PMC8013783_01
CT scan of hemorrhagic vermian EC. Native CT scan in axial plane (
a
) and sagittal plane (
b
) revealed a midline infratentorial hyperdense lesion causing compression of the fourth ventricle and brainstem. CT scan with bone setting (
c
) revealed a small, calcified spot (
white arrow
). CT, computed tomography; EC, epidermoid cyst.
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Obstructive hydrocephalus was present ( Fig. 1 ).
MRI of hemorrhagic vermian EC. MRI showed a lesion located in cerebellar vermis:hyperintense on T1-weighted images (
a
) and hypointense on T2-weighted images (
b
). On T1-weighted imaging with gadolinium in sagittal plane (
c
) the tumor did not show any contrast enhancement. EC, epidermoid cyst; MRI, magnetic resonance imaging.
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Due to tumorous expansion, syrinx of cervical spinal cord was present ( Fig. 2 ).
Intraoperative microscopic view of hemorrhagic vermian EC. Via midline suboccipital craniotomy we identified a dark cyst with a greenish mud-like debris. (
a,b
) The supposed calcified fragment (
white arrow
,
a
). During the procedure, a few pearl-like particles were found on the periphery of the lesion (
black asterisks
,
c
). During the procedure, a gross total resection was achieved.
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Dark cyst with a greenish mud-like debris content was identified ( Fig. 3 ), and the entire cyst wall with its content was completely removed.
Histological features of hemorrhagic EC. Microscopic examination revealed organizing blood clot (
a
, hematoxylin-eosin), and lightly basophilic keratin lamellae (
b
, hematoxylin-eosin), with dystrophic calcifications and heterotopic ossification (
c
, hematoxylin-eosin). Only few strips of benign squamous epithelium were found, with no adnexal structures (
d
, hematoxylin-eosin). The epithelium was immunohistochemically positive for squamous markers CK5/6 (
d
, inset) and P40. EC, epidermoid cyst.
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No dermal skin appendages, such as hair follicles or sebaceous glands were present ( Fig. 4 ).