Incidental Malignant Melanoma: Clinical And Pathological Characteristics

摘要

Background. The incidence of cutaneous malignant melanoma (CMM) is rising worldwide and so is its morbidity and mortality. We define the term incidental malignant melanoma (IMM) to describe a lesion referred to surgical treatment with clinical diagnosis other than melanoma or dysplastic nevus.Objectives. The goal of this study is to assess incidence and characteristics of incidental melanomas, to explore the reasons for such a diagnosis failure and possible ways of preventing it. Methods. This is a retrospective study of 173 skin lesions diagnosed as CMM in 1996-2004. 28 lesions were IMM (16.2%).Results. IMMs were strongly associated with high Breslow and Clark level and community clinic versus hospital setting as the primary diagnosing site.Conclusions. We found a high percent of IMM in our patient population. This group of high-risk patients is prone to delayed definitive treatment and possible worse prognosis.In view of acute increase in CMM incidence a higher suspicion attitude of not only pigmented skin lesions should be implemented especially in community services. Introduction The incidence of cutaneous malignant melanoma (CMM) is rising worldwide and so is the morbidity and mortality. CMM constitutes approximately 11% of all skin cancers [1] but it is associated with a significantly higher mortality than non-melanoma skin cancer [2, 3].Early detection of this tumor is crucial for proper and opportune treatment of patients. An early, timely treatment of CMM reduces morbidity and mortality significantly.There are two main reasons for delays in treatment of CMM: Delayed diagnosis: Lag time between appearance of new or changing lesion and first observation by physician (patient delay)Delayed treatment: Timing of final excision of the lesion after the doctor's initial diagnosis (physician delay) [4]. Both factors should be dealt with especially in view of long waiting time at public health services in which defined clinical pre-operative diagnosis dictates surgery schedule. We define the term “Incidental Malignant Melanoma” (IMM) to describe the case of initially misdiagnosed unsuspected CMM lesion that was further diagnosed histo-pathologically as melanoma. The goal of this study is to assess incidence and characteristics of incidental melanomas, to explore the reasons for such a diagnostic failure and possible ways of preventing it. Patients and methods This is a retrospective study of 173 histologically diagnosed CMM removed from 168 consecutive patients diagnosed as CMM between the years 1996-2004. All CMM were excised by consultant and residents plastic surgeons in the Department of Plastic Reconstructive Surgery at Soroka University Medical Center and Community Clinics in Beer Sheva and Negev Region, Israel. These cases were divided into two main groups: 1.Skin lesions clinically suspicious for CMM (Suspicious malignant melanoma – SMM), including dysplastic nevi; 2.Incidental Malignant Melanomas (IMM), misdiagnosed cases with improper clinical diagnosis of benign lesion, BCC or SCC. The histological reports were reviewed for parameters associated with the tumor diameter, its subtype, Clark and Breslow thickness and operating setting (community clinics vs. hospital). Statistical difference for parametric variables was assessed using the Student t-test and for non-parametric variables using chi-squared test. Results 168 consecutive patients underwent excision of 173 CMMs.Twenty-eight lesions out of 173 were IMM (16.2%). The mean age of patients with IMM was 63 ±14.8 years and for SMM 59.6±16.8. In IMM group eleven were males (39.3%) and 17 females (60.7%). Among 140 patients with SMM 71 (50.7%) were males and 69 (49.3%) – females. There was no statistically significant difference between these two groups.120 out of 173(70%) of CMMs were excised in the hospital and 53 out of 173 (30%) in community clinics. IMMs were revealed in 15 out of 120 lesions removed in the hospital (12.5%) and 13 out of 53 (24.5%) in community cl