Biomedical subjects
Publications and source records attributed to C C Harland.
We report a case of an immunocompromised 38-year-old Asian patient who developed several hundred atypical lesions of molluscum on her face and neck, resistant to conventional treatment. These lesions were treated successfully by potassium titanyl phosphate (KTP) laser without pigmentary disturbance. KTP laser is a novel treatment for molluscum contagiosum.
BACKGROUND/AIMS: High-resolution ultrasound (HRU) is a relatively cheap imaging method that shows small quantitative differences between benign naevi and melanoma. Previous studies using B-mode display suggest that these arise from their differing attenuating properties. Attenuation characteristics, however, are better evaluated using reflex transmission imaging (RTI). White light clinical (WLC) photography is an even cheaper imaging method that is routinely used for monitoring but less frequently in everyday diagnosis. As features from each method may have an independent origin, two such modalities may be of greater diagnostic value than either method alone. However, although quantitative analysis of digital photographs is being developed to aid tumour diagnosis, in vivo RTI for the evaluation of pigmented skin lesions has not previously been described. This paper presents the feasibility of performing RTI in vivo and evaluates the reliability of the objective features used. The potential of the combination of quantitative RTI and white light (WL) digital photography data for the classification of pigmented lesions was assessed. METHODS: Randomly selected patients were recruited via a skin cancer screening clinic. RTI data were acquired from each index lesion with a 20 MHz single-element scanner. WL images were taken using a high-resolution (2.8 Mpixels) digital camera. Quantitative features calculated from both images were used to derive a discriminant rule. This equation was then applied to reclassify each case based on its quantitative criteria. The resultant classification was compared with histological diagnosis. RESULTS: Twenty-four lesions (10 melanoma and 14 naevi) were studied. On RTI, no subjective differences were observed between benign naevi and melanoma. Many lesions were either not visible on RTI or lacked clearly definable borders. Consequently, the WL photographs were used to draw lesion boundaries on RT images for feature calculation. Melanoma were less attenuating than naevi on RTI (P=0.026) and had greater red colour variegation on WL imaging (P=0.016). The combination of quantitative parameters (two from RTI and four from photographs) improved sensitivity for this sample without compromising the specificity of 100% compared with either modality alone. The procedure is highly reproducible (r=0.85 between two operators). CONCLUSIONS: Pigmented skin lesions can be quantitatively defined from RTI data acquired in vivo and a significant difference in attenuation is shown. However, accurate registration of the RT image with a corresponding photograph was crucial for this purpose and only possible when corresponding points could be reliably identified on both images. Combination of features from ultrasound and optical images may synergistically improve diagnostic accuracy and a larger study is warranted to investigate this.
BACKGROUND: Blood flow is substantially raised in psoriatic plaques. In addition, mechanisms of vasoconstriction and vasodilatation (locally and neurally mediated), although intact, are altered in magnitude. The elevated blood flow is considered to be a result of abnormalities (increase in vessel number, width and length) in the superficial capillary loops rather than changes in the deeper feeding vessels (arterioles). OBJECTIVES: To determine if selective thermolysis of psoriatic capillaries with a pulsed dye laser (PDL) leads to normalization of blood flow and also if the vasoconstrictor and vasodilator responses are returned to normal magnitude. METHODS: Laser Doppler red cell flux was recorded from plaques on the forearm or elbow (untreated plaque site) and from clinically uninvolved skin at an equivalent site on the opposite limb. Plaques were treated on three occasions, at 2-weekly intervals, with a PDL. Laser Doppler red cell flux measurements were then repeated, 2 weeks after the final laser treatment was performed (treated plaque site). RESULTS: There was significant clinical improvement in plaques after treatment (P = 0.02), but complete clearance of lesions did not occur. Blood flow in plaques under basal conditions remained significantly elevated above blood flow in clinically uninvolved skin, despite laser treatment (P < 0.001). The physiological tests of resistance vessel function showed that the laser did not impair the ability of psoriatic resistance vessels to constrict and dilate. However, there was only partial resolution of the percentage responses to the provocation tests towards the values recorded in clinically uninvolved skin. CONCLUSIONS: The results indicate that it is unlikely that the reduced resistance of the expanded superficial capillary bed is solely responsible for the massively elevated blood flow in plaque skin. It is more likely that the vascular abnormalities in psoriasis also extend to involve the deeper, larger resistance vessels (arterioles).
