Teaching NeuroImages: Ectopic posterior pituitary

Magnetic resonance imaging characteristics of residual pituitary tissues following transsphenoidal resection of pituitary macroadenomas

Objective

The present study is to investigate the pre- and post-operative magnetic resonance imaging of pituitary tissues following transsphenoidal resection of pituitary macroadenomas, as well as its clinical significance.

Materials and Methods

The medical records of 108 consecutive pituitary macroadenoma patients admitted at Fuzhou 900th Hospital between September 2012 and September 2014 were retrospectively reviewed. Siemens 3. 0T magnetic resonance scanner was used to perform pre- and postoperative MRI scanning, including plain scan and contrast-enhanced scan of SE sequential T1WI and T2WI in sagittal, coronal and axial views. PACS medical imaging system was used to measure the diameter of pituitary adenoma, as well as the volumes of the adenoma and pituitary tissue. Hematoxylin-eosin staining and immunohistochemical staining were also performed.

Results

Higher height of pituitary adenoma results in lower rate of posterior pituitary bright spot (PPBS) on MR T1-weighted imaging. Preoperative MR signal intensity of PPBS was negatively related to diabetes insipidus (DI). Normal pituitary tissues were likely to be above the pituitary adenomas in growth hormone-secreting adenoma patients, while mostly located aside in gonadotropin-secreting adenoma patients. Morphological restitution of postoperative pituitary tissues was better in lateral displacement than that in superior or superolateral patterns on pre-operative MR images. Positive rate of PPBS on preoperative MRI is negatively related to adenoma height, and the signal intensity of PPBS is inversely related to postoperative DI.

Conclusions

The relative locations of pituitary tissues and adenoma tissues may be associated with the adenoma type and may affect the postoperative remodeling of residual pituitary tissues.

Anterior Gray Matter Pituicytic Heterotopia with Monomorphic Anterior Pituitary Cells: A Variant of Nonsecretory Pituitary Adenoma Neuronal Choristoma? Report of a Rare Case and Review of the Literature

BACKGROUND

Mixed tumors of adenomatous and neuronal cells in the sellar region are an uncommon finding. The origins of these heterogeneous tumors are unknown, and management remains unsettled. We report a very rare case of anterior gray matter pituicytic heterotopia with monomorphic anterior pituitary cells that likely represents a variant of nonsecreting pituitary adenoma neuronal choristoma (PANCH) with no ganglion cells. We also review the current literature for the various clinical presentations of PANCH.

CASE DESCRIPTION

A 49-year-old female complaining of headache, blurred vision, and hair loss was found to have a nonsecretory sellar mass with compression of the optic chiasm on magnetic resonance imaging (MRI). The mass was excised via a transsphenoidal procedure. Histological analysis of tissue sections revealed heterotopic gray matter with reactive gliosis without ganglion cells or Herring bodies. Only 1 smear exhibited characteristics of a pituitary adenoma.

CONCLUSIONS

The overall findings were most consistent with a variant of PANCH. At a postoperative follow-up of 4.5 years, there was resolution of visual symptoms, and the residual sellar mass was stable on MRI. Neuronal choristoma is hypothesized to originate from embryonal pituitary or hypothalamus, or by differentiation from pituitary adenoma cells. Surgery is the cornerstone of management, and the clinical course appears to be similar to that of nonfunctioning pituitary adenoma in reported cases.

Relationship between pituitary stalk (PS) visibility and the severity of hormone deficiencies: PS interruption syndrome revisited

CONTEXT

Pituitary stalk interruption syndrome (PSIS) is a rare cause of combined pituitary hormone deficiency characterized by a triad shown in pituitary imaging, yet it has never been evaluated due to the visibility of pituitary stalk (PS) in imaging findings.

OBJECTIVE

The major objective of the study was to systematically describe the disease including clinical presentations, imaging findings and to estimate the severity of anterior pituitary hormone deficiency based on the visibility of the PS.

METHODS

This was a retrospective study including 74 adult patients with PSIS in Shanghai Clinical Center for Endocrine and Metabolic Diseases between January 2010 and June 2014. Sixty had invisible PS according to the findings on MRI, while the rest had a thin or intersected PS. Basic characteristics and hormonal status were compared.

RESULTS

Of the 74 patients with PSIS, age at diagnosis was 25 (22-28) years. Absent pubertal development (97·3%) was the most common presenting symptom, followed by short stature. Insulin tolerance test (ITT) and gonadotrophin-releasing hormone (GnRH) stimulation test were used to evaluate the function of anterior pituitary. The prevalence of isolated deficiency in growth hormone (GH), gonadotrophins, corticotrophin and thyrotrophin were 100%, 97·2%, 88·2% and 70·3%, respectively. Although the ratio of each deficiency did not vary between patients with invisible PS and with visible PS, panhypopituitarism occurred significantly more frequent in patients with invisible PS. Patients with invisible PS had significantly lower levels of luteinizing hormone (LH), follicle stimulation hormone (FSH) and hormones from targeted glands including morning cortisol, 24-h urine free cortisol, free triiodothyronine (FT3), free thyroxine (FT4) and testosterone (T) in male than patients with visible PS. Moreover, patients with invisible PS had lower peak LH and FSH in GnRH stimulation test, and higher peak cortisol in ITT while peak GH remained unchanged between two groups.

CONCLUSIONS

The prevalence of multiple anterior pituitary hormone deficiency was high in adult patients with PSIS. And more importantly, we found the visibility of PS shown on MRI might be an indication of the severity of PSIS.