Endocrine Abstracts

Objective: Despite a wide variety of differential diagnosis, modern MRI imaging usually enables a good preoperative evaluation of the aetiology in most cases with scull base and sellar lesions. However, in some cases MRI visualization alone may also be misleading with a consecutive need to adapt intraoperative strategies.

Clinical presentation: The case of a 67-year-old male patient with the history of a bacterial meningitis, visual deterioration and the onset of diabetes mellitus is presented. MRI imaging demonstrated an intra- and suprasellar lesion of about 22 mm in diameter compressing the optic chiasm. The sella floor was enlarged. Visual acuity was 0.1 and 0.06 with concentrically narrowed visual fields. From a neuroendocrinological standpoint IGF-1 was elevated consisted with the diagnosis of a large GH-secreting macroadenoma and acromegaly.

Intervention and diagnosis: The lesion was operated by a transsphenoidal approach with typical pituitary adenoma tissue, although with a somehow inhomogeneous texture, found intraoperatively. However, the diaphragma sellae did not descent, despite the dominant suprasellar tumor parts on preoperative MRI imaging. Moreover, the diaphragma sellae was completely intact. Intraoperative high-field MRI imaging confirmed a large suprasellar tumor remnant with an already empty sellae beneath. Extending the transsphenoidal approach, a firm, partial calcified tumor originating from the diaphragma itself, was resected completely followed by an extensive reconstruction of the sellar floor.

Histopathologically the intrasellär parts of the lesion were composed of a sparsely granulated GH-secreting pituitary adenoma and a distinctly separated non-secreting adenoma with immunohistochemical expression of LH and FSH again anatomically separated by the diaphragma sellae from the suprasellar part of the lesion constituting a typical meningioma.

Conclusion: We present the rare coincidence of three immunohistochemically different and clearly separated scull base tumors with acromegaly mimicing a single intra- and suprasellar tumor on preoperative MRI imaging.