Diagnostic performance of a deep learning convolutional neural network in the differentiation of combined naevi and melanomas.

BACKGROUND: Deep learning convolutional neural networks (CNN) may assist physicians in the diagnosis of melanoma. The capacity of a CNN to differentiate melanomas from combined naevi, the latter representing well-known melanoma simulators, has not been investigated. OBJECTIVE: To assess the diagnostic performance of a CNN when used to differentiate melanomas from combined naevi in comparison with dermatologists. METHODS: In this study, a CNN with regulatory approval for the European market (Moleanalyzer-Pro, FotoFinder Systems GmbH, Bad Birnbach, Germany) was used. We attained a dichotomous classification (benign, malignant) in dermoscopic images of 36 combined naevi and 36 melanomas with a mean Breslow thickness of 1.3 mm. Primary outcome measures were the CNN's sensitivity, specificity and the diagnostic odds ratio (DOR) in comparison with 11 dermatologists with different levels of experience. RESULTS: The CNN revealed a sensitivity, specificity and DOR of 97.1% (95% CI [82.7-99.6]), 78.8% (95% CI [62.8-89.1.3]) and 34 (95% CI [4.8-239]), respectively. Dermatologists showed a lower mean sensitivity, specificity and DOR of 90.6% (95% CI [84.1-94.7]; P = 0.092), 71.0% (95% CI [62.6-78.1]; P = 0.256) and 24 (95% CI [11.6-48.4]; P = 0.1114). Under the assumption that dermatologists use the CNN to verify their (initial) melanoma diagnosis, dermatologists achieve an increased specificity of 90.3% (95% CI [79.8-95.6]) at an almost unchanged sensitivity. The largest benefit was observed in 'beginners', who performed worst without CNN verification (DOR = 12) but best with CNN verification (DOR = 98). CONCLUSION: The tested CNN more accurately classified combined naevi and melanomas in comparison with trained dermatologists. Their diagnostic performance could be improved if the CNN was used to confirm/overrule an initial melanoma diagnosis. Application of a CNN may therefore be of benefit to clinicians.

[New optical examination procedures for the diagnosis of skin diseases]. / Neue optische Untersuchungsverfahren für die Diagnostik von Hautkrankheiten.

BACKGROUND: Since the establishment of dermoscopy as a routine examination procedure in dermatology, the spectrum of noninvasive, optical devices has further expanded. In difficult-to-diagnose clinical cases, these systems may support dermatologists to arrive at a correct diagnosis without the need for a surgical biopsy. OBJECTIVE: To give an overview about technical background, indications and diagnostic performance regarding four new optical procedures: reflectance confocal microscopy, in vivo multiphoton tomography, dermatofluoroscopy, and systems based on image analysis by artificial intelligence (AI). MATERIALS AND METHODS: This article is based on a selective review of the literature, as well as the authors' personal experience from clinical studies relevant for market approval of the devices. RESULTS: In contrast to standard histopathological slides with vertical cross sections, reflectance confocal microscopy and in vivo multiphoton tomography allow for "optical biopsies" with horizontal cross sections. Dermatofluoroscopy and AI-based image analyzers provide a numerical score, which helps to correctly classify a skin lesion. The presented new optical procedures may be applied for the diagnosis of skin cancer as well as inflammatory skin diseases. CONCLUSION: The presented optical procedures provide valuable additional information that supports dermatologists in making the correct diagnosis. However, a surgical biopsy followed by dermatohistopathological examination remains the diagnostic gold standard in dermatology.

PD-1 blockade: a therapeutic option for treatment of metastatic Merkel cell carcinoma.

The immune system is extremely important in the development and progression of Merkel cell carcinoma (MCC). Immune checkpoint blockade has recently been shown to enable efficacious treatment of a variety of tumours. We report the use of an anti-programmed death receptor 1 (PD-1) antibody for treatment of a patient with metastatic MCC. An 80-year-old patient with metastatic MCC received off-label treatment with the anti-PD-1 antibody pembrolizumab after the disease had progressed during therapy with oral etoposide. A positron emission tomography (PET) computed tomography scan performed after three cycles of pembrolizumab revealed responses to therapy with reduced size of the adrenal gland metastases and less PET activity in the adrenal gland and lymph node metastases. Treatment was resumed owing to disease progression after a treatment-free interval of > 4 months. During subsequent months of treatment, the size of the metastases stabilized and uptake of nuclide by all tumour sites once again decreased. These results reveal the potential efficacy of an anti-PD-1 antibody for treatment of metastatic MCC. Thus, they contribute to currently limited data on the use of anti-PD-1 antibodies for the treatment of MCC. Moreover, this is the first report of successful resumption of treatment of metastatic MCC with an anti-PD-1 antibody. Results from ongoing trials will contribute to determination of the relevance of PD-1 blockade in metastatic MCC.

[Malignant melanoma : Current status]. / Malignes Melanom : Aktueller Stand.

CLINICAL ISSUE: The incidence of malignant melanoma is continuously increasing. The prognosis of metastatic disease is still limited. STANDARD TREATMENT: Until a few years ago palliative chemotherapy with a limited response rate was the standard treatment for metastatic melanoma. TREATMENT INNOVATIONS: Immunotherapy and targeted therapy provide new treatment options. Immune checkpoint inhibitors have significantly improved the prognosis. DIAGNOSTIC WORK-UP: Regional lymph node sonography, computed tomography (CT) of the neck, chest and abdomen and brain magnetic resonance imaging (MRI) are routinely used. As an alternative to CT scans 18 F fluorodeoxyglucose positron emission tomography (FDG-PET) may be used. PERFORMANCE AND ACHIEVEMENTS: Immunotherapy provides the chance of long-term disease control in metastatic melanoma. Ipilimumab may provide long-term tumor control in approximately 20% of patients. Median overall survival of approximately 2 years is achieved during therapy with anti-programmed cell death (PD) 1 antibodies. For combined therapy of ipilimumab and nivolumab a response rate of almost 60% is achieved and 2­year survival is also approximately 60%. The range of immune-mediated side effects demands particular consideration. For response evaluation immune-related response criteria were defined. Furthermore, immunotherapeutic approaches, such as talimogene laherparepvec (T-VEC), which is a modified herpes virus can be used for intralesional injection. PRACTICAL RECOMMENDATIONS: An individual definition of the appropriate therapy for each patient is of particular importance. In the context of modern therapy regimens close patient monitoring is crucial.

