Author: darrendkies

Darren Kies • UNC Chapel Hill

Aunt Mickey (They Look the Same until You Undress Them). Calvarial Metastases or Something Else?

A 59 year-old woman presented with an approximate one-year history of worsening sensory disturbances and pain in the right side of her scalp and face.  Her past medical history was otherwise unremarkable.  Part of her initial work-up involved imaging of the head, which revealed multiple lytic lesions of varying sizes throughout the skull.    An unenhanced CT was done (Figure 1), and several circumscribed lytic lesions of varying sizes were seen throughout the calvarium.  There was no periosteal reaction or sclerosis surrounding the lesions.  There were no intracranial lesions. The patient was referred to a neurosurgeon for biopsy because no underlying primary tumor was found.

Pre-operative CT
Figure 1 - Axial CT image of the head, bone windows, demonstrates lytic lesions in the posterior calvarium with thinning of the inner and outer tables.

She continued to have similar symptoms post-operatively that prompted MR imaging of the brain (Figure 2). The images demonstrate several well-demarcated lesions that were T1 hypointense and T2 hyperintense when compared to bone marrow, with severe thinning of the adjacent cortex.  No intracranial lesions were present.  A T1 hyperintense right subdural collection was due to the recent surgery.

Figure 2 - T1 (left) and T2 (right) weighted axial MR images of the brain demonstrate several calvarial lesions that are T1 hypointense and T2 hyperintense when compared to normal bone marrow.

The differential diagnosis for multiple lytic lesions in the adult skull includes primarily metastatic disease and multiple myeloma.  Others include epidermoids, burr holes and in children, the histiocytoses.

What is your diagnosis?  Are there other rare causes of lytic osseous lesions in the skull?

The patient underwent a right frontal skull biopsy.  Pathology revealed non-caseating granulomatous inflammation, consistent with sarcoidosis.

Sarcoidosis is a multisystemic inflammatory disorder of unknown cause that is best known for pulmonary, lymph node, and cutaneous involvement.  …