Pituitary stalk interruption syndrome presenting as short stature: a case report

Abstract

IntroductionPituitary stalk interruption syndrome is a rare congenital abnormality of the pituitary that is responsible for anterior pituitary deficiency. It is characterized by a classic triad of interrupted pituitary stalk, absent or ectopic posterior pituitary, and anterior pituitary hypoplasia or aplasia. Clinical presentation varies according to age. In adults it presents as short stature and anterior pituitary deficiency. Without early diagnosis and treatment, mortality and morbidity in these patients is high. Early diagnosis and treatment of this rare disease can prevent permanent short statue of the patient. We report the first case of pituitary stalk interruption syndrome from Pakistan.Case presentationA 17-year-old Pakistani young man presented with short stature and underdeveloped secondary sexual characters. His siblings and parents were healthy, with normal height. An examination showed his blood pressure was 90/60mmHg, and his height, weight, and body mass index were 142cm, 34.5kg, and 17.10kg/m2, respectively. He had no hair growth on his face, axilla, or pubis. His testes were between 1 and 2mL in size, with a 4cm-at-stretch micropenis. His lab investigations showed that his thyroid stimulating hormone (TSH) was 8.58uIU/mL (0.4 to 4.2), his free thyroid hormone level FT4 was 0.46ng/dL (0.89 to 1.76), his prolactin was 21.1ng/mL (3.0 to 14.7), and his baseline cortisol was 0.30ug/dL (4.3 to 22.4). His cortisol level after 60 minutes of cosyntropin injection was 3.5ug/dL (4.3 to 22.4), his insulin like growth factor IGF-1 was 31.56ng/mL (247.3 to 481.7), his testosterone level was under 2.5ng/dL (2 to 800), his follicle stimulating hormone FSH was 0.41uIU/mL (0.0 to 10.0), and his leutinizing hormone LH was under 0.1uIU/mL (1.2 to 7.8). His bone age was 10 years according to the Greulich and Pyle method, as shown by X-rays. The results from his pituitary magnetic resonance imaging scan were consistent with pituitary stalk interruption syndrome.ConclusionsWe describe a young man who presented with short stature and was found to have pituitary stalk interruption syndrome. Despite the fact that this is a rare disorder, it should always be kept in the differential diagnosis of a patient presenting with short stature. Patients with this disease have an excellent opportunity to reach normal height if they present before the joining of epiphyses.

Pituitary Stalk Interruption Syndrome

“…Cases have been described with isolated sparing of TSH secretion with a deficiency of the remaining anterior pituitary hormones [4]. Our patient's thyroid function tests favored secondary hypothyroidism because of a very low free T4 (FT4) level and slightly increased TSH level, together with a negative anti-thyroid antibody level; Similar findings were also reported by Guo et al in a subgroup of PSIS patients [5]. Interestingly, patients initially presenting with isolated GH deficiency initially, may develop multiple anterior pituitary hormone deficiencies later in life in the second or third decade of life [1].…”

“…Interestingly, male predominance has also been reported with a male-to-female ratio of 2.3-6.9:1.0, suggesting X-linked inheritance [1]. The incidence of breech delivery, cesarean section, and neonatal distress are high in the PSIS population [5]. Breech delivery leads to deformation of the head which can result in injury to the pituitary stalk.…”

“…Breech delivery leads to deformation of the head which can result in injury to the pituitary stalk. Similarly, hypoxemia due to anoxia after birth may also cause injury of the pituitary stalk and pituitary [5]. Genetic mutations are thought to contribute to less than 5% of PSIS cases.…”

Pituitary stalk interruption syndrome presenting in a euthyroid adult with short stature

“…MRI findings of PSIS sums a typical triad of absent pituitary stalk, absence of adenohypophysis, and an ectopic posterior pituitary all found in our case as well. Variations on MRI findings can also be found, which may include location of the posterior pituitary gland (behind optic chiasma in our case), hypoplastic to absent adenohypophysis, or stalk variations (thin, normal, or absent) [5] , [13] , [14] . Multiple anterior pituitary hormone deficiency is often noticed in patients with PSIS, but visualization of the pituitary stalk on MRI is associated with isolated deficiency of growth hormone [13] , [14] .…”

“…Secondly, tertiary hypothyroidism was not a characteristic of our case as it is, in previously reported cases in the literature. Lastly, only 1 case is reported in the literature from Pakistan to the best of our knowledge to date [5] .…”