MRI of pituitary macroadenomas with reference to hormonal activity

A current perspective of pituitary adenoma MRI characteristics: a review

INTRODUCTION

MR imaging is an essential and fundamental tool in the diagnosis, management, and follow-up of patients with pituitary adenomas (PAs). Recent advances have continued to enhance the usefulness of this imaging modality.

AREAS COVERED

This article focuses on signal intensity patterns of PAs and associated clinical characteristics, vertical extension patterns, and cavernous sinus invasion with a special focus on the clinical implications that arise. A search using Medline and Google Scholar was conducted using different combinations of relevant keywords, giving preference to recent publications.

EXPERT OPINION

A higher proportion of GH-secreting PAs are hypointense on T2 weighted images compared to other tumor subtypes. Hypointense tumors are generally smaller compared to hyperintense ones, and among the GH-secreting subgroup, a better response to somatostatin analogue treatment was noted together with an association for a densely granulated pattern. Nonfunctional PAs show a predilection to extend upwards while GH-secreting PAs and prolactinomas show a predominantly inferior extension growth pattern. Further studies to better understand the mechanisms responsible for this behavior are anticipated. Further development, refining and validation of predictive scoring systems for tumor behavior might be useful adjuncts in the management of patients with PAs.

Quantitative Magnetic Resonance-Derived Biomarkers as Predictors of Function and Histotype in Adenohypophyseal Tumours

INTRODUCTION

Magnetic resonance imaging (MRI) is the main modality to diagnose adenohypophyseal tumours, while biochemical assessment of pituitary hormones allows for their functional classification. In this retrospective exploratory cohort study, we investigated if quantitative differences in tumour MR signal intensity (SI) could be utilized to predict the function and histotype.

METHODS

Clinically acquired pretreatment MRI images were retrospectively analysed in 67 clinically non-functioning gonadotropinomas (NFG), 38 somatotropinomas, and 16 medically treated giant macroprolactinomas. Mean T1- and T2-weighted SI values were determined for each tumour and normalized against either centrum semiovale white matter or CSF to derive relative T1W and T2W SI values and the relative tumour T2/T1 SI ratio. Inter-group differences in quantitative MR parameters were compared, and the power of each parameter to discriminate tumour type and subtype was assessed using the area under the receiver operator characteristic curve (AUROC). In resected somatotropinomas, the relationship between tumour granulation status, relative MR SI values, and biochemical data was also compared.

RESULTS

Compared to somatotropinomas, NFG and macroprolactinomas displayed higher relative T2W SI (p < 0.001) and higher relative tumour T2/T1 SI ratio values (p < 0.001, ANOVA). Compared to intermediate/densely granulated tumours, sparsely granulated somatotropinomas were larger (p = 0.006, Mann-Whitney U test), had higher relative T2W SI (p ≤ 0.005), and higher relative tumour T2/T1 SI ratios (p ≤ 0.001, 2-tailed t test). Relative tumour T2W SI values and relative tumour T2/T1 ratio values demonstrated good discriminatory power in differentiating NFG from somatotropinoma (AUROC = 0.87-0.94) and predicting somatotropinoma subtypes (AUROC = 0.87-0.95).

CONCLUSION

Quantitative SI-based MR parameters derived using clinical acquisition MRI protocols may help non-invasively discriminate the functional status of adenohypophyseal tumours and the histological subtype of somatotropinomas.

Imaging of Sella and Parasellar Region

The sellar and parasellar region is complex, with a unique meningeal, neural, vascular, and bony anatomy. Understanding the imaging anatomy is critical for accurate imaging interpretation. resonance (MR) imaging is the primary modality for pituitary imaging, whereas computed tomography may be used when MR imaging is contraindicated, and provides complementary bony anatomic information. This article reviews embryology and anatomy of the sellar and parasellar region. Imaging appearances of pituitary adenomas, Rathke cleft cysts, meningiomas, craniopharyngiomas, arachnoid cysts, vascular disorders, infectious abnormalities, and pituitary apoplexy are discussed and illustrated.

Patterns of extrasellar invasive growth of pituitary adenomas with normal sellar cavity size

BACKGROUND

Pituitary adenomas (PAs) are among the most common brain tumors which characteristically become symptomatic due to the mass effect on surrounding structures and/or hormonal imbalances. This study describes 28 cases of PAs with an extrasellar invasive growth (EIG) at the early stage of tumor growth with normal sellar cavity size.

