A woman in her 20s presented with numerous grouped yellow-brown and red-brown papules on the upper eyelids, infraorbital rims, bilateral axillae, inframammary creases, lower back, buttocks, hips, inguinal folds, and proximal thighs (Figure , A and B). The lesions first appeared in her right axilla 6 months prior and were asymptomatic. The patient also noted a 3-month history of polyuria, polydipsia, and nocturia. Review of symptoms was otherwise negative. She had no notable medical or family history. On physical examination there were no other sites of involvement including mucosal surfaces. Shave biopsies were obtained from the right (Figure , C) and left axillae (Figure , D) and sent for histopathological examination. Yellow-brown papulesA Red-brown papules B Hematoxylin-eosin C CD68 stain D Figure. A, Clinical images show punctate yellow-brown papules on the upper eyelids and infraorbital rims; B, numerous red-brown papules in the right axilla. C, Histopathology of a shave biopsy sample from the right axilla (original magnification ×200). D, Histopathology of a shave biopsy sample taken from the left axilla (original magnification ×200). WHAT IS YOUR DIAGNOSIS? A. Xanthogranuloma B. Erdheim-Chester disease C. Xanthoma disseminatum D. Generalized eruptive histiocytoma Clinical Review & Education