb ulcers in systemic sclerosis (SSc) and to propose a classification that could be used in clinical practice. METHODS: Charts of 60 patients with SSc who had lower limb cutaneous lesions were reviewed. All patients had videocapillaroscopy and arterial and venous lower limb color Doppler ultrasonography (US). Arteriography was performed if occlusive peripheral arterial disease was suspected. RESULTS: The 554 lesions were classified as hyperkeratosis, ulcers, and gangrenes. There were 341 (61.6%) hyperkeratoses, 208 (37.5%) ulcers, and 5 (0.9%) gangrenes. Ulcers were divided into pure ulcers, ulcers associated with hyperkeratosis, and ulcers secondary to calcinosis. Involvement of arterial and venous macrocirculation as determined by color Doppler US was observed in 17 (18.3%) and 18 (30%) patients, respectively. Seventeen out of 37 patients with pure ulcers (45.9%) presented neither venous insufficiency nor hemodynamically significant macrovascular arterial disease. In these patients, pure ulcers were most likely caused by isolated SSc-related microvascular involvement (pure microvascular ulcers). The only significant risk factor for development of pure microvascular ulcers in the multivariate analysis was the history of lower limb ulcers (OR 26.67, 95% CI 2.75-259.28; p < 0.001). CONCLUSION: Results of our study indicate that lower limb ulcers in SSc often have a multifactorial pathogenesis that may be difficult to manage. Further studies are needed to validate the proposed classification and to assess the most appropriate management of lower limb ulcers in SSc.

¿Qué genodermatosis es? / Can You Identify the Genodermatosis?

No disponible

Multiple minute digitate hyperkeratoses: a case report.

Multiple minute digitate hyperkeratoses (MMDH) is a rare familial or acquired cutaneous eruption of filiform keratoses, typically across the trunk and extremities. Histopathology, distribution, and history can distinguish it from other digitate keratoses. We describe a case of MMDH and discuss it in relation to other disseminated digitate keratoses.

Frictional keratoses on the facial attached gingiva are rare clinical findings and do not belong to the category of leukoplakia.

PURPOSE: To investigate the clinical and histologic features of frictional keratoses located exclusively on the facial attached gingiva and establish whether these belong to the category of leukoplakia. MATERIALS AND METHODS: Over a period of 15 years, 159 patients presenting with oral keratotic plaques, located exclusively on the facial attached gingival mucosa, excluding the edentulous alveolar ridge and retromolar pad area, were retrospectively selected. Clinical and histologic features and the symptoms and progression of these lesions were carefully assessed. RESULTS: The presence of oral frictional keratosis located exclusively on the facial attached gingival mucosa was clinically and immunohistologically diagnosed in 14 of 159 patients (8.8%). Eleven patients (78.5%) showed unilateral involvement, whereas 3 patients (21.5%) had bilateral involvement. The disappearance of the lesions was accomplished in only 9 of 14 patients, resulting from discontinuation of bad habits. Clinically, these lesions appeared as distinct, sharply demarcated, isolated, asymptomatic, homogeneous whitish-plaques that were neither removable nor painful. The plaques did not create discomfort, change shape, or develop into malignancy. Histologically, these plaques showed features superimposable to those present in benign alveolar ridge keratoses. CONCLUSION: The results highlighted that frictional keratoses on the facial attached gingival mucosa 1) are rare findings, 2) clinically appear as "true leukoplakia" but histologically have the same features as benign alveolar ridge keratoses, 3) have no propensity for malignant transformation, 4) have a good prognosis, and 5) have a specific cause, and resolution is accomplished if the frictional element is eliminated. Thus, these must be removed from the category of leukoplakia.

Is acquired symmetrical acrokeratoderma a new dermatosis? Two case reports and Chinese literature review.

BACKGROUND: A series of cases characterized by symmetrical acral hyperkeratosis, mainly involving the dorsal surface of the hands, feet, and wrists, but sparing the palmoplantar areas, as well as rapid immersion upon exposure to water have been recently described in China, but similar disorders have not been reported in the English literature. METHODS: The clinicopathologic features of two cases of acquired symmetrical acrokeratoderma were reported and 27 Chinese patients were reviewed. RESULTS: The disorder typically occurred in young or middle aged men. Brown to black hyperkeratotic patches were symmetrically distributed particularly on the wrists and dorsum of hands, fingers, and feet, but without involvement of palms and soles. The lesions became whitish with mild swelling immediately after contact with water and improved generally in winter. Histopathologic examination revealed epidermal hyperkeratosis, acanthosis, and papillomatous hyperplasia, as well as superficial perivascular lymphohistiocytic infiltrate. Main ultrastructural features of the immersed lesion were epidermal hyperkeratosis and spongiosis with partial split of the desmosomes. CONCLUSION: This disorder may be a new dermatosis, and the term "acquired symmetrical acrokeratoderma" could exactly reflect its clinicopathologic characteristics.

