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H F Lorentzen

Publications and source records attributed to H F Lorentzen.

8 recordsLinked to original sources
PubMed2001

Structural asymmetry as a dermatoscopic indicator of malignant melanoma--a latent class analysis of sensitivity and classification errors.

Asymmetry of pigmented skin lesions is an important indicator of possible malignant melanoma and contributes substantially to the diagnosis of melanoma in the dermatoscopic ABCD rule for melanocytic lesions and other algorithms. However, it may be observer dependent. Dermatoscopic asymmetry cannot be assessed objectively and no golden standard of asymmetry diagnosis exists. The aim of this study was to assess the sensitivity of axis (a-) symmetry using latent class analysis. We analysed ratings from four experts in dermatoscopy of 232 pigmented lesions by latent class analysis (LCA). Possible ratings were 'no asymmetry', 'asymmetry in one axis' and 'asymmetry in two axes'. A subset of melanocytic lesions (blue naevi excluded) was analysed. Based on LCA, the asymmetry of the singular lesion was determined. The sensitivity of 'no asymmetry' was 40-77%, 40-70% for one-axis asymmetry, and 77-92% for two-axes asymmetry. Overestimation of asymmetry was more common than underestimation. Melanomas were significantly more asymmetric than pigmented naevi, atypical naevi and papillomas, but not basal cell cancers. Analysis of the melanocytic subset gave similar results. The median asymmetry of malignant melanomas (1.67, interquartile range 1.81-1.99) was higher than for melanocytic naevi. In conclusion, asymmetry and symmetry are important criteria for diagnosing or excluding malignant melanoma using the dermatoscopic ABCD rule, risk stratification and other diagnostic rules. Using LCA, we minimized observer dependence in the assessment of axis (a-) symmetry. LCA, besides conceptualizing the diagnostic process, enables the assignment of lesions to their true diagnostic class.

Basal Cell Carcinoma↗
PubMed2000

[Zinc deficiency and pellagra in alcohol abuse].

We report two cases of nutritional deficiency with skin symptoms associated with excessive intake of wine and beer, causing respectively pellagra and zinc deficiency. Supplementation with niacin and zinc had a prompt effect on the skin changes. These cases emphasize the importance of keeping nutritional deficiencies in mind in patients with inadequate nutrition and alcohol abuse.

Adult↗
PubMed2000

[Sunbathing habits and risk of melanoma].

The increasing frequency of malignant melanoma (MM) is believed mainly to be due to the habit of sunbathing, which has an impact on the skin due to ultraviolet radiation, especially if intermittent and causing sunburn. Frequent use of tanning booths possibly increases the risk of MM but the question has not been settled. Use of sunscreens has a certain prophylactic effect on actinic keratoses, but no documented effect on MM. This does not imply that sunscreens are not advisable, but stresses the importance of correct use of sunscreens together with other sun protective measures. Primary prevention of MM is mainly a question of minimizing the impact of ultraviolet radiation (including tanning booths) on the skin: limit time in the sun, cover up with clothing, and use a sunscreen with a protection factor of at least 15.

Humans↗
PubMed2000

[Dermatoscopic diagnosis of cutaneous malignant melanoma. Secondary prophylaxis].

During the last four decades the incidence of malignant melanoma has increased seven fold. Clinically, it is often difficult to distinguish malignant melanoma from a benign naevus. The macroscopic clinical ABCD rule and the Glasgow 7-point checklist are didactically helpful, but inaccurate with many false positive and negative diagnoses. Dermatoscopy performed by a trained physician has increased the diagnostic accuracy to a sensitivity of 89% and specificity of 80% (meta-analysis of 11 studies). The dermatoscopic ABCD rule and the Risk Stratification method (RS) are reviewed.

Diagnosis, Differential↗
PubMed1999

[Interobserver variation in the Red-Yellow-Black wound classification system].

Communicating wound descriptions between disciplines for treatment and wound care necessitates a simple and unequivocal classification system. The Red-Yellow-Black (RYB) system has been suggested to comply with these demands. The reliability of the RYB-system has, however only been investigated in small studies. The aim of this study was to determine interobserver homogeneity (group Kappa a.m. Schouten) of the RYB-system and further to examine whether interobserver homogeneity was dependent on educational level. One-hundred-and-twenty photo-slides of non-healing ulcers of various etiologies were shown to 21 observers who recorded their assessments in an entry form without discussing their assessments with the other observers. Eighty-nine percent of the possible assessments were completed. Observed agreement for all observers = 0.65; Kappa = 0.47. Kappa-coefficient in subgroup of nurses = 0.49, subgroup of physicians with less than three years of experience with wound treatment = 0.46 and for physicians with more than 10 years of experience with wound healing = 0.48. In conclusion, we demonstrated moderate interobserver agreement for using the RYB-characteristics. The RYB-system is useful for communication about wound care and treatment. However, continuous education and consensus meetings are advisable to increase agreement.

Humans↗
PubMed1998

[Interobserver variation in wound assessments].

Agreement in describing a chronic leg ulcer is pivotal in identifying and treating impediments to the healing process. Six nurses and one doctor without special experience with wound healing registered wound related diagnoses for a five month period. On average each patient was seen by three observers yielding 270 registrations. Agreement beyond chance (global kappa) showed poor to moderate agreement. Agreement was best for the yellow or malodorous wound and lowest for cellulitis, hypergranulation and peripheral pulses. This emphasizes the importance of allocating wound treatment to specialist departments with access to paraclinical investigations.

Clinical Competence↗
PubMedDate not supplied

Dermatoscopic prediction of melanoma thickness using latent trait analysis and likelihood ratios.

Breslow thickness and Clark level can be used to determine surgical procedures for cutaneous malignant melanoma and patient eligibility for experimental adjuvant therapy. Efforts to predict the thickness of melanomas using dermatoscopy have focused on differences between single dermatoscopic findings. The aim of this study was to develop a method for preoperative identification of melanomas of > or = 1 mm Breslow thickness using the entire range of dermatoscopic findings. Sixty-five melanomas were assessed for the presence of 22 dermatoscopic features. Ten dermatoscopic features showed differences in thick and thin melanomas and were selected for further analysis. A latent trait analysis construct implied that a progression in dermatoscopic features was associated with advancement of melanomas. Early melanomas are characterized by a light brown colour, a pigment network and irregularity or heterogeneity. Gray-blue areas, white scar-like areas and an atypical vascular pattern gradually displace these features. Likelihood ratios were determined for these 6 dermatoscopic findings and an algorithm for calculating the probability of thick malignant melanoma was established.

Denmark↗