Somatostatin-Producing Atypical Null Cell Adenoma Manifesting as Severe Hypopituitarism and Rapid Deterioration—Case Report

Abstract

Atypical adenoma has an aggressive biological character, invades the surrounding structures, and grows rapidly. Morphological malignant findings such as increasing cellularity and nuclear atypism are not involved in this entity, but some cases with overt malignant features such as significant nuclear atypism and/or necrosis are known. Null cell adenoma generally grows slowly, but hormone secretion is little understood. Atypical null cell adenoma is rare, and hormone production is unknown. A 55-year-old woman presented with severe hypopituitarism and diabetes insipidus and bilateral upper temporal quadrantanopsia. Head magnetic resonance imaging revealed a large sellar tumor compressing the optic chiasm. Transsphenoidal surgery was performed, but the tumor was partially removed because of invasion into the neuronal structures. Histological examination showed atypical null cell adenoma with significant nuclear atypism and extensive necrosis. Immunohistochemistry showed positive reaction to somatostatin. Adjuvant treatment was planned, but the tumor regrew within 3 months. Conventional irradiation resulted in slight decrease in tumor size, but she required assistance for every type of daily activity. Atypical null cell adenoma has an aggressive biological character, and immediate adjuvant treatment is essential. Somatostatin secretion was proven in this tumor type.

Giant Hemorrhagic Prolactinoma with Sparse Prolactin Expression Presenting with Thalamic Infarction—A Case Report

“…11,12 For instance, PRL serum levels higher than 200 ng/ml is often accepted as the specific cut-off value for prolactinoma, whereas this value is usually less than 100 ng/ml for the stalk effect caused by other types of parasellar tumors by preventing inhibitory control of dopamine secreted from hypothalamus. 9 An extreme increase in serum PRL concentrations suggests a prolactinoma.…”

“…Classic examples are the silent corticotroph and somatotroph adenomas, in which tumor cells stain positively for ACTH and GH, respectively, and yet patients have no clinical or biochemical features of excessive hormone secretion. 1,[6][7][8][9] Silent or nonfunctioning adenomas have no clinical expression of produced hormones, either because they produce inactive molecules or do not release sufficient amount of hormones from cells to create a detectable blood level. 4 Prolactinomas represent the majority of clinically recognized pituitary adenomas, accounting for approximately 40-45 % of all.…”

“…However, pituitary adenomas are known to present with hormone expression patterns incongruous with detectable serum hormone levels. Ogawa et al reported on a case of null cell adenomawith weak somatostatin expression and low serum hormone levels 9.…”

Clinicopathological Investigation of Vascular Endothelial Growth Factor and von Hippel–Lindau Gene-Related Protein Expression in Immunohistochemically Negative Pituitary Adenoma – Possible Involvement in Tumor Aggressiveness

“…Although our basic surgical strategy was to remove tumors as far as possible, evident invasion of the optic chiasm and third ventricle floor identified during the surgery limited intervention to probe resection in Case 25, who later developed pituitary carcinoma and died of pleuritis carcinomatosa (2). The follow-up period ranged from 3 to 190 months (mean 42.2 months).…”

“…Pituitary adenoma is generally known to be relatively indolent, but a few aggressive cases with local invasion and recurrence have been reported (1)(2)(3), including some cases of null cell adenoma (4,5). Many pathologists have tried to identify the underlying pathophysiological background for these unusual presentations, and a recent study indicated a relationship with overexpression of vascular endothelial growth factor (VEGF), a well-known key mediator of angiogenesis.…”