RESUMO
Drug hypersensitivity is an unpredictable, immunologically mediated adverse reaction, clustered in a genetically predisposed individual. The role of "hapten concept" in immune sensitization has recently been contested by the "pharmacological interaction" hypothesis. After completion of the "human genome project" and with the availability of high-resolution genotyping, genetic susceptibility to hypersensitivity for certain drugs has been proved beyond doubt though the trend is ethnicity and phenotype dependent. Application of this newly acquired knowledge may reduce or abolish the morbidity and mortality associated with cutaneous drug hypersensitivity.
RESUMO
Melanoacanthoma denotes a rare variant of pigmented seborrheic keratosis. A 65-year-old male farmer had pigmented, verrucous, itchy, highly painful, progressively growing irregularly oval plaque on left side of lower back for the past five years. The indurated lesion, measuring maximum diameter 10 cm × 5 cm, had no discharge, bleeding, ulceration, or associated lymphadenopathy. Dermoscopy showed regular pigmentary network and cribiform pattern of ridges without any feature of malignant melanoma. Histopathology showed well-defined islands of basaloid cells interspersed with large and richly dendritic melanocytes. The lesion was totally excised followed by skin grafting. Our patient was unique in its massive size and clinical resemblance with malignant melanoma. The diagnosis was confirmed by dermoscopy and skin biopsy.