[Multiple eccrine hidrocystomas on the lower forehead and nose of a 60-year-old man]. / Multiple ekkrine Hidrozystome an Stirn und Nase eines 60-jährigen Mannes.

Multiple eccrine hidrocystomas are benign cystic skin lesions which originate from the sweat gland ducts and typically affect women's midfacial area. Sweating may lead to an increase in size of the translucent papules. In some cases hidrocystomas are associated with other diseases such as Parkinson's disease. Treatment options include laser, topical and systemic anticholinergic drugs (glycopyrrolate, clonidine, atropine, and oxybutynin), whereby therapeutic success is limited in most cases.

Analysis of UMP synthase gene and mRNA structure in hereditary orotic aciduria fibroblasts.

Hereditary orotic aciduria is an autosomal recessive disease in which there is a severe deficiency in the activity of the de novo pyrimidine pathway enzyme uridine 5'-monophosphate (UMP) synthase. UMP synthase is a bifunctional enzyme containing the two activities orotate phosphoribosyltransferase and orotidine 5'-monophosphate decarboxylase, which catalyze the two-step conversion of orotic acid to UMP. Cell lines from three orotic aciduria patients have been characterized for UMP synthase gene and mRNA content. Restriction-enzyme analysis of DNA from the deficient cells revealed no changes in the gene structure compared with normal cell DNA structure. The amount of UMP synthase mRNA was not decreased, nor was there a detectable difference in the size of the UMP synthase mRNA in the deficient cells. Analysis of the mRNA by hybridization with a nearly full-length UMP synthase cDNA followed by S1 nuclease digestion showed no alteration in the mRNA structure. The UMP synthase activity of the deficient cells ranges from 2% to 7% of the normal cell level. The activity can be significantly increased by growing the deficient cells in barbituric acid. Our data indicate that UMP synthase gene transcription in the orotic aciduria cells produces the expected amount of a stable, correctly processed mRNA. The mRNA appears to code for a mutant enzyme that has reduced stability or altered kinetic properties.

Molecular cloning and nucleotide sequence for the complete coding region of human UMP synthase.

The last two steps in the de novo biosynthesis of UMP are catalyzed by orotate phosphoribosyltransferase (OPRT; orotidine-5'-phosphate:pyrophosphate phosphoribosyltransferase; EC 2.4.2.10) and orotidine-5'-monophosphate decarboxylase (orotidine-5'-phosphate carboxy-lyase; EC 4.1.1.23). In mammals these two activities are found in a single, bifunctional protein called UMP synthase. A human T-lymphoblastic cell cDNA library constructed in lambda gt10 was screened with a UMP synthase-specific rat cDNA probe. Human UMP synthase cDNAs were isolated and then used to select UMP synthase gene fragments. The complete coding sequence of the mRNA for UMP synthase was determined by analysis of overlapping cDNA and genomic fragments. One of the cDNAs appears to have been synthesized from an incompletely or alternatively processed form of the UMP synthase mRNA. This cDNA lacks a poly(A) tail and has an extended 3'-nontranslated region that hybridizes with larger forms of the UMP synthase mRNA. The UMP synthase protein is composed of 480 amino acids with a molecular weight of 52,199. The two activities of UMP synthase reside in distinct domains encoded by the 3' and 5' halves of the mRNA. The COOH-terminal 258 amino acids of the human UMP synthase protein contain the orotidine-5'-monophosphate decarboxylase catalytic domain. This region is highly homologous to the mouse orotidine-5'-monophosphate decarboxylase sequence. The NH2-terminal 214 amino acids contain the OPRT domain. There is amino acid homology between this protein domain and specific regions of the Escherichia coli OPRT. The human OPRT domain also contains the putative catalytic site common to other human phosphoribosyltransferases.

Altered regulation of protein disulfide isomerase in cells resistant to the growth-inhibitory effects of transforming growth factor beta 1.

A murine keratinocyte cell line that is resistant to the growth-inhibitory effects of transforming growth factor beta 1 (TGF beta 1) was examined for differential gene expression patterns that may be related to the mechanism of the loss of TGF beta 1 responsiveness. Cells that were resistant to the growth-inhibitory effects of TGF beta 1 (KCR cells) were derived from K-ras-transformed BALB/MK keratinocytes (KC cells). Using a subtractive hybridization procedure with KC and KCR mRNAs, we isolated a complementary DNA clone for murine protein disulfide isomerase (PDI). The mRNA for PDI is inhibited by TGF beta 1 treatment in the parental KC cells, but not in the TGF beta 1-resistant KCR cells. Similar PDI down-regulation also occurs in other TGF beta-sensitive cells, but not in a human pancreatic carcinoma cell line which is insensitive to the growth-inhibitory effects of TGF beta 1. The results suggest that misregulation of PDI, an important component of co- and posttranslational modification systems, may be involved in the mechanism by which some cells escape from the growth-inhibitory effects of TGF beta 1.