Posterior cranial fossa Mature cystic teratoma with extracranial stalk

Case contributed by Furqan Ahmad


Patient reported with a one-month history of severe headaches that were gradual in onset, throbbing in form with repeated episodes of non-projectile vomiting.

Patient Data

Age: 25 years
Gender: Male

Large well-defined, infratentorial, extra-axial lesion causing compression effect and anterior displacement of the cerebellum and causing obstructing hydrocephalus.

The lesion appears thick-walled with the hyperintense signal on T1-weighted images and a hypointense signal on T2-weighted images. An internal well-defined area at its dependent portion shows a T1 hypointense rim with signal dropout on SWI.

There is a stalk extension at the posterior aspect of the lesion which is extending through the occipital protuberance and is ending just beneath the skin causing its puckering.


Case Discussion

Posterior cranial fossa mature cystic teratoma, appears hyperdense on CT ( PACS images not available) which is likely secondary to saponification, microcalcifications, and blood products1.

The lesion, its stalk, and the portion of the skin attached to the stalk of the lesion were all completely removed during the patient's suboccipital craniotomy.

The lesion's final histology revealed that it was a mature teratoma without a malignant component. It consists of multiple light brown to pale yellow rubbery tissue pieces and had eosinophilic proteinaceous material with cholesterol cleft. Its wall consists of firm tissue pieces with nodular bony tissue. Microscopically cyst wall lined by stratified squamous epithelium with underlying skin appendages. 


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