BACKGROUND: Microvascular abnormalities (capillary elongation, widening and tortuosity) are a characteristic feature of psoriasis and form one of the pathological diagnostic criteria. These changes occur early in the progression of a psoriatic plaque, before there is clinical or histological evidence of epidermal hyperplasia. Treatment of psoriatic microvessels with a pulsed dye laser (PDL) has been associated with both clinical improvement and clearance of lesions. OBJECTIVES: To quantify the structural vascular abnormalities in plaque skin using noninvasive techniques in vivo. Investigations were carried out before and after PDL treatment to determine the nature of laser-induced microvascular changes and the relationship between these changes and clinical improvement. METHODS: Plaque microvessels were visualized using native capillaroscopy. Plaques were then treated three times with the PDL at 14-day intervals. Native capillaroscopy was repeated at 2 and 6 weeks after the final laser treatment. Images were analysed using a combination of nonstereological and stereological measurements. RESULTS: Whole body disease was stable. Treated plaques showed a 48% reduction in plaque severity score (P < 0.01). Native studies showed that the PDL significantly reduced plaque microvessel density (P < 0.05), image area fraction (P < 0.01), microvessel length density (P < 0.01) and vessel image width (P < 0.01). The reduction in plaque severity score (which denoted clinical improvement) was related quantitatively to the reduction in microvessel area per unit area of plaque skin, i.e. the image area fraction (correlation coefficient = 0.772, P < 0.01). The greatest response of plaque microvessels was within 2 weeks after the final laser treatment, while the greatest reduction in plaque severity score occurred between 2 and 6 weeks after the final laser treatment, i.e. clinical improvement was preceded by microvascular improvement. CONCLUSIONS: These findings indicate that there is a close correlation between the state of the superficial vasculature and the clinical status of psoriasis. The expanded superficial microvascular bed in plaque skin is a necessary component for maintaining clinical lesions and these blood vessels are thus a legitimate target for treatment.
Brooke-Spiegler syndrome is a rare genetic condition associated with adnexal and epidermal tumours. Facial trichoepitheliomas and cylindromas are particularly distressing to sufferers. Conventional treatment can be followed by recurrence. We report a case with disfiguring trichoepithelioma treated with erbium:Yag and CO2 laser, achieving a good cosmetic result without recurrence after 2 years. Brooke-Spiegler syndrome and its treatment are reviewed.
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Epidermal naevi are common and can cause marked cosmetic disability. Ablative laser treatment may be successful in their removal, but may result in significant scarring. Surprisingly the erbium:YAG laser is rarely reported for this indication even though it produces minimal tissue damage. We report our experience using this laser to treat six patients with epidermal naevi. Patients (five female, one male; aged 4-41 years) underwent treatment with pulsed 2940 nm erbium:YAG laser at 0.4-0.45 J/cm(2), 2 mm spot size at 4 pulses/s. All six patients had excellent cosmetic results at follow up ranging from 6 to 60 months. The favourable results were dependent on selection of cases with superficial or small, discrete lesions which could be ablated accurately. The erbium:YAG laser is therefore an effective treatment for relatively nonverrucous or papular epidermal naevi.
Non-invasive skin imaging techniques have proliferated over the last decade. Whilst most have a research role, some are routinely used in dermatology clinics. Of these, the skin surface microscope (dermatoscope), a diagnostic aid for pigmented lesions, has had most clinical impact. Such devices, when linked to a videomicroscope for computer analysis, have been dubbed as 'mole scanners'. Mole scanners are increasingly available on a commercial basis even though computer diagnosis of pigmented lesions is currently no better than diagnosis by human experts. Meanwhile, other imaging techniques, such as high-resolution ultrasonography, spectroscopy and optical coherence tomography, may yet find a role in diagnosis and disease monitoring.
BACKGROUND: In the South-west Thames region there were an unprecedented number of lichenoid tattoo reactions to red ink in patients who had visited a local tattoo parlour. The red ink was found to contain mercuric sulphide, a compound known to cause allergic reactions. Topical Dermovate (clobetasol propionate 0.05%, GlaxoWellcome) ointment alone had little impact. OBJECTIVES: To investigate whether the Q-switched 532 nm Nd:YAG laser could produce permanent flattening of the reaction. METHODS: This was an open nonrandomized clinical trial. Biopsies were taken from the lichenoid areas within the tattoos. Subjects were patch tested to 1% ammoniated mercury in petrolatum prior to treatment with the Q-switched 532 nm Nd:YAG laser. Laser treatments were delivered at 6-weekly intervals by a single operator. Patients also applied topical Dermovate between treatments. Therapy was discontinued when the lesions flattened. Clinical photographs were assessed at baseline and prior to each laser treatment. RESULTS: Seven patients with Fitzpatrick skin types I-III were enrolled in the study (four females, three males, mean age 39 years). All patients completed the trial. Patch testing to mercury was universally negative at 48 and 96 h. Substantial flattening and depigmentation of the red ink within the tattoos was noted after six laser treatments. No adverse effects were recorded. CONCLUSIONS: The Q-switched 532 nm Nd:YAG laser in combination with topical Dermovate ointment is a safe and effective method of treating red ink tattoo reactions.
Skin cancer is increasingly common, and the skills involved in its diagnosis should be promoted in UK medical schools. However, there has been no scientific evaluation of the teaching methods employed by dermatology departments. The aim of this study was to evaluate, using traditional audiovisual methods, the impact of an illustrated booklet on skin cancer, coupled with a lecture, on undergraduates' diagnostic skills. The ability of 27 final-year medical students to recognize a variety of skin lesions, using projected images from clinical slides, was assessed. They were tested without warning on two occasions. Immediately after the first test, students were given an illustrated booklet on skin tumours and pigmented lesions which was supplemented with a lecture based on the booklet. Two weeks later, a second test was employed using a series of slides deemed to be of equal diagnostic difficulty. Our results showed a significant increase in the median number of correct diagnoses between the first and second tests (P < 0.001). However, there remained wide variation at the second test in the percentage of correct answers (30 to 80%) amongst students. Our study highlights the need to develop effective methods for improving the diagnostic skills of undergraduates in dermatology, and the importance of evaluating teaching methods. The methods of evaluation, such as ours, can be simple and inexpensive.
