EURORAD ESR

Case 14282

A rare case of posterior cranial fossa dermoid cyst with malignant transformation

Author(s)
CHONG Wing Ho1, TSE Po Ki Teresa2, YAM Kwong Yui3, WONG Yiu Chung1

(1) Department of Radiology, Tuen Mun Hospital, Hong Kong
(2) Department of Neurosurgery, Princess Margaret Hospital, Hong Kong
(3) Department of Neurosurgery, Tuen Mun Hospital, Hong Kong
Email:cwh690@gmail.com
 
Patient
female, 48 year(s)
 
 
  • Figure 1
    CT brain with left posterior cranial fossa mass

    CT brain with left posterior cranial fossa mass. A space occupying lesion with intra-lesional calcification and macroscopic fat, mainly extra-axial but its interface with the left cerebellar hemisphere was indistinct.

     
    Area of Interest: Neuroradiology brain; Imaging Technique: CT; Procedure: Computer Applications-General; Special Focus: Cysts;
     
     
  • Figure 2
    CT brain with tiny fat along the left tentorium

    A tiny fat component was seen along the left tentorium. It could be related to rupture of the cyst contents.

     
    Area of Interest: Neuroradiology brain; Imaging Technique: CT; Procedure: Computer Applications-General; Special Focus: Cysts;
     
     
  • Figure 3
    MRI brain - T1W sequence

    T1W shows intralesional hyperintensity, corresponding to the known lipomatous component. The lesion was mainly extra-axial with suspicious component of intra-axial invasion, favouring an aggressive lesion.

     
    Area of Interest: Neuroradiology brain; Imaging Technique: MR; Procedure: Imaging sequences; Special Focus: Cysts;
     
     
  • Figure 4
    MRI brain - T1W sequence

    Tiny T1W hyperintense deposit was noted along the left tentorium, corresponding to the macroscopic fat in CT scan

     
    Area of Interest: Neuroradiology brain; Imaging Technique: MR; Procedure: Imaging sequences; Special Focus: Cysts;
     
     
  • Figure 5
    MRI brain - T2W sequence

    T2W shows intralesional cystic component. Peri-lesional edema with mass effect onto the fourth ventricle was demonstrated.

     
    Area of Interest: Neuroradiology brain; Imaging Technique: MR; Procedure: Imaging sequences; Special Focus: Cysts;
     
     
  • Figure 6
    MRI brain - DWI sequence

    DWI reveals typical restricted diffusion for dermoid cyst.

     
    Area of Interest: Neuroradiology brain; Imaging Technique: MR; Procedure: Imaging sequences; Special Focus: Cysts;
     
     
  • Figure 7
    MRI brain – T1W with gadolinium

    There is heterogeneous intra-lesional gadolinium enhancement. No leptomeningeal enhancement was demonstrated.

     
    Area of Interest: Neuroradiology brain; Imaging Technique: MR; Procedure: Imaging sequences; Special Focus: Cysts;
     
     
  • Figure 8
    Intra-operative photo

    Left retromastoid craniotomy with en bloc excision was performed. The cyst content was heterogenous, in which sebaceous content intermingled with hairs and fibrous tissue were found.

     
    Area of Interest: Neuroradiology brain; Imaging Technique: Gamma knife; Procedure: Intraoperative; Special Focus: Cysts;
     
     
  • Figure 9
    Histopathology

    The lesion histology reviewed irregular islands of atypical squamous cells, with hyperchromatic and pleomorphic nuclei, prominent nucleoli and rare mitosis, with invasion into the adjacent cerebellar tissue in small...

     
    Area of Interest: Neuroradiology brain; Imaging Technique: Gamma knife; Procedure: Intraoperative; Special Focus: Cysts;
     
     
CT brain with left posterior cranial fossa mass. A space occupying lesion with intra-lesional calcification and macroscopic fat, mainly extra-axial but its interface with the left cerebellar hemisphere was indistinct.
 
A tiny fat component was seen along the left tentorium. It could be related to rupture of the cyst contents.
 
T1W shows intralesional hyperintensity, corresponding to the known lipomatous component. The lesion was mainly extra-axial with suspicious component of intra-axial invasion, favouring an aggressive lesion.
 
Tiny T1W hyperintense deposit was noted along the left tentorium, corresponding to the macroscopic fat in CT scan
 
T2W shows intralesional cystic component. Peri-lesional edema with mass effect onto the fourth ventricle was demonstrated.
 
DWI reveals typical restricted diffusion for dermoid cyst.
 
There is heterogeneous intra-lesional gadolinium enhancement. No leptomeningeal enhancement was demonstrated.
 
Left retromastoid craniotomy with en bloc excision was performed. The cyst content was heterogenous, in which sebaceous content intermingled with hairs and fibrous tissue were found.
 
The lesion histology reviewed irregular islands of atypical squamous cells, with hyperchromatic and pleomorphic nuclei, prominent nucleoli and rare mitosis, with invasion into the adjacent cerebellar tissue in small irregular islands.
 
 
 
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