This patient went on to have a biopsy. Histopathology revealed infiltration of the lesions by sheets of foamy histiocytes (xanthogranulomas) with plenty of multinucleated giant cells including Touton giant cells and chronic inflammatory cells rich in mature lymphocytes and few plasma cells with traversing short bands of spindle fibroblast-like cells. Findings were felt to be consistent with Langerhans cell histiocytosis.

Editorial note: 

It is important to note that Touton giant cells are typically rare in Langerhans cell histiocytosis and thus the diagnosis in this instance should be questioned. Unfortunately, histological images and additional pathological investigations (e.g. electron microscopy) have not been provided. The diagnostic certainty has therefore been reduced to possible. 

Langerhans cell histiocytosis is a systemic disorder involving the monocyte-macrophage system usually represent a systemic manifestation. CNS manifestation includes bony, intracranial hypothalamic-pituitary axis and pineal region, intracranial intra-axial lesions. The above case was initially diagnosed radiologically as CNS lymphoma or metastases.