Dover J S, Smoller B R, Stern R S, Rosen S, Arndt K A
Department of Dermatology, Beth Israel Hospital, Boston, MA.
Arch Dermatol. 1988 Aug;124(8):1219-24.
Low-fluence carbon dioxide (CO2) laser irradiation of skin has previously been shown to induce damage limited primarily to the epidermis. To evaluate whether this technique was therapeutically effective for pigmented epidermal lesions, ten lentigines caused by methoxsalen and ultraviolet light therapy were treated in one patient using the CO2 laser at fluences ranging from 3.0 to 7.7 J/cm2 for 0.1-s exposures with 4.5-mm spot size. Based on substantial clearing in seven of ten lesions treated, 146 solar lentigines were treated in five patients at fluences of 3.0, 3.7, or 4.4 J/cm2. Biopsies were performed on a total of 30 lesions immediately and 24 hours, seven days, and six weeks after irradiation. Of 125 lesions followed up clinically for six weeks, 12 cleared completely, 81 lightened substantially, and 28 remained unchanged. Only two demonstrated atrophic change. Hyperpigmentation or hypopigmentation did not occur. All lesions that improved had been treated at 3.7 or 4.4 J/cm2. Immediate histologic injury consisted of vacuolar and spindly change and subsequent vesiculation limited to the basilar epidermis. Twenty-four hours later there was epidermal necrosis with regeneration, 0.1 mm of dermal basophilia and stromal condensation, and a mild inflammatory infiltrate. These alterations were dose-dependent, with near complete epidermal necrosis and superficial dermal involvement at the highest fluence, and only focal epidermal necrosis at the lowest. At seven days, epidermal regeneration was complete with traces of melanin remaining in keratinocytes. Melanophages first appeared at seven days and persisted at six weeks, by which time the inflammatory infiltrate had cleared. No lentiginous proliferation was evident and epidermal pigmentation had become normal. Low-fluence CO2 laser irradiation is an effective means of damaging the epidermis with only minimal dermal change. This mode of therapy is an effective way to lighten the pigmentation of lentigines without substantial scarring.
先前的研究表明，低能量密度的二氧化碳（CO2）激光照射皮肤主要会导致仅限于表皮的损伤。为了评估该技术对色素性表皮病变的治疗效果，对一名患者使用CO2激光，在光斑大小为4.5毫米、曝光时间为0.1秒、能量密度范围为3.0至7.7 J/cm2的条件下，治疗了10处因甲氧沙林和紫外线疗法引起的雀斑样痣。基于10处治疗病变中有7处明显消退，对5名患者的146处日光性雀斑样痣在能量密度为3.0、3.7或4.4 J/cm2的条件下进行了治疗。在照射后立即以及24小时、7天和6周对总共30处病变进行了活检。在临床上随访6周的125处病变中，12处完全消退，81处明显变淡，28处保持不变。只有2处出现萎缩性改变。未发生色素沉着过度或色素沉着不足。所有改善的病变均在能量密度为3.7或4.4 J/cm2的条件下进行了治疗。即刻组织学损伤包括空泡样和梭形改变以及随后仅限于基底表皮的水疱形成。24小时后出现表皮坏死并伴有再生，真皮嗜碱性变0.1毫米以及间质浓缩，并有轻度炎症浸润。这些改变是剂量依赖性的，在最高能量密度下几乎完全是表皮坏死和真皮浅层受累，在最低能量密度下只有局灶性表皮坏死。7天时，表皮再生完成，角质形成细胞中残留有微量黑色素。噬黑素细胞在7天时首次出现并持续至6周，此时炎症浸润已消退。未发现雀斑样增殖，表皮色素沉着已恢复正常。低能量密度CO2激光照射是一种仅引起最小程度真皮改变而损伤表皮的有效方法。这种治疗方式是减轻雀斑样痣色素沉着而无明显瘢痕形成的有效方法。