METHODS

1200 cases of PAs either treated medically or via Endoscopic transsphenoidal surgery were reviewed during a 10-year period. Pre-operative imaging was analyzed to evaluate the tumor expansion pattern, tumor invasion sites and other relevant tumor properties. A comprehensive preoperative endocrinological along with postoperative histopathological studies were conducted to evaluate the subjects' homeostasis and further identify the lesions characteristics.

RESULTS

Of the 28 patients, patients 19, 2, 1 and 6 had a growth hormone (GH)-secreting PA, an adrenocorticotropic hormone (ACTH)-secreting PA, a nonfunctional PA (NFPA) and a mix-hormones secreting PA, respectively. There was a statistically significant difference between patients with and without EIG regarding types of PAs (P = 0.000). Post-hoc tests demonstrated that GH-secreting PAs (P = 0.0003) and mix-hormones secreting PAs (P = 0.0000) are significantly more invasive, while NFPAs (P = 0.0000) are less invasive. There was not a statistically significant difference between the invasion sites and different types of PAs (P = 0.122).

CONCLUSION

Among different histological subtypes of PAs, GH-secreting PAs revealed a remarkable tendency for EIG with normal sellar cavity size. The extra-sellar tumor extension with a normal sella did not correlate with atypical histology. Considering EIG patterns, surgeons should be vigilant to investigate and follow the tumor spreading to its enclosing boundary during surgery, the clival part of sphenoid bone should be more exposed, and both inferomedial and lateral borders of the sphenoid sinus should be carefully explored in order to remove the tumor.

The utility of dynamic MRI in differentiating the hormone-producing ability of pituitary adenomas

PURPOSE

To investigate the relationship between dynamic magnetic resonance imaging (MRI) findings and hormonal activity in pituitary adenomas.

METHODS

We retrospectively evaluated the dynamic MRI findings in 244 patients with pathologically confirmed pituitary adenomas and a diagnosis of clinically active prolactin (PRL)-producing adenomas. Among the 244 pituitary adenomas, 55, 16, 6, and 4 produced growth hormone (GH), PRL, adrenocorticotropic hormone, and thyroid-stimulating hormone, respectively, while 163 were non-functioning (NF) adenomas. For each adenoma, we calculated the washout rate (WR) and early (EER) and delayed (DER) tumour-to-normal-tissue enhancement ratios.

RESULTS

The respective mean values of the WR, EER, and DER were 9.4%, 75.2%, and 64.5% for GH-producing adenomas; 6.2%, 117.1%, and 106.2% for PRL-producing adenomas; and 5.4%, 116.7%, and 108.7% for NF adenomas. GH-producing adenomas had significantly lower EER and DER values than PRL-producing (P < 0.001) and NF adenomas (P < 0.001). In ROC analysis of GH-producing and non-GH-producing adenomas, the areas under the curves of WR, EER, and DER were 0.593, 0.825, and 0.857, respectively.

CONCLUSION

There are differences in dynamic MRI features between GH-producing and non-GH-producing adenomas, which suggests that EER and DER may be useful for diagnosing GH-producing adenomas.

Cystic appearance on magnetic resonance imaging in bihormonal growth hormone and prolactin tumors in acromegaly

PURPOSE

To investigate demographic, imaging and laboratory characteristics, and treatment outcomes of acromegaly patients who have bihormonal (BA) growth hormone (GH) and prolactin (PRL) immunoreactive adenomas compared to patients who have densely granulated GH adenomas (DGA) and sparsely granulated GH adenomas (SGA).

METHODS

Retrospective review of single-center surgically treated acromegaly patients; pathology was analyzed by a single neuropathologist using 2017 WHO criteria. Preoperative magnetic resonance imaging was assessed to evaluate tumor size, cystic component, invasion and T2 signal intensity.

RESULTS

Seventy-seven patients; 19 BA (9 mammosomatotroph and 10 mixed GH and PRL adenomas) were compared with 30 DGA, and 28 SGA. Patients with BA were older than SGA (49.6 vs 38.5 years, p = 0.035), had a higher IGF-1 index (3.3 vs 2.3, p = 0.040) and tumors were less frequently invasive (15.8% vs 57.1%, p = 0.005). BA more frequently had a cystic component on MRI than both SGA and DGA (52.6% vs 14.3%, and 22%, p = 0.005 and 0.033, respectively). When all histological types were combined, biochemical remission postoperatively was more common in non-cystic than cystic tumors (50% vs 22.5%, p = 0.042). Somatostatin receptor ligand response rate was 66.7%, 90.9% and 37.5% in BA, DGA and SGA patients, respectively (p = 0.053).

