Endocrine Abstracts

Background: While pituitary adenomas are the commonest Sella neoplasm, number of other entities should be considered in the differential diagnosis and the diagnosis is based on histopathological and immunohistochemical characteristics. Pituitary tumors with papillary architecture are uncommon and have limited differential diagnoses. Primary papillary epithelial tumor of the pituitary is a recently described histopathological entity with striking papillary architecture and TTF1 positivity.

Case: A 60-year-old male presented with a 1-year history of gradual visual deterioration, mild hypothyroid symptoms and erectile dysfunction without any constitutional symptoms, systemic symptoms and features of diabetes insipidus. A pituitary adenoma was suspected and imaging revealed 2.8*2.4*2.5 cm solid mass involving pituitary fossa and suprasellar region causing displacement of the optic chiasm. Endocrine evaluation revealed evidence of central hypothyroidism and hypogonadism. The patient had undergone transcranial surgery and histological evaluation revealed a neoplasm predominantly composed of papillary structures without any aggressive features. Immunohistochemistry revealed positive staining for Cytokeratin 7, Pan-Cytokeratin, and occasional expression of TTF1 with Ki 67 index of 1%. Extensive evaluation for the possibility of metastatic deposit from papillary adenocarcinoma was negative. After excluding other causes for similar histopathological appearance, the lesion was diagnosed as a primary papillary epithelial tumor of the Sella. The patient was offered radiotherapy following the surgery and had a residual tumor on imaging at 3 months. Re-evaluation at 1 year revealed no interval change of residual lesion and the patient was well.

Conclusions: Primary papillary epithelial tumor of the Sella is a novel described histopathological entity. It needs to be considered in the differential diagnosis of Sella tumors with papillary architecture after excluding other causes for similar histopathological appearance including extensive evaluation for a possibility of metastatic deposit. Prognosis seems to be favorable, however, long term follow-up studies are required to assess the behavior and the best therapeutic option.