Teaching Case

A 28-year-old man with no medical history was admitted to our hospital referring a tonic and generalised seizure. He reported a headache in the past 4 years which worsened with exercise and physical effort.

Physical examination was normal.

Emergency head CT was performed.

CT scan showed an intra-axial heterogeneous mass of 4 cm in the right temporal lobe, with cystic (hypoattenuating) and soft-tissue (hyperdense) components and heterogeneous enhancement after intravenous contrast administration, identifying an enhancing solid mural nodule. There was no oedema or mass effect.

MR was performed and showed a heterogeneous mass in the right temporal lobe, predominantly cystic with a peripheral solid enhancing nodule, after intravenous contrast administration. No mass effect or vasogenic oedema was seen.

These findings were suggestive of pleomorphic xanthoastrocytoma, which was surgically resected and confirmed the diagnosis.

Pleomorphic xanthoastrocytoma is a benign supratentorial astrocytoma typically found in adolescents and young adults, with no gender predilection. It is a rare tumour that represents less than 1% of all astrocytomas. It is a hemispheric circumscribed and slow-growing mass, which involves cortex and meninges, and most frequently located in the temporal lobe, representing an important cause of temporal lobe epilepsy. [1, 2]

Pleomorphic xanthoastrocytoma´s origin is not clearly known; it may originate from cortical astrocytes or from multipotential neuroectodermal precursor cells. [1, 4]

The most common symptom is long-standing epilepsy, but it can produce headache and focal neurologic deficits. [1,3]

At microscopy, cellular pleomorphism, giant cells with lipid deposits (xanthomatous) and a dense reticulin network are seen. There is a low or absent mitotic activity and no necrosis. It is positive for glial fibrillary acidic protein (GFAP) due to the astrocytic origin. [2, 4]

CT shows a well-defined peripheral heterogeneous mass with a cystic hypoattenuating component and a solid mural nodule, which has an important enhancing after intravenous contrast. Furthermore, it may exhibit an enhancing dural tail and mild vasogenic oedema is uncommon. Haemorrhage is rare and calcifications may occur, but bone changes are not seen. [1, 2, 4]

MR imaging is the technique of choice. The cystic component has the same imaging characteristics as cerebrospinal fluid on all sequences. The solid component is isointense or hypointense to grey matter on T1-weighted images, hyperintense to grey matter on T2-weighted images and has a heterogeneous enhancement after intravenous gadolinium. No mass effect or restriction on DWI is shown.  [1, 3]

It is classified as a WHO grade II tumour, due to a higher recurrence and potential of malignant transformation, with a good prognosis and survival of 70% at 10 years. Malignant transformation occurs in 10-25% of cases. [1, 2, 3]

The treatment of choice is surgical resection, which may be curative. Chemotherapy and radiotherapy show no response. [1, 2]

In conclusion, pleomorphic xanthoastrocytoma should be suspected in a young adult patient with long seizure history and a cystic supratentorial mass with a mural nodule on imaging findings. [1, 2]