In familial cases of
combined pituitary hormone deficiency the most common mutations are that of Prophet of Pit 1 (PROP1) gene. PROP1 mutations are associated with deficiencies of
growth hormone,
thyrotropin,
prolactin, and
gonadotropins (
follicle-stimulating hormone and
luteinizing hormone), with evolving
adrenocorticotropin (
ACTH) deficiency in some cases. On imaging in most patients the pituitary gland is hypoplastic, but occasionally transient pituitary enlargement is found. We report a 22-year-old female initially diagnosed at age 12 with familial
hypopituitarism due to PROP1 mutation, who presented with
coma and respiratory arrest (acute
hyponatremia). She was urgently treated in Intensive Care Unit of Emergency Center with hypertonic saline and stress doses of
hydrocortisone, which resulted in the fast increase of plasma osmolality resulting in the osmotic
demyelination syndrome. Simultaneously and incidentally on computed tomography scan a large sellar and suprasellar mass were reported as possible
Rathke's cleft cyst or
craniopharyngioma. Once the patient was stable,
ACTH deficiency was documented. She remained replaced with
hydrocortisone and subsequently underwent transphenoidal surgery. The removed sellar content revealed no
pituitary adenoma or pituitary cells, but only an eosinophilic,
colloid-like mass, and necrotic acellular debris. Her sister with
hypopituitarism had an empty sella. Genetic testing in both sisters revealed the same homozygous c.150delA mutation in PROP1 gene. Here we report two sisters with the same PROP1 mutation who presented in adulthood with different pituitary morphology, one of them with a large sellar and suprasellar mass, in which transphenoidal surgery provided an extremely rare opportunity for a histopathological analysis of the sellar content. Due to the lack of endocrine care during the transition period hypocortisolism which evolved, a consequence of PROP1 mutation, was not recognized. Empirical use of
hydrocortisone in the
Intensive Care in our patient with life-threatening acute
hyponatremia was appropriate but because
glucocorticoid therapy on its own corrects
hyponatremia even after stopping hypertonic saline infusion, the risk for over-correction of
hyponatremia in
ACTH deficiency is high.