CONCLUSION

Imaging characteristics are an increasingly important adenoma behavior determinant. An adenoma cystic component may suggest that a GH adenoma is a BA. Cystic tumors exhibited lower rates of surgical remission in this series; therefore, optimized individual patient treatment is needed, as patients could be candidates for primary medical treatment.

Associations of Ki-67 Labeling Index with Clinical and Paraclinical Features of Growth Hormone-Secreting Pituitary Adenomas: A Single Center Report from Iran

BACKGROUND

Acromegaly is a rare disorder resulting from benign growth hormone (GH)-secreting pituitary adenomas in 90% of the cases. In recent years, many researchers have studied the Ki-67 index level of pituitary tumors and its relationship with demographics, biochemical parameters, clinical behavior, and recurrence rate.

OBJECTIVES

This study aimed to evaluate the correlation of Ki-67 index level with clinicoradiological and endocrinological parameters in confirmed GH-secreting pituitary adenomas, as well as with the surgical response and medical treatment after surgery.

METHODS

We collected the medical and pathologic records of 49 patients with GH-secreting pituitary adenoma who underwent surgeries from 2008 to 2017 in Shariati hospital affiliated to Tehran University of Medical Sciences.

RESULTS

According to MRI reports, 94% of the tumors were macroadenomas. The MRI findings also revealed the median maximal adenoma diameter of 18.5 mm. About 40% of the patients achieved remission three months after the surgery. Younger patients had a significantly higher Ki-67 index level (P = 0.036). We did not observe any significant difference in the Ki-67 index level regarding gender, tumor type, maximal tumor diameter, tumor invasiveness, tumor secretory type, and remission. Interestingly, the Ki-67 index level was negatively correlated with the insulin-like growth factor-1 (IGF-1) level at the last follow-up (P = 0.02). In logistic regression analysis, patients with higher preoperative GH serum levels had a better outcome.

CONCLUSIONS

Our results indicated a negative correlation between age and Ki-67 index level. However, there was no association between the Ki-67 index level and some tumor behaviors, as well as short- and long-term remission.

Clinicopathological significance of baseline T2-weighted signal intensity in functional pituitary adenomas

PURPOSE

To assess baseline T2-weighted signal intensity (T2-WSI) of functional pituitary adenomas (FPA), and to investigate the relationship of baseline T2-WSI with clinical features, histopathological granulation patterns, and response to treatment in patients with acromegaly, prolactinoma and Cushing's disease (CD).

METHODS

Somatotroph adenomas (n = 87), prolactinomas (n = 78) and corticotroph adenomas (n = 29) were included in the study. Baseline T2-WSI findings (grouped as hypo-, iso- and hyperintense) were compared with hormone levels, tumor diameter, granulation patterns and response to treatment.

RESULTS

Somatotroph adenomas were mostly hypointense (53%), prolactinomas were dominantly hyperintense (55%), and corticotroph adenomas were generally hyperintense (45%). Hyperintense somatotroph adenomas were larger in size with sparsely granulated pattern and tumor shrinkage rate was lower after somatostatin analogues (SSA) (p = 0.007, p = 0.035, p = 0.029, respectively). T2 hypointensity was related with higher baseline IGF-1% ULN (upper limit of normal) levels and a better response to SSA treatment (p = 0.02, p = 0.045, respectively). In female prolactinomas, hyperintensity was correlated with a smaller adenoma diameter (p = 0.001). Hypointense female prolactinomas were related to younger age at diagnosis, higher baseline PRL levels and dopamine agonist (DA) resistance (p = 0.009, p = 0.022, p < 0.001, respectively). Hyperintense corticotroph adenomas were related to larger adenoma size and sparsely granulated pattern (p = 0.04, p = 0.017, respectively). There was no significant difference in the recurrence with T2WSI in CD.

CONCLUSION

Baseline hypointense somatotroph adenomas show a better response to SSA, whereas hypointensity was related to DA resistance in female prolactinomas.

Ventriculitis from a pituitary prolactinoma: bacterial or chemical?

We report the case of a 70-year-old man presenting with pituitary apoplexy from a macroprolactinoma and ventriculitis. It was not possible to distinguish a bacterial or chemical origin, on the basis of his clinical presentation, laboratory studies and imaging, highlighting the importance of prompt imaging and attainment of CSF cultures, in making the diagnosis.

