Delayed Diagnosis of Langerhans Cell Histiocytosis: A Case Series

Background: Langerhans Cell Histiocytosis (LCH) is a rare clonal proliferative disease affecting the dendritic-derived, antigen-presenting Langerhans cells. Formerly termed Histiocytosis X, LCH encompasses a wide constellation of symptoms that range from solitary bone lesions to multi-system involvement. Because of the variable presentation of LCH, the path to diagnosis can be delayed as this disorder is potentially confused with other disease processes. Definitive diagnosis of the disease is made histologically with positive staining of CD1a or Langerin, which are proteins specific to the aberrant cells. This case series considers LCH in the setting of pediatric patients with solitary bone lesions. Case Information: Three pre-teen patients initially presented to primary care with long-term pain and decreased activity in the absence of other systemic symptoms or trauma. Single, well circumscribed lucent lesions were subsequently identified via radiograph. Following surgery, pathology reports did not initially indicate the presence of LCH, and all cultures were negative. In each case, initial diagnoses of chronic osteomyelitis were given. When CD1a and Langerin staining were applied in retrospect, staining for all three patients was positive in small clusters of cells. Final diagnoses of LCH, fibrosing phase, were eventually assigned and the prolonged clinical history accounted for the amount of fibrosis present in the tissue samples. Conclusions: Because of the variable presentation of LCH, diagnosis can be potentially be delayed. These cases are important because they bring attention to a potential presentation of LCH as gradually occurring bone pain caused by solitary bone lesions. In such cases, surgery can be curative and often no further treatment will be required. It is important to distinguish LCH from chronic osteomyelitis, especially in pediatric patients, as correct and early identification of the disease prevents the hassle, expense, and danger of unnecessary treatment. Staining with CD1a and Langerin aids in differentiating these diagnoses and should be included in the work up for solitary lucent lesions.