An eight year old boy presents with back pain and mild fever. His plain X-ray of the dorsolumbar spine reveals a solitary collapsed dorsal vertebra with preserved disc spaces. There was no associated soft tissue shadow. The most likely diagnosis is -
High-Yield Explanation
Solitary collapsed vertebra (vertebra plana) with preserved disc spaces in a child suggests the diagnosis of Eosinophilic granuloma (a type of Histiocytosis).