Imaging of the pituitary and sella turcica

Pituitary hyperplasia due to Himalayan endemic hypothyroidism

Pituitary hyperplasia due to hypothyroidism can be treated medically. This condition should not be mistaken for adenoma and surgery should be avoided.

Primary hypothyroidism in a child leads to pituitary hyperplasia: A case report and literature review

RATIONALE

A sellar mass in children is most often seen in craniopharyngeal tumors, intracranial germ cell tumors, or pituitary adenomas. However, pituitary hyperplasia secondary to primary hypothyroidism (PHPH) is not commonly seen in children.

PATIENT CONCERNS

A 10-year-old girl was admitted due to growth retardation and obesity for 4 years. On physical examination, the patient had a height of 118 cm, body weight of 46 kg, body mass index (BMI) of 33.0 kg/m.

DIAGNOSES

After magnetic resonance imaging (MRI) and laboratory tests, her initial diagnosis was Hashimoto's thyroiditis, primary hypothyroidism, and reactive pituitary hyperplasia.

INTERVENTIONS

She was treated with oral L-thyroxine tablets.

OUTCOMES

After 6 months, physical examination showed a height of 125 cm, weight of 36 kg, BMI of 23.0 kg/m. She developed well, with 12 cm of yearly growth thereafter.

LESSONS

The diagnosis of PHPH in a child is very important and sometimes difficult. Based on the summary and analysis of previous cases, we can learn that the main manifestations of PHPH include growth arrest and obesity, perhaps accompanied by symptoms caused by a decreased thyroid hormone concentration and elevated prolactin (PRL) concentration. Intracranial MRI shows diffuse enlargement of the anterior lobe of the pituitary gland, with a dome-shaped blunt edge change. Thyroid hormone levels may decrease, whereas the thyroid stimulating hormone (TSH) level increases, commonly accompanied by an elevated PRL, reduced growth hormone (GH) levels, and positive findings of TPOAb and TGAb. Improvement of symptoms and the normalization of hormone levels as well as restoration of pituitary size can be achieved after treated with thyroid hormone replacement therapy. And a hasty decision on surgical resection should be avoided when the diagnosis is uncertain.

Morphometric Analysis of Sella Turcica Using Cone Beam Computed Tomography

OBJECTIVE

The purpose of this study was to assess morphological shape and morphometric analysis of the sella turcica using cone beam computed tomography (CBCT) in different planes of section (coronal and sagittal).

MATERIALS AND METHODS

CBCT images of 177 subjects of which 51 males and 126 females in the age group of 11 to 73 years were included in the study population. Linear dimensions which include the length, depth, diameter, and interclinoid distance were measured and the shape of sella turcica was analyzed.

RESULTS

Sella turcica had circular morphology in 69.5% of the subjects while flattened shape of sella turcica was observed in 16.4%, oval shape of sella turcica in 14%. There was no significant difference in the all measurements of sella turcica between males and females (P > 0.05). Diameter (P < 0.01), depth (P < 0.001), length (P < 0.05), and interclinoid distance (P < 0.05) of the sella turcica differed significantly with age.

CONCLUSIONS

The anatomical structure of sella turcica can be studied effectively in CBCT images. Linear dimensions and shape of sella turcica in the current study can be used as reference standards for further investigations.

Clinical significance of MRI-aided measurements in the transsphenoidal approach in Chinese adults

To determine the optimal direction for approaching sellar tumors, we developed an anatomical model of the most common approach, the transsphenoidal approach, in Chinese adults by analyzing MRI-aided measurements. Craniocerebral MRI of 75 Chinese adults with pituitary tumors and 238 healthy Chinese adults were obtained to analyse the angle between the direction of the transsphenoidal approach and the reference line linking the glabella and the external occipital tubercle, the approach depth, and the distance between the internal carotid arteries (ICA) at the cavernous sinuses segment. The mean angle (± standard deviation [SD]) between the direction of the transsphenoidal approach and the reference line in patients with sellar tumors was 40.51 ± 2.98°, similar to the angle in the healthy control group (41.18 ± 3.35°) (p > 0.05). The mean depth (± SD) calculated via the transsphenoidal approach in the sellar tumor group was 86.01 ± 4.99 mm, which was similar to the control group (85.34 ± 4.96 mm) (p > 0.05). However, the mean distance (± SD) between the bilateral ICA at the cavernous sinuses in the patients with sellar tumors was 22.68 ± 5.03 mm, greater than in the control group (15.89 ± 3.11 mm) (p < 0.01). Thus, during sellar tumor resection via the transsphenoidal approach, the patient's head should be first positioned to allow the line linking the glabella and the external occipital tubercle to be perpendicular to the horizontal plane, and then inclined backwards at an angle of about 40°. The floor of the sella, at a depth of about 85 mm, can then be reached vertically by introducing a speculum via a single nostril. The operative field should be limited to about 1cm from the midline. By adopting this method, the optimal angle and depth of the transsphenoidal approach can be determined without complicated equipment. Moreover, this technique is simple and accurate enough to maintain the correct approach, locate the lesion, and reduce the incidence of serious postoperative complications, including bleeding caused by rupture of the ICA.

[Sellar tumors]

Because of the complex anatomy, examination of the sella turcica and hypophysis needs a dedicated MR sequence protocol. Not every sellar lesion is a pituitary adenoma. Thus, this review article summarizes the most frequently encountered intra-, supra-, and parasellar tumors and lesions. Differential diagnoses comprise besides adenoma among others craniopharyngioma, meningioma, glioma, germinoma, hamartoma, aneurysm, trigeminal schwannoma, pituitary carcinoma, chordoma, metastasis, infection, and empty sella. Characteristic imaging findings are presented and correlated to micro- and macro-pathology.