Endocrine Abstracts

Introduction: Pituitary tumors can be classified according to their endocrine function, starting from the clinical phenotype to establish a diagnosis. The histological analysis can confirm the clinical suspicion. A thorough classification is essential in the therapeutic approach with an important influence in the disease-free survival.

Case report: We report a case of a 16-year-old male, with loss of visual acuity and headache, attended by an Ophthalmologist in May/1993 who detected papilloedema and suggested a CT that showed a sellar tumor with 4×2.8 cm. He was subjected to surgery in December/1993. Histological diagnosis was ‘non-functioning pituitary tumor’.

The post-surgical evaluation showed delayed puberty (TannerP1G1) and bitemporal hemianopsy. Laboratory findings: deficit in the thyroid, gonadal, adrenal axis and diabetes insipidus, with normal GH, IGF1 and prolactin. MRI showed ‘intra and infrasellar tumor residue’. He was started on substitution therapy.

Beginning in late 1995, prolactin progressively rose to 152 ng/ml (n<18 ng/ml), whereby in 1996 the patient was started on bromocriptine 2.5 mg, b.i.d. In 2000 was detected GH=7.0 mUI/l (n<4 mUI/l) with IGF1=377 ng/ml (n=182–780 ng/ml), a 15 cm stature growth, without acromegaly symptoms or dysmorphism. Revision of the histological analysis: ‘Prolactin secreting pituitary tumor’.

Persistently high random GH=5.09 ng/ml (n<4 ng/ml) and the elevation of IGF1=502 ng/ml (n=117–319 ng/ml), motivated the initiation of somatostatin analogues in 2005. There was a favorable laboratorial response: GH=3.41 ng/ml (n<4 ng/ml), IGF1=292 ng/ml (n=117–329 ng/ml) with reduction of the tumor residue dimensions.

At the present time, the patient has 34-years-old, a reasonable QoL under substitutive therapy, bromocriptine 10 mg, q.d., lanreotide 120 mg, every 6 weeks. The hormonal secretion is controlled: GH=1.3 μg/l (n<1.0 μg/l), IGF1=334 ng/ml (n=115–307 ng/ml), prolactin=10 ng/ml (n<18 ng/ml), but the latest MRI performed in 2012 showed a tumoral residue of similar dimensions. He was proposed for radiation therapy.

Conclusion: This case illustrates the difficulties in the characterization of some pituitary tumors (either clinical, functional and pathohistological classification), specially in younger patients. The appreciation of the hormone levels must be integrated, considering the pubertal staging and not only chronological age.