This article is an answer to the Case – Infant with “Blueberry Muffin” Rash
A biopsy specimen of the skin obtained from the right thigh showed a dense infiltrate of histiocytes with grooved, kidney-shaped nuclei. Immunohistochemical staining of the specimen was positive for S100+ CD1a+ and negative for CD43 and myeloperoxidase, findings that confirmed a diagnosis of skin-limited congenital Langerhans-cell histiocytosis.
Because of the lack of extracutaneous involvement, the lesions were expected to resolve without treatment. At follow-up 6 weeks after delivery, the skin lesions had resolved. The infant continues to be followed for signs of recurrence.