Endocrine Abstracts

JOINT1975

Introduction: Clinically nonfunctioning pituitary adenomas (NFPAs) include all pituitary adenomas that are not hormonally active. They account for 15-30% of pituitary adenomas, and are usually diagnosed by signs and symptoms related to a mass effect (headache, visual impairment, sometimes pituitary apoplexy), but also incidentally. In histopathology, somatotroph nonfunctional pituitary adenomas are considered rare, the majority of NFPAs are gonadotroph. They are associated to increased comorbidities, and reduced long-term survival.

Material and Methods: We report the case of a patient presenting NFPA which expressing anti-GH antibody. He is followed up in the Endocrinology, Diabetology and Metabolic diseases department of the Mohamed VI university hospital center in Marrakech.

Case presentation: A 56-year-old man, presented a tumoral syndrome made of decrease of visual acuity, and retroorbital headache. He had no particular medical history. He reported a decrease of the libido and erectile dysfunction evolving over the past 6 months. Laboratory workup revealed a normal insulin-like growth factor I (IGF1), 8 a.m. cortisol level, Thyroid-stimulating hormone (TSH) and prolactin, a gonadotropic deficiency FSH: 2,1 UI/l, LH: 0,6 UI/l Testosterone: 0.5. Pituitary MRI showed intra- and supra-sellar tumor process compressing the optic chiasm, suggesting in the first instance a pituitary adenoma measuring 45 x 33 mm. The ophthalmologic examination showed bilateral blindness. A transsphenoidal adenomectomy was performed in the neurosurgical department, and the anatomopathological and immunohistochemical study revealed a non-secreting pituitary adenoma expressing the anti-GH antibody. During follow up, biological tests showed in addition to the known gonadotropic deficiency, corticotropic and thyreotropic deficiencies were also present, which we substituted. The MRI imaging showed persistence of the sellar lesion process measuring 12 x 22 x 19 mm. Blindness persisted even after surgery. Radiotherapy treatment was indicated, but the patient refused it.

Conclusion: Somatotroph adenomas are usually accompanied by symptoms of acromegaly and an elevated plasma growth hormone (GH) and IGF-1 level. GH-immunopositivity occurs in a rare case of all tumor types of clinically non-functioning adenomas. Because of that, the diagnosis should be done by immunohistochemical techniques, which may provide information on tumor cell proliferation and biologic behavior.

Keywords: Non-functional pituitary adenomas, Gonadotroph adenoma, MRI, Adenomectomy, immunohistochemical techniques.