Lichen planus pigmentosus inversus
A twenty-five year old male patient, brown-skinned, informed that for the past 9 months\nhe had noticed the appearance of asymptomatic brown spots, on the cervical region,\naxillary, inguinal and popliteal folds. He denied the appearance of other cutaneous\nlesions, pruritus, systemic symptoms, previous diseases or the use of illicit drugs or\nmedications. On examination, we observed hyperchromic, smooth-surfaced macules, with\nwell-delimited edges, measuring from millimeters to centimeters in diameter and often of\nan oval shape ( to ). There were not other lesions either on skin, nails, scalp, or\nmucosae, nor signs of lymphadenomegaly.\nOver the affected skin areas, the direct exams and cultures for fungi and bacteria were\nall negative. Complete blood counts, liver tests and electrolyte results were all within\nthe normal range. Hepatitis C serology was negative. Anatomopathological exams of the\nlesions were performed from distinct samples (right and left axilla), and repeated on a\nthree-month interval with identical characteristics: discreet rectification of\nepithelial cones in the epidermis, irregular hydropic degeneration on the basal layer,\nmarked pigmentary incontinence with the presence of melanophages on the superficial\ndermis and light to moderate inflammatory lymphocytic infiltrate surrounding the\ncapillary vessels of the papillary and reticular dermises ( and ).\nBased on the clinical and histopathological features we reached the diagnosis of lichen\nplanus pigmentosus inversus. Afterwards, we initiated treatment with systemic corticoid\nusing prednisone 20mg/day for 30 days, without any therapeutic response. After four\nmonths, without any further treatment, the patient presented with a discreet improvement\non the cervical and popliteal regions, whilst axillary lesions remained unaltered.