Langerhans Cell Histiocytosis of the Bone Presenting as Back Pain: An Unusual Diagnosis for a Common Complaint.

Langerhans cell histiocytosis (LCH) is a rare disease entity characterized by histiocyte infiltration of various organ systems with abroad spectrum of clinical manifestations and prognosis, ranging from benign and self-limiting to lethal. We report a case of a healthy 29-year-old male who presented with upper back pain that was unresponsive to over-the-counter analgesics. The painwas eventually attributed to a single lytic lesion at the posterolateral aspect of his seventh rib, consistent with LCH of the bone. Our patient's symptoms subsided without any surgical intervention apart from a biopsy that was performed for diagnostic purposes. His lytic lesion eventually regressed, and he has remained asymptomatic at follow-up. We provide a brief review of literature on diagnostic approach, guidelines, and treatment modalities for adults diagnosed with LCH of the bone, a rare diagnosis most frequently presenting with a common complaint such as back pain.