Evaluation of diffusivity in pituitary adenoma: 3D turbo field echo with diffusion-sensitized driven-equilibrium preparation

OBJECTIVE

Diffusivity of pituitary adenoma has not been investigated fully. The purpose of this study was to evaluate the feasibility of turbo field echo with diffusion-sensitized driven-equilibrium (DSDE-TFE) preparation for pituitary adenoma in the sella turcica and unaffected anterior lobe of the pituitary gland.

METHODS

This retrospective study included 23 adult patients with pituitary adenomas. Among them, 6 each were prolactin-producing adenomas and growth hormone-producing adenomas (GH) and the remaining 11 were non-functioning adenomas (NON). The apparent diffusion coefficients (ADCs) were measured in the pituitary adenoma and in the unaffected pituitary gland using coronal reformatted plane.

RESULTS

All pituitary adenomas were clearly visualized on DSDE-TFE and ADC maps without obvious geometrical distortion. There were no statistically significant differences in ADC of the all pituitary adenoma (1.50 ± 0.61 × 10(-3) mm(2) s(-1)) and the unaffected anterior lobe of the pituitary gland (1.49 ± 0.37 × 10(-3) mm(2) s(-1), p = 0.99). The ADC in prolactin-producing adenomas (2.04 ± 0.76 × 10(-3) mm(2) s(-1)) was significantly higher than that in GH (1.26 ± 0.47 × 10(-3) mm(2) s(-1); p < 0.05) and NON (1.33 ± 0.42 × 10(-3) mm(2) s(-1); p = 0.04). There was no statistically significant difference between GH and NON (p = 0.97). The intraclass correlation coefficient for ADC was 0.985 in adenomas and 0.635 in unaffected glands.

CONCLUSION

With its insensitivity to field inhomogeneity and high spatial resolution, DSDE-TFE proved a feasible method for evaluating the diffusivity in the pituitary gland and adenoma.

ADVANCES IN KNOWLEDGE

DSDE-TFE could enable us to assess ADC of pituitary adenoma in the sella turcica with high resolution and few susceptibility artefacts.

Increased micronucleus, nucleoplasmic bridge, nuclear bud frequency and oxidative DNA damage associated with prolactin levels and pituitary adenoma diameters in patients with prolactinoma

Prolactinoma is the most common pituitary tumor. Most pituitary tumors are benign, but they often are clinically significant. We investigated cytokinesis-block micronucleus cytome (CBMN cyt) assay parameters and oxidative DNA damage in patients with prolactinoma to assess the relations among age, prolactin level, pituitary adenoma diameter and 8-hydroxy-2'-deoxyguanosine (8-OHdG) level in patients with prolactinoma. We investigated 27 patients diagnosed with prolactinoma and 20 age- and sex-matched healthy controls. We measured CBMN cyt parameters and plasma 8-OHdG levels in peripheral blood lymphocytes of patients with prolactinoma and controls. The frequencies of micronucleus (MN), nucleoplasmic bridge, nuclear bud, apoptotic and necrotic cells, and plasma 8-OHdG levels in patients with prolactinoma were significantly greater than controls. MN frequency was correlated positively with age, prolactin levels and pituitary adenoma diameters in patients with prolactinoma. The increased chromosomal and oxidative DNA damage, and the positive correlation between MN frequency, prolactin levels and pituitary adenoma diameters may be associated with increased risk of cancer in patients with prolactinoma, because increased MN frequency is a predictor of cancer risk.

Sellar Toxoplasmosis and Nonfunctioning Pituitary Adenoma

BACKGROUND

Sellar toxoplasmosis is associated with congenital infections or immunodeficiency. The finding of Toxoplasma bradycysts in a pituitary adenoma is very unusual.

CASE DESCRIPTION

An otherwise healthy 27-year-old woman presented with secondary amenorrhea and moderately elevated prolactin levels. A macroprolactinoma was suspected on magnetic resonance imaging, and cabergoline was initiated. Although dopamine levels decreased, the tumor did not show significant shrinkage; after 2 years, transsphenoidal resection was indicated to clarify the diagnosis and to cure hyperprolactinemia. Histology showed an inactive pituitary adenoma and Toxoplasma bradycysts. Seropositivity for Toxoplasma gondii, but neither immunodeficiency nor intracerebral spread, was found. During a postoperative follow-up period of 15 months, the patient did not show any recurrence.

CONCLUSIONS

Sellar toxoplasmosis in conjunction with pituitary adenoma is extremely rare. Nonfunctioning lesions should be suspected in cases of sellar masses and moderate hyperprolactinemia.

Growth patterns of pituitary adenomas and histopathological correlates

CONTEXT

The factors associated with pituitary adenoma (PA) growth rate remain unclear.

