Hypothalamic germinoma

Case contributed by Aruna Pallewatte
Diagnosis probable


Lethargy and ill health. Diagnosed on further investigations as panhypopituitarism.

Patient Data

Age: 50 years
Gender: Female

A well defined rounded lesion measuring 17mm(AP) x 18mm(T) x 10mm(CC) is noted in the hypothalamus. It is isointense on T1W and T2W images with avid contrast enhancement. There is no evidence of calcification or hemorrhage. No diffusion restriction. It abuts the mid brain posteriorly and compresses the infundibular recess of the third ventricle posteriorly. There is associated perilesional edema extending also into the optic chiasm and tracts which appear swollen. However, there is no compression of the optic chiasma or tract. Pituitary gland is normal in size with no focal masses. Sagittal images show the extension of the lesion to the infundibulum and tuber cinerum.  Pineal region appeared normal.

Case Discussion

The clinical presentation of hypopituitarism in this patient can be attributed to the extension of this lesion to involve the infundibulum and tuber cinerum. Alpha feto protein was elevated. Insidious manifestation of clinical symptoms are compatible with its indolent progression. The demographics of this patient such as being a relatively young female point towards the preferred diagnosis of germinoma rather than gliomatous lesions occurring in the hypothalamus - optic tract gliomas are more frequently encountered in young patients and are usually more diffuse.  Radiological features favoring the MRI diagnosis of a germinoma in this patient include isointensity with grey matter on non-contrast images and marked homogeneous well-circumscribed post contrast enhancement. This was also used to possibly exclude other lesions in the hypothalamic region such as hypothalamic gliomas which show heterogeneous enhancement and hamartomas which do not enhance.  

The patient declined biopsy and has been referred for radiotherapy. A brisk response is expected if the diagnosis is in fact germinoma. 

Case credit: By Dr Aruna Pallewatte, Dr Thanuja Pathirana


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