Halo Nevi – A Decade of Surgical Experience in Southern Israel

摘要

Background: Halo nevi are defined as benign melanocytic nevi that are surrounded by a rim of depigmentation, resembling a halo. This phenomenon often indicates the beginning of involution and subsequent regression of the melanocytic nevus, a process that extends over a period of several months. The consensus is that the central lesion should be evaluated and biopsied if there is clinical suspicion of dysplasia or malignancy.Objectives: To determine the characteristics of halo nevi excised in southern Israel during a decade.Methods: The Soroka University Medical Center is the regional hospital of southern Israel with its pathology institute evaluating all of the cutaneous lesions excised in the Soroka University Medical Center and most of the outpatient clinics in the region. We conducted a retrospective study compiling demographic and histopathological data from the institute's computerized system on all patients that underwent an excision of a cutaneous lesion that later was diagnosed histopatholgically as a halo nevus between the years 1996 and 2005. Results: Thirty six lesions were diagnosed as halo nevi, with characteristics similar to previous publications. Two of the 36 lesions were not clinically suspicious for dysplasia but were histologically diagnosed as dysplastic nevi. Conclusions: The clinician should evaluate the central lesion as suggested in previous publications, albeit with a higher level of suspicion for dysplasia, since the halo phenomenon and the regression of the pigmented nevus may interfere with accurate clinical diagnosis. Introduction Halo Nevi (HN), also termed Sutton nevi, leukoderma acquisitum centrifugum, or halo phenomenon, are defined as benign melanocytic nevi that are surrounded by a rim of depigmentation, resembling a halo [1-5]. HN usually appear on the back and are common in children and young adults, with a mean age of onset at 15 years [5-7]. The incidence of HN in the population is estimated to be approximately 1% and there is no predilection for sex or race [1, 8]. Multiple lesions are found in about 50% of the cases, occurring either simultaneously or successively. The halo phenomenon often indicates the beginning of involution and subsequent regression of the melanocytic nevus, a process that extends over a period of several months [5]. The term HN is classically applied to the first stage of clinical development, i.e., a pigmented nevus with a surrounding rim of depigmentation. In stage II, the central nevus loses its pigmentation and appears pink with a surrounding halo. In stage III the central nevus disappears leaving only the circle of depigmentation, and in stage IV the depigmented area undergoes repigmentation, with no trace of its prior existence over a period of months or even years [5, 9]. Histologically, the depigmentation in the halo is caused by destruction of melanocytes. The degree of depigmentation and melanocytic necrosis is associated with the number of leukocytes, mainly CD8-positive T lymphocytes and monocytes, that infiltrate the halo [10]. Thus, these cells are thought to be the effectors in the destruction of the melanocytes.The halo phenomenon is most common in benign melanocytic nevi but it may also be observed in other benign or malignant neoplasms such as blue nevi, Spitz juvenile nevi, neurofibromas, seborrhoeic keratoses, dermatofibromas, basal cell carcinomas and malignant melanomas [5, 7, 11-13]. Therefore, the consensus is that the central lesion should be evaluated and biopsied if there is clinical suspicion of nevus dysplasia or malignancy [7].Mooney et al examined the histopathology of 142 lesions excised in the United States that were given the clinical or histologic diagnosis of a HN. All but 3 were found to be compound, junctional, or intradermal nevi with a broad spectrum of atypia [11]. The southern region of Israel is characterized by one central regional medical center with a single pathological department that handles most if not all the biop