OBJECTIVE

The objective of the study was to establish whether the preoperative growth and extension pattern of PA can predict postoperative growth rate and recurrence in addition to whether the PA growth rate correlates with proliferation and growth factor expression.

PATIENTS

One hundred fifty-three consecutive patients who underwent surgery for pituitary adenoma from 1999 to 2011 at Toronto Western Hospital were identified.

MAIN OUTCOME MEASURES

The PA growth rate was measured both pre- and postoperatively, and its association with patient demographics, magnetic resonance imaging, and histolopathological parameters was determined.

RESULTS

The preoperative growth rate was associated with age (P = .0001), suprasellar growth (P = .003), the presence of a cyst/hemorrhage (P = .004), the mindbomb homolog-1 (P = .005), fibroblast growth factor receptor-4 positivity (P = .047), and p27 negativity (P = .007). After surgery, there were 34.6% residual volumes, which were associated with older age (P = .038) and also with growth patterns including anterior, posterior, suprasellar, and cavernous sinus extension (P = .001); 43.3% of these residuals grew and postoperative growth rate was calculated. Pre- and postoperative growth rates were correlated (r = 0.497, P = .026). Postoperative growth rate was associated with age (P = .015) and gender (P = .017).

CONCLUSIONS

Our data suggest that the growth rate of PAs are influenced by various patient- and tumor-specific characteristics including the age and sex of the patient, the specific subtype of PA, its hormonal activity, its immunohistochemical profile including the mindbomb homolog 1 labeling index status, and its preponderance for different growth directions relative to the pituitary fossa. Furthermore, the pre- and postoperative PA growth rates were correlated, suggesting that postoperative PA growth rates can be predicted, in part, by preoperative growth rates, thus better informing postoperative outcome.

Geometric survey on magnetic resonance imaging of growth hormone producing pituitary adenoma

Apart from the radiologic features regarding size and invasiveness, we had noticed some differences in morphology among types of pituitary adenomas. We conducted this study to verify the differences in radiologic morphology between growth hormone producing pituitary adenomas (GHoma) and nonfunctioning pituitary adenomas (NFoma). Pre-surgical magnetic resonance images (MRIs) were assessed in 50 cases of GHoma and 50 cases of NFoma. Geometric parameters on MRI were set in accordance with sellar anatomy. Intensity of T1-weighted image was not different between the two groups, but hypo-intensity of T2-weighted image was more frequently seen in GHoma. Predominant inferior extension of tumor was seen mostly in GHoma (88 vs. 38%). Extension of the tumor to the superior compartment of cavernous sinus was more frequent in NFoma. Pituitary gland was generally located superior to GHoma and postero-superior to NFoma. Growth characteristics of pituitary adenoma were confirmed to differ between GHoma and NFoma.

Imaging the pituitary and parasellar region

Magnetic resonance imaging is the fundamental imaging tool for the evaluation of tumors and other lesions of the pituitary gland and infundibulum. Abnormalities may arise within the pituitary itself, from vestigial embryologic remnants, or from surrounding tissues. Correct diagnosis rests on accurate assessment of lesion location, imaging appearance, and clinical presentation. This article reviews the radiologic evaluation of lesions within the sella and suprasellar cistern, focusing on common masses and pseudomasses of the pituitary and sellar region that neurosurgeons are most likely to encounter in clinical practice.

[Spinal cord infarction]

Infarction of the spinal cord can cause a variety of symptoms and neurological deficits because of the complex vascular supply of the myelon. The most common leading symptom is distal paresis ranging from paraparesis to tetraplegia caused by arterial ischemia or infarction of the myelon. Venous infarction, however, cannot always be distinguished from arterial infarction based on the symptoms alone.Modern imaging techniques, such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA) assist in preoperative planning of aortic operations to reliably identify not only the most important vascular structure supplying the spinal cord, the artery of Adamkiewicz, but also other pathologies such as tumors or infectious disorders. In contrast to CT, MRI can reliably depict infarction of the spinal cord.

Magnetic resonance imaging as a predictor of response to somatostatin analogs in acromegaly after surgical failure

CONTEXT

Transsphenoidal surgery is considered first-line therapy for acromegaly; however, there is often a need for adjunctive therapy. Somatostatin analogs (SSA) have greatly improved the effectiveness of medical treatment, but one third of patients are resistant.

OBJECTIVE

The aim was to evaluate whether magnetic resonance imaging (MRI) signal could predict long-term response to SSA in patients with active acromegaly after neurosurgery.

