Neuroimaging characteristics and growth pattern on magnetic resonance imaging in a 52-year-old man presenting with pituicytoma: a case report

Abstract

Introduction: Pituicytoma is a rare neoplasm of the neurohypophysis. To the best of our knowledge there have been no reports of pituicytoma in which long-term magnetic resonance imaging observation was performed. We calculated the doubling time of the tumor volume and described the growth pattern of a pituicytoma.

Case presentation: A 52-year-old Japanese man with a history of decreased libido was found to have a sellar and suprasellar mass. He underwent transsphenoidal surgery, but only a small specimen was obtained because of intraoperative bleeding. The tentative histological diagnosis was schwannoma. He noticed bitemporal hemianopsia 7 years later. A follow-up magnetic resonance imaging disclosed a tumor volume doubling time of 3830 days. Transcranial gross-total tumor resection was performed. The lesion consisted of elongated and plump tumor cells that were arranged in a fascicular or storiform pattern and were positive for S-100 protein and focally positive for glial fibrillary acidic protein. The final histological diagnosis was pituicytoma.

Conclusion: Pituicytoma is a slow-growing tumor, but the growth rate may change during follow-up.

Figure 1

Initial magnetic resonance imaging. A) T1-weighted magnetic resonance image showing an isointense pituitary mass. B) T2-weighted magnetic resonance image showing a hyperintense mass.

Figure 2

Magnetic resonance imaging at 7 years after initial surgery. A–C) Axial, coronal and sagittal contrast-enhanced magnetic resonance image showing enlargement of the tumor.

Figure 3

Microscopic findings. A) Microphotograph of an hematoxylin and eosin-stained section showing bipolar spindle cells arranged in a storiform pattern. B) S-100 immunohistochemical stain. C,D) Immunohistochemical stains were focally positive for glial fibrillary acidic protein and positive for vimentin.

Figure 4

A semi-logarithmic graph showing serial changes of the tumor volume. The tumor volume doubling time (TVDT) was 3830 days during the follow-up period of 7 years, with TVDTs of 20267 days over the first 5 years and 1369 days over the last 2 years.