T1 post-gad T2 FSE FIR

Diagnosis: Glial hamartoma

Glial hamartoma consists of normal glial cells located in an abnormal position. In one large series of 116 resections of cortex for epilepsy, 10 glial hamartomas were found. Of these, the cells were astrocytic in 3, oligodendrocytic in 6, and mixed oligoastro in 1. If a patient presents with a lesion that is found to be hamartomatous but does not have the stigmata of tuberous sclerosis the lesion is labeled as a hamartoma rather than a tuber. Although hamartomas may appear anywhere, they are more commonly located in the gray matter. In this case; however, the lesion was located entirely within the white matter and consisted primarily of oligodendrocyte cells. There was no atypia.

In general, other things to consider in the differential diagnosis of cortically based masses in the temporal lobe include tubers or hamartomas, focal cortical dysplasia, oligodendroglioma, DNET, and ganglioglioma. The appearance of this lesion; however is not good for ganglioglioma since they tend to be more cystic in appearance and often demonstrate enhancement. This patient was otherwise healthy and had no signs of tuberous sclerosis. Related Cases

Heniz ER, Crain BJ, Radtke RA, Burger PC, Friedman AH, Djang WT, Wilkinson WE. MR imaging in patients with temporal lobe seizures: correlation of results with pathologic findings. AJR, Sep 1990; 155(3):p581-6.

Vital A, Marchal C. Loiseau H, Rougier A, Pedespan HM, Rivel J, Vital C. Glial and neuronoglial malformative lesions associated with medically intractable epilepsy. Acta Neuropathol, 1994; 87(2):p196-201.

Ganglioglioma Tuberous sclerosis DNET