Unusual mixed gangliocytoma-pituitary adenoma in sellar region

Abstract

Background The presence of ganglion cells within an endocrine pituitary adenoma in sellar region is rare, and is usually diagnosed as "mixed gangliocytoma-pituitary adenoma". Due to lack of radiological characteristics, it is very difficult to make an accurate diagnosis preoperatively. Herein we describe one case of unusual mixed gangliocytoma - growth hormone (GH) secreting pituitary adenoma in sellar region and review related literatures, so as to summarize the clinicopathological characteristics and improve the diagnosis and differential diagnosis of this tumor. Methods and Results A 28 - year - old female presented with headache and blurred vision for 8 months. She also complained of acromegaly and amenorrhea. Head CT and MRI examinations showed a sellar and suprasellar mass with clear boundary compressing the optic chiasm and buttom of the third ventricle. The mass exhibited isointense signal or mild hypointensity on T₁WI and mild hyperintensity on T₂WI with heterogeneous enhancement on the contrast MRI. The tumor was removed totally. The histological sections demonstrated two parts of intermixed areas. One part of areas was marked by a proliferation of scattered gangliocyte - like cells arranged in a fibrillary background. Other areas were marked by a sheet - like or locally papillary proliferation of round and oval cells. Immunohistochemically, cytoplasm of gangliocyte-cells were diffusely positive for synaptophysin (Syn), and negative for adenohypophysial hormones; cytoplasm of round and oval cells were diffusely positive for Syn, and almost 30% cells were positive for GH, and negative for other neurohypophysial hormones. A final diagnosis of mixed gangliocytoma-GH secreting pituitary adenoma in sellar region (WHO grade Ⅰ) was made. The patient did not receive postoperatively adjuvant therapy and was followed-up for one year, without any neurological deficit or signs of recurrence. Conclusions Mixed gangliocytoma - pituitary adenoma is extremely rare and a definite diagnosis should be made under microscopy examination. Since the histogenesis of this tumor suggests that the uncommitted stem/progenitor cells consist of both adenohypophysial and neuronal characteristics and are capable of giving rise to pituitary adenoma with neuronal component, a diagnostic term of "pituitary adenoma with ganglionic differentiation" is suggested for this independent entity rather than collision tumor combined by two separate tumors.

DOI: 10.3969/j.issn.1672-6731.2016.10.011