Dermatoscopy of combined blue nevi: a multicentre study of the International Dermoscopy Society.

BACKGROUND: Combined blue nevi (CBN) may mimic melanoma and are relatively often biopsied for diagnostic reasons. OBJECTIVE: To better characterize CBN and to compare it with melanoma. METHODS: We collected clinical and dermatoscopic images of 111 histologically confirmed CBN and contrasted their dermatoscopic characteristics with 132 partly blue coloured melanomas. Furthermore, we compared the accuracy of human experts using pattern analysis with a computer algorithm based on deep learning. RESULTS: Combined blue nevi are usually flat or slightly elevated and, in comparison with melanoma, more frequent on the head and neck. Dermatoscopically, they are typified by a blue structureless part in combination with either brown clods (n = 52, 46.8%), lines (n = 28, 25.2%) or skin-coloured or brown structureless areas (n = 31, 27.9%). In contrast with melanoma, the blue part of CBN is more often well defined (18.9% vs. 4.5%, P < 0.001) and more often located in the centre (22.5% vs. 5.3%, P < 0.001). Melanomas are more often chaotic (OR: 28.7, 95% CI: 14.8-55.7, P < 0.001), have at least one melanoma clue (OR: 10.8, 95% CI: 5.2-22.2 P < 0.001) in particular white lines (OR: 37.1, 95% CI: 13.4-102.9, P < 0.001). Using simplified pattern analysis (chaos and clues), two raters reached sensitivities of 93.9% (95% CI: 88.4-97.3%) and 92.4% (95% CI: 86.5-96.3%) at corresponding specificities of 59.5% (95% CI: 49.7-68.7%) and 65.8% (95% CI: 56.2-74.5%). The human accuracy with pattern analysis was on par with a state-of-the-art computer algorithm based on deep learning that achieved an area under the curve of (0.92, 95% CI: 0.87-0.96) and a specificity of 85.3% (95% CI: 76.5-91.7%) at a given sensitivity of 83.6% (95% CI: 72.5-91.5%). CONCLUSION: CBN usually lack melanoma clues, in particular white lines. The accuracy of pattern analysis for combined nevi is acceptable, and histopathologic confirmation may not be necessary in exemplary cases.

Dermatoscopic features of thin (≤2 mm Breslow thickness) vs. thick (>2 mm Breslow thickness) nodular melanoma and predictors of nodular melanoma versus nodular non-melanoma tumours: a multicentric collaborative study by the International Dermoscopy Society.

BACKGROUND: Thin nodular melanoma (NM) often lacks conspicuous melanoma-specific dermatoscopic criteria and escapes clinical detection until it progresses to a thicker and more advanced tumour. OBJECTIVE: To investigate the dermatoscopic morphology of thin (≤2 mm Breslow thickness) vs. thick (>2 mm) NM and to identify dermatoscopic predictors of its differential diagnosis from other nodular tumours. METHODS: Retrospective, morphological case-control study, conducted on behalf of the International Dermoscopy Society. Dermatoscopic images of NM and other nodular tumours from 19 skin cancer centres worldwide were collected and analysed. RESULTS: Overall, 254 tumours were collected (69 NM of Breslow thickness ≤2 mm, 96 NM >2 mm and 89 non-melanoma nodular lesions). Light brown coloration (50.7%) and irregular brown dots/globules (42.0%) were most frequently observed in ≤2 mm NMs. Multivariate analysis revealed that dotted vessels (3.4-fold), white shiny streaks (2.9-fold) and irregular blue structureless area (2.4-fold) were predictors for thinner NM compared to non-melanoma nodular tumours. Overall, irregular blue structureless area (3.4-fold), dotted vessels (4.6-fold) and serpentine vessels (1.9-fold) were predictors of all NM compared to non-melanoma nodular lesions. LIMITATIONS: Absence of a centralized, consensus pathology review and cases selected form tertiary centres maybe not reflecting the broader community. CONCLUSIONS: Our study sheds light into the dermatoscopic morphology of thin NM in comparison to thicker NM and could provide useful clues for its differential diagnosis from other non-melanoma nodular tumours.

Clinical response correlates with 4-week postinjection ustekinumab concentrations in patients with moderate-to-severe psoriasis.

