Endocrine Abstracts

Introduction

Pituitary gland tumors constitute approximately 10–15% of primary brain tumors, and posterior pituitary tumors are extremely rare. Granular cell tumor (GCT) is a low grade non-neuroendocrine neoplasm. Here, we will present our case who was found to have GCT during follow-up of diabetes insipidus (DI).

Case

A 23-year-old male patient applied to our outpatient clinic for routine control. 12 years ago, he was diagnosed with growth hormone deficiency and central hypothyroidism during tests performed for short stature, and used growth hormone and levothyroxine treatments, and it was learned that these treatments were discontinued after puberty, and he had been using desmopressin for partial DI for 10 years. He was using desmopressin 240 mg/day at presentation. His height and weight were 165 cm and 60 kg, his blood pressure was 120/80 mm Hg, and his pulse was 72 beats/min. Systemic examination was normal. Serum Na level was 142 mEq/l, serum osmolality was 291 mOsm/kg, spot urine osmolality was 693 mOsm/kg, and urine density was 1020 (Table 1). On the neurohypophysis lodge, a high-signal lesion area (granular cell tumor?) was observed with magnetic resonance imaging in T1A and T2A series with 1.4 × 1 × 0.6 cm dimensions, which created convexity at the base of the sella contour. When the pituitary images of previous years were examined, it was reported that neurohypophysis was normal in 2010 and 2016, tubular structure showing loss of signal in all sequences in the neurohypophysis (vascular structure?) was observed in 2013, and in 2019, it was determined that a lesion (lipoma?, terotoma?, dermoid cyst?) was detected in the neurohypophysis lodge, which showed suppression (?) in a fat-suppressed sequence of 13 × 7 mm in size, and did not form a distinct opacification pattern in dynamic study. He was evaluated in a multidisciplinary council and follow-up was planned.

Discussion

DI was seen in 3–5% of GCT cases. In our case, no tumor was observed on neurohypophysis at the time of diagnosis, but GHT was detected during follow-up. We are of the opinion that periodic pituitary imaging in DI cases may increase the possibility of detecting rare tumors such as GHT.