PATIENTS AND METHODS

Sixty-two patients who were active acromegalic after surgery were included in this retrospective study. Remaining pituitary tumor was classified as hyper-, iso-, or hypointense by evaluating T2-weighted MRI signal. Treatment with SSA at maximal effective doses was prescribed and evaluated at 6 and 12 months by monitoring IGF-I, GH, and T2 MRI.

RESULTS

Complete response to SSA treatment (defined as normal IGF-I) at 6 months was observed in 30%, partial response (defined as IGF-I between 2 and 3 sd score) in 15%, and no response in 55% of patients. At 12 months, 28, 20, and 52% were observed, respectively. MRI signal was hypointense in 40%, hyperintense in 48%, and isointense in 12%. At 6 months, complete response to SSA was observed in 71% of cases having hypointense MRI signal and in 20% of hyperintense (P = 0.04). At 12 months, 62% of hypointense remained well controlled, whereas in the hyperintense group, good, partial, or no response results did not change from that observed at 6 months (P = 0.04).

CONCLUSION

In active acromegalic patients after surgery, a hypointense T2-weighted MRI signal is associated with a better response to SSA treatment at 6 and 12 months.

Patterns of extrasellar extension in growth hormone–secreting and nonfunctional pituitary macroadenomas

Object

Growth patterns of pituitary adenomas have been observed to vary by histopathological subtype. The authors aimed to analyze variations in the patterns of extrasellar extension of nonfunctional macroadenomas (NFMAs) and growth hormone (GH)–secreting macroadenomas.

Methods

A retrospective review was conducted of data obtained in 75 patients who underwent transsphenoidal operations for histologically confirmed NFMAs (50 patients) and GH-secreting macroadenomas (25 patients) at the Brigham and Women's Hospital over an 18-month period. Patients with microadenomas and prior operations were excluded from the analysis. Preoperative MR images were reviewed to assess patterns of extrasellar extension in the varying tumor subtypes.

Results

The mean maximal tumor diameter in NFMAs and GH-secreting macroadenomas was 26 and 16 mm, respectively (p < 0.0001). Extension of the NFMAs occurred into the following regions: infrasellar, 23 patients (46%); suprasellar, 41 patients (82%); and cavernous sinus, 20 patients (40%). Extension of GH-macroadenomas occurred into the following regions: infrasellar, 18 patients (72%); suprasellar, 4 patients (16%); and cavernous sinus, 4 patients (16%). Compared with GH-adenomas, NFMAs were more likely to develop suprasellar extension (82% vs 16%, p < 0.0001), cavernous sinus extension (40% vs 16%, p = 0.04), and isolated suprasellar extension (30% vs 4%, p = 0.0145). GH-macroadenomas had higher overall rates of infrasellar extension (72% vs 46%, p < 0.05), and isolated infrasellar extension (52% vs 6%, p < 0.0001). Of the 13 GH-macroadenomas with isolated infrasellar extension, 5 (42%) met WHO criteria for atypical adenomas.

Conclusions

Substantial differences in extrasellar growth patterns were observed among varying histological subtypes of pituitary macroadenomas. Despite smaller tumor diameters, GH-macroadenomas demonstrated a proclivity for infrasellar extension, whereas NFMAs exhibited preferential extension into the suprasellar region.

Microsurgical anatomy of the diaphragma sellae and its role in directing the pattern of growth of pituitary adenomas

OBJECTIVE

To evaluate the anatomic aspects of the diaphragma sellae and its potential role in directing the growth of a pituitary adenoma.

METHODS

Twenty cadaveric heads were dissected and measurements were taken at the level of the diaphragma sellae.

RESULTS

The diaphragma sellae is composed of two layers of dura mater. There is a remarkable variation in the morphology of the diaphragm opening. The average anteroposterior distance of the opening was 7.26 mm (range, 3.4-10.7 mm) and the average lateral-to-lateral distance was 7.33 mm (range, 2.8-14.1 mm).

CONCLUSION

The variability in the diameter of the opening of the diaphragma sellae could explain the growth of pituitary tumors toward the cavernous sinus or toward the suprasellar region.

Pituitary apoplexy during treatment of cystic macroprolactinomas with cabergoline

Pituitary apoplexy is a rare and life-threatening clinical condition caused by hemorrhage and/or infarction of the pituitary gland or adenoma. Although pituitary apoplexy is usually spontaneous, it has been associated with numerous precipitating factors, such as bromocriptine use. However, reports of pituitary apoplexy during cabergoline therapy are scarce. We report three patients with cystic macroprolactinomas who developed pituitary apoplexy during cabergoline treatment.

