Pharyngeal pituitary non-functioning adenoma with normal intra-sellar gland: massive tumor shrinkage on octreotide therapy

Abstract

OBJECTIVE: Functioning or non-functioning ectopic tumors may develop from pharyngeal pituitary remnants. They constitute <1% of all obstructive pharyngeal masses and they have a strong tendency to bleed. We report a case of a non-functioning ectopic pituitary adenoma of the rhino-pharynx studied over a long-term somatostatin analog treatment. PATIENT AND TREATMENT: A 60-Year-old woman presented with severe posterior epistaxis. She had complained of nasal obstruction for the past 2 Years. Magnetic resonance imaging (MRI) and endoscopic examination revealed a 2 cm exophytic, bleeding mass in the cavum, which was judged inoperable, and a biopsy was performed. On immunostaining, tumor cells were positive for pancytokeratins MNF 116 and C11, epithelial membrane antigen, chromogranin and neuron-specific enolase (NSE), and negative for synaptophysin, desmin, actin, estrogen and progesterone receptors, all anterior pituitary hormones and human chorionic gonadotropin. Blood levels of the above hormones and tumor markers were normal, except for a moderate elevation of NSE (33.8 microg/l, normal value <12 microg/l). It was concluded that this was a non-functioning pituitary adenoma of the rhino-pharynx. MRI showed a normal intra-sellar pituitary gland, including the normal bright signal of the posterior lobe. Somatostatin receptor scintigraphy (SRS) disclosed intense tracer uptake in the tumor, indicating high somatostatin receptor content. There was also an intense uptake in the intra-sellar pituitary. Therapy with long-acting octreotide was started, 20 mg per Month i.m. RESULTS: The patient has been on octreotide for the last 12 Months. Nasal obstruction rapidly subsided and bleeding did not recur. Repeated endoscopic examinations showed rapid tumor reduction, the mass shrinkage being almost complete at 3 Months. This was confirmed by MRI, while SRS showed markedly decreased uptake in the residual tumor and the intra-sellar pituitary, and NSE became normal. CONCLUSION: Pharyngeal pituitary remnant adenomas are rare, but they must be considered in the differential diagnosis of bleeding or obstructive masses of the rhino-pharynx. In this case, the positive SRS influenced the choice of octreotide, as an alternative to surgery. As we show for the first time in this location, octreotide can exert prolonged and marked anti-tumoral effects in non-functioning adenoma.