Presentation
A young male presented with abnormal behavior, sleep disturbance, and severe polydipsia. Clinical and laboratory investigations established a diagnosis of diabetes insipidus. No previous history of malignancy or surgery.
Patient Data
MR reveals a well-defined oval-shaped suprasellar-hypothalamic lesion at the midline which is isointense to cortical grey matter on non-contrast T1WI and slightly hyperintense on T2WI. No diffusion restriction was noted and lesion shows diffuse homogenous enhancement after contrast administration. There is a mass effect upon the optic chiasm and bilateral, symmetrical perilesional vasogenic edema.
Findings are most suggestive of suprasellar germinoma. Differential diagnoses included hypothalamic glioma and lymphoma.
Serum chorionic gonadotrophin and anti-α-fetoprotein were negative.
The patient underwent open frontotemporal biopsy.:
Histology
Biopsy specimens showed inflammatory infiltrates, which were composed mainly of lymphocytes and plasma cells. No granulomas and malignant cells were found.
Diagnosis: Encephalitis (hypothalamitis).
After a one-month low dose steroid treatment, the patient's symptoms improved and follow up MRI was performed.
Follow up MRI demonstrates the near-complete regression of the suprasellar-hypothalamic lesion. There are only infundibular thickening and faint hypothalamic enhancement present after contrast administration.
There are also few small enhancing nodular lesions on bilateral frontal and right anterior temporal lobes, possibly post-op changes.
Case Discussion
There are few published articles and case reports in the literature related to hypothalamic inflammation and regression after steroid treatment. This case reaffirms the steroid responsiveness of mass-like hypothalamitis.
We would like to emphasize that radiologists should keep in mind inflammatory lesions in the differential diagnosis of the hypothalamic region mass-like lesions. Actually, this case was initially reported as a suprasellar germinoma.
On the other hand, there are also published cases on literature that show suprasellar germinoma also could be responsive to steroid treatment.
Special thanks for supporting this case to neurosurgeon Dr. Alesker Hasratov, from Republican Neurosurgery Hospital (Baku, Azerbaijan).
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