Comparison of growth hormone-producing and non-growth hormone-producing pituitary adenomas: imaging characteristics and pathologic correlation

PURPOSE

To identify characteristic features of growth hormone (GH)-producing pituitary adenomas.

MATERIALS AND METHODS

A total of 174 pathologically proven pituitary adenomas were evaluated retrospectively on magnetic resonance (MR) images to determine the signal intensity (on T2-weighted images), maximum diameter, and amount of suprasellar and infrasellar extension. For microadenomas, sellar depth was also measured. GH-producing adenomas were classified at histologic evaluation as densely or sparsely granulated. Specimens from 38 adenomas were stained to assess the amounts of fibrous tissue, iron, and amyloid they contained. Results were correlated with the size and hormonal activity of adenomas by using the chi2, unpaired t, and Mann-Whitney U tests.

RESULTS

Among 174 pituitary adenomas, 42 were GH-producing adenomas. Of these, 16 were densely granulated, and 24 were sparsely granulated (two histologic specimens were lost). Signal intensity was evaluated among 153 adenomas. On T2-weighted MR images, hypointensity was seen more commonly in adenomas that produced GH (16 of 40 cases [40%]; P <.001) than in those that did not; hypointensity was nearly exclusive to densely granulated GH-producing adenomas. The amounts of amyloid, fibrous tissue, and iron contained in adenomas demonstrated little relationship with signal intensity. Average suprasellar extension was significantly smaller in adenomas that produced GH (-0.8 mm) than in those that did not (5.3 mm) (P <.001). GH-producing adenomas tended to demonstrate infrasellar extension rather than suprasellar extension. Average sellar depth associated with GH-producing microadenomas (13.3 mm) was significantly greater than for non-GH-producing microadenomas (9.7 mm; P <.001).

CONCLUSION

Characteristic features regarding growth direction and T2 signal intensity can be identified for GH-producing adenomas.

(99m)Technetium pentavalent dimercaptosuccinic acid scintigraphy in the follow-up of clinically nonfunctioning pituitary adenomas after radiotherapy

BACKGROUND

It is still difficult to differentiate pituitary adenoma remnants from postradiotherapy fibrosis by computed tomography (CT) or magnetic resonance imaging (MRI), especially in patients with clinically nonfunctioning pituitary adenomas (NFA), lacking circulating markers to follow disease progression or cure.

OBJECTIVE

We investigated the usefulness of scintigraphy with technetium-99m pentavalent dimercaptosuccinic acid [(99m)Tc(V)DMSA], shown previously to detect most pituitary GH- and PRL-secreting adenomas and NFA, with tumour-to-background ratios (T/B) as high as 25-fold.

PATIENTS

Eighteen patients with NFA (study group), 10 patients with GH- and three patients with PRL-secreting adenomas (control group), all of whom had undergone previous surgery.

DESIGN

The study was an open longitudinal design. Pituitary CT/MRI and (99m)Tc(V)DMSA scintigraphy was performed before and 1, 3 and 5 years after conventional radiotherapy. Tumour size was measured as maximal diameter of the residual lesion, while uptake of (99m)Tc(V)DMSA was measured as a T/B ratio.

RESULTS

At study entry, pituitary (99m)Tc(V)DMSA uptake was found in 13 NFA (72.2%), seven GH-secreting (70%) and all PRL-secreting adenomas; remnant tumour was documented by CT/MRI in all 31 patients. Maximal remnant diameter was significantly higher in patients with positive (13.3 +/- 0.9 mm) than in those with negative scintigraphy (7.0 +/- 0.3 mm, P < 0.001). During the 5-year follow-up postradiotherapy, a significant decrease in (99m)Tc(V)DMSA uptake (9.7 +/- 0.8 vs. 3.2 +/- 0.5, P < 0.0001) occurred in all but three patients. Two NFA patients died of tumour invasion 19 and 36 months after radiotherapy and one acromegalic patient had no change in his hormone levels. In the eight negative patients (five NFA and three GH), scintigraphy remained negative throughout follow-up. A remarkable shrinkage of the remnant tumour was observed in both the patients with negative (from 7.0 +/- 0.3 to 1.9 +/- 0.6 mm, P < 0.001) and in those with positive scintigraphy (from 13.3 +/- 0.9 to 7.3 +/- 0.6 mm, P < 0.001). At the end of the study, CT/MRI showed evident remnant tumour in 13 of 16 NFA (81.2%), nine GH-secreting (90%) and all three prolactinomas (100%), while the scintigraphy was negative (T/B < 1) or faintly positive (T/B 1-2) in eight of 16 NFA (50%), five GH-secreting (50%) and one prolactinoma (33.3%).