Letter: It is Dermatosis neglecta.

The case presented in the article "Severe retention hyperkeratosis occurring with Susac syndrome" in October 2010 of DOJ (16:10) is very dramatic. Although it was implied in the article, the authors did not state that this is actually Dermatosis neglecta, the same entity reported by Poskitt et al 15 years ago. The description of the case in the article, histopathology, mechanism of pathogenesis, and treatment are consistent with Dermatosis neglecta, only with a different name.

Granular parakeratosis--a clinical-pathological correlation of 10 cases.

BACKGROUND: Granular parakeratosis describes chronic skin lesions within the intertriginous areas that demonstrate microscopically parakeratosis together with retention of keratohyalin granules within a thickened stratum corneum. Granular parakeratosis is rarely diagnosed, since it is still relatively unknown within the differential diagnoses of intertriginous eruptions, and a skin biopsy is required for diagnosis. In order to gain insight into the clinical-histopathologic correlation, we present 10 cases of granular parakeratosis. METHODS: The files of the DermatoHistologisches Labor Dr. H. Laaff, Freiburg, were searched for the diagnosis of granular parakeratosis. Identified cases were evaluated for clinical information and histopathologic characteristics. RESULT: From 2004 to 2007 10 cases (7 women, 3 men) of granular parakeratosis were found corresponding to a frequency of 0.004%. The average age was 62 (33-82). In women lesions occurred in submammary region (4), axillae (2) and popliteal fossa; in men, groin (2) and genital region. Clinically two different patterns are recognized--lichen planus-like red-brown slightly hyperkeratotic or scaly papules, and larger plaques which are either bright red shiny or grey-brown with lichenification. Histologically the typical granular parakeratosis was seen in a prominently thickened stratum corneum. It remains unclear whether granular parakeratosis is a disease entity or whether it reflects a reaction pattern to unknown stimuli.

Dermoscopy of lichen planus-like keratosis: a model of inflammatory regression.

BACKGROUND: Lichen planus-like keratosis (LPLK) or benign lichenoid keratosis is an involuting cutaneous entity where regressing features are the histologic hallmark. Most authors consider LPLK as an heterogeneous spectrum of intraepithelial epidermal or melanocytic lesions, mainly pigmented, involuting by inflammatory regression. OBJECTIVE: The authors review the clinico-histologic definition and correlate with the dermoscopic features of LPLK. METHODS: Sixteen LPLK were clinically distributed into three types: plaque-like (PL), flat erythematous (FE) and flat pigmented (FP) type and evaluated with conventional dermoscopy. Dermoscopic features of regression were recorded as the presence of blue-white structures and vascular structures. The predominant distribution, size and colour of pigmented granules were also recorded. All cases were excised and submitted to histopathologic examination and subdivided into three groups according to the early, classic and atrophic subtypes. RESULTS: The FP (44%) and the FE (37%) types are diagnosed more frequently than the PL type (19%). PL type correlates better with the classic type. FE correlates mainly with early/atrophic types, while the FP nearly exclusively with the late atrophic type. Regressive features are present in all but one case with a predominance of blue areas (94%). Localized (55%) and diffuse (37.5%) granular pattern are presenting in all but one case. The diffuse granular pattern correlates with the FP type (5/6 cases), while the localized granular pattern is mainly present (6/9 cases) in the FE type. Vascular structures can be found in half of the cases and white scar-like depigmentation is just present in four cases. BWS and vascular structures present together are observed in four cases (25%). CONCLUSIONS: Our results show a large correlation among clinical, histologic and dermoscopic aspects of LPLK may be interpreted as a spectrum of cutaneous lesions going into inflammatory regression, showing different clinical and dermoscopic patterns according to the involuting stage. The early type of LPLK (FE) shows a localized granular pattern where regression is at the very early stage. The classic dermoscopic features of regressing lesion for LPLK (pigmented granular pattern) apply to the most frequent encountered pigmented atrophic flat type or classic pigmented type, where sometimes regression is advanced or almost complete and no clear diagnosis of a previous benign/malignant - epithelial or melanocytic lesion can often be given. Regressive dermoscopic features must be evaluated in the context of global and clinical pattern of the lesion. Nonetheless dermoscopy can close correlate with clinical incipient or complete regression and must prompt the need for eventual prophylactic surgical removal.

Nomenclature and classification of potentially malignant disorders of the oral mucosa.

At a workshop coordinated by the WHO Collaborating Centre for Oral Cancer and Precancer in the UK issues related to terminology, definitions and classification of oral precancer were discussed by an expert group. The consensus views of the Working Group are presented here. The term, 'potentially malignant disorders', was recommended to refer to precancer as it conveys that not all disorders described under this term may transform into cancer. Critically evaluating all definitions proposed so far for oral leukoplakia, the Working Group agreed that the term leukoplakia should be used to recognize 'white plaques of questionable risk having excluded (other) known diseases or disorders that carry no increased risk for cancer'. An outline was proposed for diagnosing oral leukoplakia that will prevent other oral white disorders being misclassified as leukoplakia. The Working Group discussed the caveats involved in the current use of terminology and classification of oral potentially malignant disorders, deficiencies of these complex systems, and how they have evolved over the past several decades. The terminology presented in this report reflects our best understanding of multi-step carcinogenesis in the oral mucosa, and aspires to engender consistency in use.

