Yellow-brown Papules on the Cheeks and Limbs of a Male Infant: A Quiz.

An otherwise healthy 10-month-old male infant presented with a 2-month history of slightly itchy yellow-brownish papules, which were most evident on his cheeks (Fig. 1a). Examination revealed further papules on his arms (Fig. 1b) and trunk. His family history was inconspicuous. Blood tests, including full blood count, liver-function, kidneyfunction and C-reactive protein level, were within normal limits. Hepatitis B and Epstein-Barr virus (EBV) serology were negative. Topical steroid and antibiotic therapy had no clinical benefit. Due to persistent papules a lesion on the arm was biopsied 2 months later. Histopathology revealed a dermal infiltrate of non-epidermotropic histiocytes admixed with some lymphocytes (Fig. 2a). Histiocytes stained positive for CD68 (Fig. 2b) and S100 (Fig. 2c) and lacked expression of CD1a and langerin (CD207). Proliferative activity (Ki67) was low.