Skull eosinophilic granuloma

Case contributed by Dr Bruno Di Muzio

Presentation

Incidental finding on CT scan for trauma.

Patient Data

Age: 28
Gender: Male
CT

CT Brain and facial bones

No evidence of acute ischaemia. No intra or extra-axial haemorrhage is seen. Ventricles and sulci are within normal limits for age.

A fracture runs through the alveolar ridge of the maxilla with posterior displacement of teeth 21 and 22 (left upper central and lateral incisor). The fracture line extends into the anterior nasal spine.

Lesion within the posterior left parietal bone abutting the lambdoid suture is favoured to represent an eosinophilic granuloma; DDx intraosseous epidermoid. Metastases or lymphoma are unlikely. MRI is suggested for further characterisation.

MRI

MRI Brain

 

There is a posterior left parietal bone defect measuring 20 mm in its transverse dimension with destruction of both inner and outer tables (inner table is more affected). This defect is occupied by a non expansible soft tissue lesion which shows low to iso signal on T1, central low T2 signal, and peripheral enhancement. There is no evident restrict diffusion. The lesion does not extend or abut intra or extra-cranially. No other calvarial lesions are seen.

Appearance and intensity of brain parenchyma, brainstem or cerebellum are normal.

Ventricular system and cisternal spaces appear normal.

No evidence of intracranial space occupying lesion or obvious vascular anomaly is detected.

There is no shift of the midline structures.

Conclusion:

Focal left parietal skull bone lesion with benign imaging characteristics and most likely representing an eosinophilic granuloma.

Annotated image

Annotated images demonstrating the skull vault hole in the right parietal bone/parieto-occipital suture. MRI images depicting the larger inner table defect when compared to the external table. 

Case Discussion

This incidental skull lesion has definitely benign imaging features and is more likely to represent and eosinophilic granuloma. Features such as: 

  • solitary punched out lytic lesion without sclerotic rim
  • greater involvement of the inner than the outer table (hole within a hole) sign
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Case information

rID: 39187
Case created: 25th Aug 2015
Last edited: 30th Aug 2015
Tag: rmh
Inclusion in quiz mode: Included

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