Actinic keratosis is an early in situ squamous cell carcinoma: a proposal for reclassification.

The term actinic keratosis (AK) describes a sun-induced, clinical erythematous lesion covered with scale, but does not provide an understanding of the biology or histopathology of the lesion. Consequently, several classification systems for AK have been suggested, but as yet no consensus has been reached. These systems strive to correlate the pathological and clinical features to better provide physicians with the most accurate information to enable correct decisions to be made regarding treatments, Prognosis and metastatic potential. AK is a clinical description that has a histological diagnosis consistent with squamous cell carcinoma (SCC) in situ. We recommend an AK classification system that describes these lesions as squamous cell carcinomas (SCCs), using the terminology 'early in situ SCC Type AK I', 'early in situ SCC type AK II' and 'in situ SCC Type AK III', there by giving clinicians better guidance for diagnosis and specific treatment recommendations.

Bilateral comparison of the efficacy and tolerability of 3% diclofenac sodium gel and 5% 5-fluorouracil cream in the treatment of actinic keratoses of the face and scalp.

Actinic keratoses (AKs) are a common precancerous condition and are said to account for 14% of visits to dermatologists in the US each year. Along with cryotherapy, topical treatments are a mainstay of therapy for these lesions. One of the potential benefits of topical therapy is less pain and irritation as compared to cryotherapy. Additionally, topical therapies have a perceived benefit of treating subclinical lesions along with clinically evident keratoses. We conducted a bilateral comparison study of the efficacy and tolerability of diclofenac 3% gel used for 90 days and 5% fluorouracil cream used for 28 days in thirty patients with AK of the face and scalp. The diclofenac gel and 5-fluorouracil cream each demonstrated substantial efficacy in the number of lesions cleared and the proportion of patients with significant lesion clearing. In most patients, diclofenac induced only mild signs of inflammation compared to 5-fluoruracil, despite a longer treatment period. A greater number of patients expressed significant satisfaction with diclofenac gel compared to the 5-fluorouracil cream.

The diagnostic concordance of actinic keratosis and squamous cell carcinoma.

Diagnostic concordance of intraepithelial malignancy is generally only fair. Because the diagnosis of actinic keratosis (AK) and squamous cell carcinoma (SCC) is not uniform and because such terms are not consonant with the nomenclature of other human epithelial malignancies, nomenclature revisions have been attempted. One hundred dermatopathologists were solicited to review 15 tissue sections representing a spectrum of varying thickness epidermal malignancy and to choose either AK or SCC as the diagnosis. Among the 77 participating dermatopathologists, intraclass correlation was high for what was perceived as AK, SCC, and their differentiation. Development of a two-tiered diagnostic system that retains our present diagnostic capabilities, but better fits the pathobiology of superficial epidermal malignancy is suggested. Davis DA, Donahue JP, Bost JE, Horn TD. The diagnostic concordance of actinic keratosis and squamous cell carcinoma.

Erythrokeratodermas: a classification in a state of flux?

The term 'erythrokeratodermas' or 'erythrokeratodermias' has been applied to a group of inherited disorders characterized by well-demarcated erythematous lesions and hyperkeratotic plaques. Connexin mutations have been demonstrated to be responsible for most cases of erythrokeratoderma variabilis but there remain some cases without demonstrated connexin mutations, suggesting genetic heterogeneity. The position of progressive symmetric erythrokeratoderma has become rather unclear. Loricin mutations have been found in some cases that clinically resemble variant Vohwinkel syndrome and other cases have features that overlap with those of erythrokeratoderma variablis. Whether progressive symmetric erythrokeratoderma exists as a distinct entity is under question.

New histopathological classification of actinic keratosis (incipient intraepidermal squamous cell carcinoma).

Actinic keratoses are common, sun-induced lesions that have historically been regarded as "premalignant." Evidence supports their inclusion along a continuum with squamous cell carcinoma. We propose a classification analogous to that used for cervical intraepithelial neoplasia.

[Circumscribed acral hypokeratosis]. / Zirkumskripte akrale Hypokeratose.

Circumscribed acral hypokeratosis is a rare chronic disorder of cornification that occurs predominantly in women. Lesions are solitary and do not respond to any local conservative treatment. They have to be differentiated by biopsy from other non-healing lesions and tumors in acral skin. Clinically lesions appear as sharply circumscribed reddish macules. The histologic hallmark is a circumscribed loss of the entire stratum corneum, which can be best demonstrated at the border of the lesion as a contrast to the perilesional broad stratum corneum typical for acral sites.