BACKGROUND: Cost-effective use of biologicals is important. As drug concentrations have been linked to clinical outcomes, monitoring drug concentrations is a valuable tool to guide clinical decision-making. A concentration-response relationship for ustekinumab at trough is uncertain owing to the contradictory results reported. OBJECTIVES: To investigate the relationship between 4-week postinjection ustekinumab concentrations and clinical response in patients with psoriasis. METHODS: Forty-nine patients with moderate-to-severe psoriasis treated with 45 mg or 90 mg ustekinumab every 12 weeks for ≥ 16 weeks were included. Ustekinumab serum concentrations and anti-ustekinumab antibodies were measured at week 4 after injection and disease severity was assessed by Psoriasis Area and Severity Index (PASI). RESULTS: At week 4 after injection, a significantly negative correlation was observed between ustekinumab concentrations and absolute PASI score up to 5·9 µg mL-1 (ρ = -0·357, P = 0·032). Ustekinumab concentrations were higher in optimal responders (PASI ≤ 2) than in suboptimal responders (PASI > 2) (4·0 vs 2·8 µg mL-1 , P = 0·036). The ustekinumab concentration threshold associated with optimal response was determined to be 3·6 µg mL-1 (area under the curve 0·71, sensitivity 86%, specificity 63%). Only one patient (2%) had anti-ustekinumab antibodies. Psoriatic arthritis was identified as an independent predictor of higher PASI scores and higher ustekinumab concentrations (P = 0·003 and P = 0·048, respectively). CONCLUSIONS: A concentration-response relationship at week 4 after injection was observed for patients with psoriasis treated with ustekinumab. Monitoring 4-week postinjection ustekinumab concentrations could timely identify underexposed patients who might benefit from treatment optimization. What's already known about this topic? Monitoring drug concentrations is a valuable tool that can guide clinical decision-making when drug concentrations are linked to clinical outcomes. The presence of a concentration-response relationship for ustekinumab at trough is still debated owing to the contradictory results reported. What does this study add? A concentration-response relationship at week 4 after injection for ustekinumab-treated patients with psoriasis was demonstrated. Monitoring 4-week postinjection ustekinumab concentrations could timely identify underexposed patients who might benefit from treatment optimization. Based on the findings of this study, a treatment algorithm for patients with a suboptimal response is proposed.

Dermoscopic features of mammary Paget's disease: a retrospective case-control study by the International Dermoscopy Society.

BACKGROUND: Mammary Paget's disease (MPD) is a rare intraepidermal adenocarcinoma of the nipple-areola complex, associated with an underlying breast cancer in approximately 90% of cases. Delayed diagnosis of MPD is common. Its dermoscopic features have been ill defined in the literature. OBJECTIVES: To determine the clinical and dermoscopic features of MPD versus other dermatologic entities that involve nipple and areola. METHODS: Members of the IDS were invited to submit any case of histologically confirmed MPD, as well as other benign and malignant dermatoses that involve the nipple and areola complex. A standardized evaluation of the dermoscopic images was performed and the results were statistically analyzed. RESULTS: Sixty-five lesions were included in the study, 22 (33.8%) of them MPD and 43 (66.2%) controls. The most frequent dermoscopic criteria of MPD were white scales (86.4%) and pink structureless areas (81.8%), followed by dotted vessels (72.7%), erosion/ulceration (68.2%) and white shiny lines (63.6%). The multivariate analysis showed that white scales and pink structureless areas were significant predictors of MPD, posing a 68-fold and a 31-fold probability of MPD, respectively. Split of the population into pigmented and non-pigmented lesions showed that in pigmented MPD, pink structureless areas, white lines and grey granules and dots are positive predictors of the disease. Among non-pigmented lesions, pink structureless areas, white lines, erosion/ulceration and white scales served as predictors of MPD. CONCLUSIONS: The most frequent profile of an individual with MPD is an elderly female with unilateral, asymptomatic, erythematous plaque of the nipple, dermoscopically displaying pink structureless areas, fine white scales, dotted and a few short linear vessels. In case of pigmentation we may also observe brown structureless areas and pigmented granules. LIMITATIONS: Small sample size, retrospective design.

Rosettes and other white shiny structures in polarized dermoscopy: histological correlate and optical explanation.

BACKGROUND: Rosettes are a specific form of a white shiny structure seen with polarized dermoscopy. The precise morphological correlate and optical explication are not known. OBJECTIVE: To estimate the frequency of rosettes in ex vivo dermoscopy and to find explication and morphologic correlate of this dermoscopic feature. METHODS: A series of 6108 consecutive skin biopsies were examined with ex vivo dermoscopy and when rosettes were present serial transverse sections with polarization were examined. RESULTS: In this series of 6108 consecutive skin biopsies, rosettes were found on ex vivo dermoscopy in 63 cases. When multiple we observed that they are always oriented at the same angle. Transverse sections with polarization of these lesions proved that smaller rosettes are mainly caused by polarizing horny material in adnexal openings, and larger rosettes by concentric perifollicular fibrosis. CONCLUSIONS: Rosettes are an optical effect of crossed polarization by concentric fibrosis or horny material and hence are not lesion-specific.

Dermatologic lesions and risk for cancer.

There are three major types of skin cancer. Basal cell carcinoma and squamous cell carcinoma are both carcinomas from epithelial cells, whereas melanoma originates from the melanocytes of the skin. Although these skin cancers can develop without precursors, there are some skin lesions which may give rise to malignancies. In chronological order, we discuss the (potential) precancerous lesions of basal cell carcinoma (sebaceous nevus), squamous cell carcinoma (chronic inflammation, actinic keratosis, kerato-acanthoma, Bowen's disease, leukoplakia, and lichen sclerosus) and malignant melanoma (lentigo maligna and dysplastic naevi).