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Ultrasound is widely used in general clinical medicine for non-invasive internal imaging. Over the last twenty years, technological advances have enabled the application of high-resolution ultrasonic imaging to the skin. Equipment and hardware is now available to produce cross-section images and three-dimensional reconstructions of selected skin segments. Resolution in vivo is not comparable to light microscopy but continues to improve with superior transducer designs. Skin ultrasonography has been reliably employed as an imaging modality in experimental designs, its quantifiable parameters being a distinct advantage. In particular, increased water content of the upper dermis, as occurs in inflammatory conditions or as a result of photodamage, can be demonstrated clearly as an echo-poor zone. Thus, the future of high-resolution ultrasound (HRU) may reside in its experimental role in monitoring inflammatory or photodamage processes in response to novel treatments. With regard to skin tumours, HRU reliably measures tumour thickness and also holds promise as a differentiator between seborrhoeic keratoses vs. melanoma and benign naevi vs. melanoma. While largely an experimental tool, the potential as an accurate, quantitative and reliable diagnostic and monitoring aid, merits further attention with an emphasis on clinical outcome measures.
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We report a case of unusually severe, scrotal lymphangiomas that have been treated successfully with the novel combination of cutting diathermy and carbon dioxide laser.
BACKGROUND: Elongated and tortuous capillary loops are distinctive features of psoriasis. The significance of these microvascular changes in the pathogenesis of plaques, however, remains unclear. OBJECTIVES: To determine what part the expanded superficial capillary bed plays in the pathogenesis of clinical lesions by selectively thermolysing psoriatic capillaries with a pulsed dye laser (PDL). METHODS: Cutaneous lesions were biopsied before and after treatment and sections assessed by standard immunohistochemical techniques for changes in known indicators of angiogenesis, including endothelial surface area, endothelial cell proliferation and endothelial cell expression of adhesion molecules. We also measured lymphocytic infiltration and epidermal thickness, and quantified the presence of a marker of keratinocyte proliferation before and after treatment. RESULTS: The effect of the PDL was limited to the superficial capillary bed, with no changes in the microvessels (including venules and arterioles) of the upper reticular dermis. Although there was significant clinical improvement in plaques after treatment (P = 0.02), complete clearance of lesions was not achieved. Thermolysis of psoriatic capillaries caused a reduction in both endothelial surface area (P < 0.01) and endothelial cell proliferation in the superficial dermis (P = 0.04). Endothelial expression of surface adhesion molecules (integrins and E-selectin) important in angiogenesis was not, however, altered by treatment. The CD4+ and CD8+ T-cell infiltrate was significantly reduced in the superficial papillary dermis (P = 0.02 and P = 0.04, respectively), but not in the epidermis or upper reticular dermis. Laser treatment significantly reduced epidermal thickness (P = 0.001), but did not alter epidermal keratinocyte proliferation (P = 0.2). CONCLUSIONS: The results demonstrate that dermal capillary changes alone are unlikely to be causal in psoriasis. They indicate that the expanded psoriatic capillaries may be important in facilitating the access of activated T cells to the skin and in maintaining the psoriatic plaque. These results do not refute the consensus view that plaque formation may be mediated by the release of growth factors/cytokines from activated epidermal T cells/keratinocytes.
BACKGROUND: There are potential clinical benefits if non-invasive methods can be used to diagnose or exclude melanoma. OBJECTIVES: We investigated high-resolution ultrasound (HRU) as a potential non-invasive diagnostic aid for pigmented skin lesions. METHODS: Using a 20-MHz ultrasound B-scan imaging system interfaced to a computer, we assessed acoustic shadowing and entry echo line enhancement (EEE) for 29 basal cell papillomas (BCPs) and 25 melanomas. Acoustic shadowing was estimated by the dermal echogenicity ratio (DER), comparing mean echogenicity below the lesion with that of adjacent dermis. Histological features were scored independently. RESULTS: DER < 3 correctly distinguished melanoma from BCP with 100% sensitivity and 79% specificity. Specificity increased to 93% if the presence of EEE was included as a discriminator. Shadowing correlated most significantly with histological extent of hyperkeratosis (P < 0.0001). Consequently, this method falsely identified non-keratotic acanthotic BCP (n = 3) as melanoma. Highly significant differences between benign naevi (n = 15) and melanomas (n = 24) were found. The SD of retrolesional echogenicity was higher for naevi than melanomas (P < 0.0001), but such an analysis was poorly specific for the diagnosis of melanoma (30%). CONCLUSIONS: Overall, HRU has considerable potential as a high-performance screening tool to assist in the discrimination between BCP, but not benign naevi, and melanoma. In particular, it may be possible to exclude melanoma with 100% certainty in the differentiation of BCP from melanoma.
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