A Clinical Study of Congenital Melanocytic Naevus.

INTRODUCTION : Naevus is a Latin word which means maternal impression or birth mark. Naevus is a common skin lesion seen in patients of all ages and both sexes.It is usually present at birth or in early childhood. However, some may develop later in adulthood. Hamartoma is a Greek word which means to err. Hamartoma is a tumour like, non neoplastic proliferation of abnormal mixtures of the normal components of a tissue. Previously naevus and hamartoma were considered to be synonymous but now they are regarded as distinct entities as there is no neoplastic proliferation in hamartoma whereas in naevus neoplastic proliferation occurs. Naevi are of cosmetic significance if they are large and located on visible areas of the body.Their importance also lies in associated defects of organ systems and possible neoplastic potential, benign and malignant. There are several types of naevi .Based on the tissue of origin, they are classified as epidermal naevi, melanocytic naevi, dermal and subcutaneous naevi. Melanocytic naevi are benign neoplasms or hamartomas composed of nevomelanocytes. They are broadly classified based on their being derived from epidermal melalanocytes or from dermal melanocytes. Congenital and acquired melanocytic naevi are derived from epidermal melanocytes while naevus of Ota, naevus of Ito and blue naevi are derived from dermal melanocytes. Congenital melanocytic naevi are anomalies in embryogenesis. They could be considered as malformations or hamartomas, made up of nevomelanocytes which lack normal melanocytic differentiation and occur as ‘nests’ in the epidermis and /or dermis. In this study the age and sex distribution of congenital melanocytic naevi, types of congenital melanocytic naevi, localization , their cutaneous or systemic associations if any, complications, skin biopsy, special staining and treatment of congenital melanocytic naevi were studied. AIM OF THE STUDY : 1. To study the presenting age group and sex distribution of congenital melanocytic naevus. 2. To study the different clinical types of congenital melanocytic naevus. 3. To study the localization of congenital melanocytic naevus. 4. To evaluate the associated cutaneous and systemic conditions of congenital melanocytic naevus. 5. To study the complications of congenital melanocytic naevus. CONCLUSION : The sex distribution of congenital melanocytic naevus was more in females than males in this study. * Congenital melanocytic naevus is classified based on the size of the lesion as small, medium, large, and giant naevus.In this study prevalence of small naevi was more ,followed by medium, giant and large naevi in descending order of * Localisation of small naevi were more on the head and neck region, whereas medium naevi were homogenously distributed in the head and neck ,and chest and back region in this study. * In this study, most of the small congenital melanocytic naevi were single in distribution rather than multiple. * Kissing naevus of the eyelid (Congenital divided naevus ) which falls into the group of medium and large naevus was found in 3 cases which shows the time of development of congenital melanocytic naevi. * Giant naevi of bathing trunk distribution and localization over the head and neck region, posterior axis were noted both in children and adults.CT scan of these patients were normal and involvement of central nervous system was not found in any of these cases