A neonate with Langerhans cell histiocytosis presenting as blueberry muffin rash: Case report and review of the literature.

In our case report, we discuss a 1-day-old boy presenting with blueberry muffin syndrome diagnosed with Langerhans cell histiocytosis. The diagnosis complicated by an initial difficult-to-interpret biopsy showing only a hint of perifollicular CD1a-positive cells; however, given our team's strong clinical suspicion of Langerhans cell histiocytosis, a second biopsy of a more mature lesion was done and showed typical histopathology. This case introduces the possibility of perifollicular Langerhans cells early in this condition, demonstrates the importance of appropriate biopsy site selection, and highlights the importance of maintaining a high degree of suspicion when there is poor clinicopathologic correlation. Our case report contains a comprehensive table which reviews the systemic and cutaneous clinical features, as well as the laboratory, pathology, and imaging findings for the differential diagnoses of blueberry muffin baby.