An 18 year old lady was seen in endocrine clinic in October 2004 with 10 month history of polyuria, polydypsia and lethargy. Previous medical history includes Graves thyrotoxicosis which is treated with carbimazole.
Clinical examination was unremarkable.
Investigations and management: Urine osmolality −84 mosmol (250750), serum osmolality −290 mosmol (288298), full blood count, fasting glucose, renal, liver function tests and serum calcium were normal. Water deprivation test confirmed central diabetes inspidus. Insulin stress test showed normal cortisol and suboptimal growth hormone response. TRH test showed exaggerated TSH response. GNRH test showed exaggerated LH and FSH response. Prolactin was normal.Magnetic Resonance Imaging of brain including pituitary was normal. She was started on Desmopressin nasal spray with significant improvement in her symptoms. She was regularly followed up in endocrine clinic (6 monthly intervals) with no further significant problems. She presented to Accident & Emergency department in October 2006 with 24 hour history of blurring of vision and 4 weeks of gradually worsening generalised headache.
Clinical examination revealed Glasgow coma scale of 15/15 with reduced visual acuity and bitemporal hemianopia on confrontation technique. Magnetic Resonance Imaging of brain including pituitary showed 3×2 cm mass along pituitary stalk with optic chiasm compression. Pituitary hormonal profile was normal. She underwent emergency decompression via trans-sphenoidal route followed by radiotherapy after few weeks. Histology confirmed Germinoma. Cerebro-spinal fluid analysis was normal with no evidence of seeding. Her vision improved significantly following surgical decompression and radiotherapy.
Discussion: Pituitary stalk tumors are relatively rare group of intracranial tumors and often very slow growing. Symptoms vary depending upon size, nature, position and local effects which are predominantly compressive in nature. Regular review and high degree of suspicion is often needed to diagnose at early stages.