Orbital subperiosteal hematoma

A 40 yo female with 3 month history of left orbital proptosis.

Left eye ball movement painful and restricted. 

No history of trauma.

Here is his MRI Brain Coronal T2, T1w images. Sagittal T1, axial T1w images.

This MRI study of brain shows:

A well demarcated lentiform shaped fluid signal intensity collection in superior quadrant of left orbit, hyperintense on T2, iso to hyperintense on T1.

No septations or loculations.

No destruction of adjacent orbital roof. 

Left orbital proptosis. 

Histopathology : Orbital subperiosteal hematoma

It's strange, an Orbital subperiosteal hematoma without history of trauma. The whole study reviewed again and revealed an associated adjacent ethmoid sinus mucocele. 

Orbital subperiosteal hematomas can develop associated with sinus infection. Such a condition should be treated as a sinusitis complication and the associated sinus infection must be treated concomitantly (Reference : Orbital subperiosteal hematoma associated with sinus infection; Rhinology. 2010 Mar;48(1):117-22; Park HW, Lee BJ, Chung YS)