John Kenealy

Carbon Dioxide Laser Dermabrasion for Giant Congenital Melanocytic Nevi

The management of giant congenital melanocytic nevi remains controversial. There is a balance to be achieved between minimizing the disfiguring appearance of these lesions, both before and after surgical treatment, and limiting the risk of malignant change. A series of seven patients who were treated in the same manner, with carbon dioxide laser dermabrasion, is presented. It has been 6 years since the first patient was treated in this way, and no cases of recurrence have been observed. This technique enables the removal of all or most of the pigmented lesion, with minimal scarring and without the need for disfiguring skin grafts. It has been well proved that there is an increased risk of malignant changes among patients with these lesions, although the amount of increased risk for the patient is not clear. Evidence from a review of the currently available literature is presented to indicate why this management method, at best, should decrease this risk and, at worst, should make no difference to the overall risk for individual patients.

Sub-lethal effects of exposing the human melanoma cell line Skmel−23 to 532 nm laser light

The human melanoma cell line SKmel‐23 has been used to investigate the sub‐lethal damage that can occur as a result of exposing melanin containing cells to light (532 nm) from a frequency doubled Q‐switched (Nd:YAG) laser. A dose response curve was obtained, which indicates that at energy levels of 0.6 J/cm2 and below no effect on either the viability or growth rate of the cell line was observed. Above this, cells rapidly died and at an energy level of 2.0 J/cm2, only approximately 15% of cells survived. This contrasts with the effects on the G361 melanoma line, which contains far less melanosomes, as an LD50 for this cell line was approximately 5.5 J/cm2. Exposing SKmel‐23 cells to 0.4 J/cm2 of 532 nm light results in a diminution of the number of melanosomes within cells as well as a marked decrease in melanin content, as determined by spectrophotometric assay and electron microscopy. Using the reverse transcriptase polymerase chain reaction technique, the reduction in melanin content of the cells was accompanied by a selective decrease in mRNA coding for tyrosinase, the first enzyme in the biosynthetic pathway for melanin. No decrease in the mRNA coding for the GAPDH protein was observed. Our finding has implications for understanding the control processes that regulate the melanin content of cells and suggests that the model described can be used to further investigate changes that may occur in cells as a result of their exposure to sub‐lethal levels of laser light. Int. J. Cancer 72:1104–1112, 1997.

Erythromycin sclerotherapy in the management of seroma

Post-operative seroma can present the clinician and patient with a chronic and difficult problem. The authors present their experience of managing refractory seroma with the antibiotic erythromycin, administered for its properties as a sclerosant. The technique was found, in a series of patients, to be effective, simple and without serious complications.

Periocular lentigo maligna treated with imiquimod

Abstract Topical imiquimod 5% cream has been used successfully to treat eyelid basal cell carcinoma, Bowens disease of the eyelid and eyelid lentigo maligna. We report a case of borderline lentigo maligna on the eyelid that proved difficult to treat with surgery and, when the patient deferred surgery for personal reasons, imiquimod 5% cream was used with complete resolution of the lesion and no recurrence so far over a 3-year period of follow-up. The use of imiquimod in lentigo maligna and around the eye is discussed.

Laser transmission through membranes using the Q-Switched Nd:YAG laser

Many laser centres utilise various transparent membranes during treatment sessions with Q‐switched lasers to prevent or reduce tissue splatter, thereby reducing the aerosolised biohazard of cellular debris to operator and laser.

The detection of tyrosinase mRNA in peripheral blood samples is unlikely to aid in the management of patients with localised malignant melanoma

A number of authors have reported the detection of tyrosinase mRNA in the peripheral blood of patients with malignant melanoma using the reverse transcription polymerase chain reaction (RT-PCR). The precise value of this assay as a prognostic tool, however, remains in doubt. This is particularly so with relation to localised disease, where relatively little data has been accumulated. In this study we analysed the peripheral blood of 50 consecutive patients with primary malignant melanoma referred to a plastic surgical centre with the facility of a pigmented lesion clinic. Samples were analysed from an additional 35 patients with advanced melanoma disease and 35 patients with benign pigmented cutaneous lesions. We were able to identify tyrosinase transcripts in the peripheral blood of only two of 50 patients with localised disease. Of those with more advanced disease, a positive finding was found in three with regional disease and four patients with metastatic spread. Stage of disease was found to correlate significantly with PCR status. No correlation was identified with other prognostic markers or with outcome over a three-year period. This data would support the conclusion that the detection of tyrosinase mRNA in peripheral blood is likely to be of little value as an aid in the management of patients with early malignant melanoma.

Comparison of cooling criteria with a cryogen spray and water/air spray

Skin cooling using a cryogen spray (tetrafluoroethane) has been shown to dramatically reduce the skin surface temperature whilst predictions show that the underlying dermal tissue is unaffected. This technique is repeated with a chilled water spray, along with a continuous airflow to enhance evaporation. Radiometric skin surface temperature measurements are recorded during trials utilizing this technique and the results are compared with theoretical predictions in order to determine the mechanism by which the heat is removed from the skin. The optimum spray conditions are achieved when the water is chilled to around 2 degrees Celsius with a continuous airflow of 50 liters/minute. Under these conditions skin surface temperature reduction is about 8 degrees Celsius - 10 degrees Celsius. The measured radiometric skin surface temperature change indicates that the mechanism by which this process removes heat from the skin is predominantly evaporation. Predictions of skin temperature change with varying skin depth indicate that the optimum spray time is around 100 ms.

The use of nerve blocks in the laser treatment of cutaneous lesions

Lasers are now well accepted as standard treatment for many cutaneous lesions. Many types of laser treatment require pain relief, the choices being general anaesthesia, (particularly in younger patients), or local or topical anaesthesia (EMLA). There have been few reports on the specific use of local anaesthetic nerve blocks in the laser treatment of cutaneous lesions. We present our experience of 816 nerve blocks in 135 patients (53 males, 82 females; age range 5-73 years, median 27 years) during 877 treatment sessions 96% of the nerve blocks provided complete anaesthesia in the required anatomical area. Only 9 (7%) patients (1.1% of the 816 nerve blocks) developed complications that could be attributed to the anaesthetic blockade. We recommend nerve blocks as a safe and efficacious method of anaesthesia during the laser treatment of cutaneous lesions.