CONCLUSIONS

Functional imaging of pituitary remnant adenomas (> 10 mm in size) by (99m)Tc(V)DMSA depicts viable pituitary adenoma remnants. This approach may be of clinical value in patients with clinically nonfunctioning adenomas to monitor the effects of radiotherapy.

Evaluation of pituitary microadenomas with dynamic MR imaging

PURPOSE

To evaluate the use of keyhole dynamic magnetic resonance (MR) imaging in the evaluation of women with borderline hyperprolactinemia.

PATIENTS AND METHODS

We investigated 30 patients (mean age 31.6+/-4.3 years) with moderate hyperprolactinemia and clinically suspected microadenomas on T1-weighted spin echo (SE) sequences (repetition time (TR)/echo time (TE) 625/15 ms) with keyhole dynamic imaging and contrast enhancement of the pituitary gland. The probability of lesion presence according to MR criteria was ranked on a five-grade scale and compared with standard examinations of the hypophysis before and after intravenous administration of contrast media.

RESULTS

The probability for lesion presence showed a trend toward lower scores on standard SE sequences and higher scores with dynamic imaging (P=0.067).

CONCLUSION

Dynamic keyhole imaging of the pituitary gland could help establish a diagnosis of microadenomas with a higher probability.

Cerebrospinal fluid rhinorrhea associated with untreated prolactinoma--case report

An 80-year-old female presented with non-traumatic cerebrospinal fluid (CSF) rhinorrhea due to untreated prolactinoma, with simultaneous development of bilateral leg pains and gait disturbance due to lumbar canal stenosis. Neuroimaging showed an intrasellar mass extending into the sphenoid sinus, right cavernous sinus, and suprasellar cistern. Computed tomography cisternography clearly showed the CSF pathway through the tumor. Subtotal removal of the tumor and reconstruction of the sellar floor via a transsphenoidal approach resulted in resolution of the CSF rhinorrhea. Both the invasive features and/or spontaneous shrinkage of the tumor might have created the abnormal CSF pathway. The clinical manifestation of lumbar canal stenosis might be triggered by such profound CSF leakage.

Aggressive giant pituitary adenoma presenting as a nasopharyngeal mass: magnetic resonance imaging and pathologic findings

We report a giant pituitary adenoma with aggressive histologic features that prominently invaded the nasopharynx. Magnetic resonance imaging (MRI) demonstrated a large heterogeneous nodular mass that was hypointense to isointense on T1-weighted images and mixed hypointense, isointense, and hyperintense on T2-weighted images. The mass measured 7.5 x 5 x 7 cm, extending from the nasopharynx posteriorly through the clivus, and superiorly through the paranasal sinuses, and sellar-suprasellar region. After contrast administration, heterogeneous nodular enhancement was noted. A nasopharyngeal neoplasm extending into the sella was suspected because voice change and nasal speech long preceded the patient's visual symptoms. A biopsy disclosed an aggressive, infiltrating, hemorrhagic tumor, which was diagnosed as a non-secreting pituitary macroadenoma. This report indicates that pituitary adenomas may grow invasively to tremendously large sizes resulting in their initial presentation as nasopharyngeal masses.

Modern imaging techniques in GH secretory disorders

Magnetic resonance images of the pituitary-hypothalamic area in patients with GH secretory disorders, divided into two groups (hypersecretory and hyposecretory), were studied. In the first group there were 42 patients with pituitary adenoma; size, signal characteristics, direction of growth, and type of enhancement were analyzed and compared with similar studies in 40 age and sex matched control patients with non-GH secreting pituitary adenomas. No significant differences were found except for a higher frequency of chiasm involvement and a more pronounced contrast enhancement in the control group. The hyposecretory group was composed of 101 patients with congenital idiopathic growth hormone deficiency (CIGHD). MR revealed morphological abnormalities consisting of hypoplastic anterior pituitary and ectopic posterior pituitary (PPE) in 59 patients, without evidence of a complete pituitary stalk; in 42 patients the posterior pituitary was in normal position and the pituitary stalk visible. The group with PPE showed a greater frequency of multiple pituitary hormone deficiency (51% vs 12%), breech delivery (30% vs 7%) and associated congenital brain anomalies (12% vs 7%). These data suggest that CIGHD could be the result of a congenital midline brain anomaly in a significant proportion of patients.