[Eruptive melanocytic nevi during azathioprine therapy in myasthenia gravis]

Distribution Patterns (7B Rule) and Characteristics of Large Congenital Melanocytic Nevi: A Retrospective Cohort Study in China

Large congenital melanocytic nevus has a high risk of malignancy. However, few studies have summarized its characteristics, treatments, outcomes and malignancy incidence in Chinese patients. This paper reviews a retrospective cohort study evaluating 1,171 patients from Shanghai Ninth People's Hospital between 1 January 1989 and 31 August 2019 using electronic medical records and phone calls to collect clinical and pathological data in which 133 patients were diagnosed with a large congenital melanocytic nevus. Three patients relapsed, and none developed melanoma among the qualified patients. Besides, a new “7B” rule for distribution patterns of large congenital melanocytic nevi was proposed, including bonce, bolero, back, bathing trunk, breast/belly, body extremity, and body. The most common distribution pattern of large congenital melanocytic nevi was bonce, and all blue nevi distributed as bonce. Statistical analysis showed a significant difference (P = 0.0249) in the “7B” patterns between the melanocytic nevus and the neuronevus. In conclusion, the malignancy rate of large congenital melanocytic nevi is much lower in China than in other regions and people of other races. The pathology of large congenital melanocytic nevus may decide its “7B” distribution pattern.

Drug-induced eruptive melanocytic nevi

INTRODUCTION

The sudden eruption of melanocytic nevi has been associated with a number of conditions, such as bullous skin diseases, immunodeficiency and immunosuppression. The exact mechanisms leading to the development of eruptive melanocytic nevi are unknown. Areas covered: The aim of this article is to review the literature concerning eruptive melanocytic nevi following the administration of immunosuppressive drugs and other medications. Expert opinion: The literature regarding the development of eruptive nevi in association with pharmacological therapies includes a relatively low number of reports. Prevalence of this phenomenon is likely to be underestimated, thus reporting should be encouraged in order to better define the actual significance and related clinical implications. The development of multiple melanocytic nevi during immunosuppressive treatments highlights the importance of immune system integrity in the regulation of nevi growth. The observation of eruptive nevi as an unexpected effect of targeted therapies for specific types of cancer, including melanoma, provided intriguing hints to understand the mechanisms underlying this paradoxical event. The synergistic role of additional triggers in the occurrence of drug-induced eruptive nevi has not been explored and may be an interesting area of research.