Haematoxylin-eosin–stained sections demonstrated a moderately dense infiltrate of lymphohistiocytic cells extending from the papillary to the midreticular dermis. Immunocytochemical staining of the lymphocytic infiltrate revealed a predominance of T cells, but some B cells were also identified. Many of the cells stained with the histiocytic markers Mac-387 and CD68. Staining was negative for S100 protein.
On electron microscopy, a population of histiocytes was identified, but no Birbeck granules (specific for Langerhans cells) were present. Dense bodies and comma-shaped bodies were identified in some of the cells.
Multiple Self-healing Erythematous Papules in an Adolescent—Diagnosis. Arch Dermatol. 2003;139(7):933-938. doi:10.1001/archderm.139.7.933-a