Nonmelasma facial melanosis: a prospective, clinical, histopathological and immunohistochemical study

Background: Paucity of literature and non consensus on clinicohistopathological features amongst the nonmelasma facial melanosis for example lichen planus pigmentosus (LPP), pigmented contact dermatitis (PCD), macular amyloidosis, acanthosis nigricans, pigmented demarcation line, post inflammatory hyperpigmentation, etc., make them difficult to diagnose and equally challenging to treat. Materials and Methods: It was a prospective, uncontrolled study, conducted at tertiary hospital at eastern India in 100 patients presenting with facial hyperpigmentation who agreed to undergo 3 mm skin biopsy during Jan 2014 to Jun 2015. Cases of melasma were excluded by clinical, Woods lamp examination and if required dermoscopy. Details of history, physical examination, histopathological examination, and Immunohistochemical studies were recorded. Melan A was used as melanocytic differentiation marker while CD4, CD8 were used as inflammatory markers. Mean ± SD, chi-square test or Fisher’s exact test, degree of agreement by Cohen’s Kappa were calculated. P-value was considered significant if ≤0.05. Results: 44 males and 56 females (56%) (M: F=1:1.24) with mean age of 45.98 years and median duration of illness of 28 months (5 months-13 years) were studied. Out of 43 confirmed cases of PCD, 16 had associated hypothyroidism (chi square 6.11, P-value 0.0134). Maximum patients belonged PCD (n = 47) followed by LPP (n = 27). Maximum concordance of clinical and histopathological diagnosis was present in PCD and LPP (Cohen kappa more than 0.9). Epidermal atrophy and band like inflammatory infiltrate were statistically significant features in LPP (P < 0.001). There was no histopathological and immunohistochemical correlation. Overall, clinical histopathological concordance rate was 77%. Conclusion: Subset of nonmelasma facial melanosis is difficult to diagnose clinically which require further confirmation by histopathological examination. Small number of patients in other groups apart from PCD and LPP and uncontrolled study were major limitations of this study.