The evolution of pituitary cysts in growth hormone-treated children

OBJECTIVES

We have previously shown that pituitary cysts may affect growth hormone secretion. This study sought to determine cyst evolution during growth hormone treatment in children.

METHODS

Forty-nine patients with short stature, a pituitary cyst, and at least two brain MRI scans were included. The percent of the pituitary gland occupied by the cyst (POGO) was calculated, and a cyst with a POGO of ≤15% was considered small, while a POGO >15% was considered large.

RESULTS

Thirty-five cysts were small, and 14 were large. Five of the 35 small cysts grew into large cysts, while 6 of the 14 large cysts shrunk into small cysts. Of 4 cysts that fluctuated between large and small, 3 presented as large and 1 as small. Small cysts experienced greater change in cyst volume (CV) (mean=61.5%) than large cysts (mean=-0.4%). However, large cysts had a greater net change in CV (mean=44.2 mm³) than small cysts (mean=21.0 mm³). Older patients had significantly larger mean pituitary volume than younger patients (435.4 mm³ vs. 317.9 mm³) and significantly larger mean CV than younger patients (77.4 mm³ vs. 45.2 mm³), but there was no significant difference in POGO between groups.

CONCLUSIONS

Pituitary cyst size can vary greatly over time. Determination of POGO over time is a useful marker for determining the possibility of a pathologic effect on pituitary function since it factors both cyst and gland volume. Large cysts should be monitored closely, given their extreme, erratic behavior.

PMON330 The Relationship between Pituitary Volume and Chiari Malformation in Growth Hormone Deficiency and Idiopathic Short Stature

Patients with a small posterior cranial fossa may present with cerebellar tonsillar herniation through the foramen magnum, known as Chiari malformation (CM). The relationship between CM, pituitary volume (PV), and growth hormone deficiency (GHD) has not yet been explored and is the subject of this abstract. This study seeks to compare the differences in PV in short patients with CM with a diagnosis of either GHD or idiopathic short stature (ISS), to normal controls (NCs). The database of a Peds Endo Center between 2013-21 was queried for patients with CM and who had undergone MRI evaluation. Patients were separated into 4 groups: CM and GHD, CM and ISS, GHD without CM, and ISS without CM. These groups’ PV results were compared with NCs who we previously reported. The ages of short patients with CM (n=29) were compared to the ages of NCs (n=170); no significant difference was found (p = 0.12). The MN and MD PV for patients with GHD alone were 230.8 ± 89.64 and 217.62mm3, respectively. The MN and MD PV for patients with GHD and CM (n=23) were 246.55 ± 128.0 and 200.5mm3, respectively. The MN and MD PV for CM and ISS (n=6) were 671.54 ± 350.25 and 619.55mm3, respectively. The MN and MD PV for NCs were 364.0 ± 145.2 and 346.0mm3, respectively. The PV of patients with GHD alone were compared to the PV of patients with both GHD and CM; there was no significant difference found (p=1.0). Next, the PV of patients with GHD alone were compared to the PV of patients with both ISS and CM which showed that patients with GHD alone had significantly smaller PV compared to patients with both ISS and CM (p<0.05). Lastly, we compared the PV of patients with both GHD and CM versus patients with both ISS and CM, which showed that patients with both GHD and CM had significantly smaller PVs compared to patients with both ISS and CM (p<0.05). The PV of short patients with CM (n=29) were compared to the PV of NCs (n=170) and there was no significant difference found (p = 0.58). Our study demonstrates that PV is smaller in patients with GHD regardless of whether they have CM or not. We speculate that CM appears to be a radiological finding with no significant impact on PV, whereas GHD appears to have a significant impact on PV. Therefore we speculate the small PV exhibited in patients with CM and GHD appear to be related to GHD. A larger sample size will be needed to further elaborate on this concept.

Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

PSAT104 Predicting Response to Growth Hormone Therapy with Pituitary Volume and The Growth Hormone Stimulation Test

Background

Patients with diminished growth hormone (GH) secretion are candidates for GH therapy (GHT). The GH stimulation test (GHST) is considered the gold standard for the diagnosis of GH deficiency (GHD), yet its efficacy has been questioned. In this study we explore the GHST and PV's ability to define GHD and determine their individual ability to predict GHT outcomes.

Subjects and Methods

A database at a Pediatric Endocrinology center was queried for patients aged 6-18 yrs who underwent a GHST, MRI, and GHT between 1/2018 - 1/2021. Patients with a first follow up (FU) between 3 and 9 months were included; of these patients, second FUs were included if they occurred between 9 and 15 months. Patients with relevant comorbidities, those with GHST peak ≥ 10.0 ng/mL, and nonadherent patients were excluded. MRIs were acquired on a Philips 1.5 or 3.0 T scanner (2mm slices) and PV was calculated using the ellipsoid formula (LxWxH/2).

PV and height were converted to SDS. Response to treatment was defined as change in height SDS over the assessed time interval. A multiple linear regression was utilized to analyze the response to GHT relative to peak GH and PV, with initial height and age at stimulation included as covariates. The relationship between peak GH and PV SDS was analyzed with a Pearson correlation

Results

The first FU ranged between 3.1 and 8.9 months, and the second FU ranged between 9.0 and 14.9 months. 145 patients had one FU, and 83 patients had two FUs. Peak GH and PV SDS were not correlated (r=0.03). Patients who were relatively shorter for their age and gender at stimulation had higher growth rates in the first interval, but not in the second interval. Both PV and peak GH provided information about response to GHT. PV SDS negatively predicted the relative growth response to treatment in the first interval (slope=-0.03, p=0.048). However, PV only explained 3.7% of variation in growth. PV SDS was not a useful predictor of response in the second interval (slope=-0.01, p=0.693). Peak GH was a predictor of response to GHT in the first interval only after accounting for age at stimulation and initial height (slope=-0.01, p=0.032; r2=0.01). Peak GH was a predictor of response in the second interval (slope=-0.02, p=0.040), explaining 5.1% of the variation in growth.

Conclusion

Since peak GH and PV were not correlated, they likely reflect different physiological processes. PV and peak GH both provide information about response to GHT, so they should both be utilized to determine eligibility for GHT.

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

RF26 | PSAT109 The Prevalence of Abnormalities in Cranial MRIs in Children with Short Stature Prior to Growth Hormone Therapy

Background

MRIs of the brain in patients with short stature have shown a number of abnormalities. Some of these radiological findings can have clinical significance. Here we have looked at MRI results in such a population.

Objective

To review the value and significance of the prevalence of all abnormal MRI findings of children with short stature who are to undergo growth hormone therapy (GHT).

Materials and methods

This study involved a retrospective review of MRI findings in all children prescribed GHT within a pediatric health network's database from Jan 2020 to Aug 2021. Post-gadolinium contrast enhanced brain and pituitary MRIs utilizing 2 mm slices were used to calculate pituitary volume. Pituitary volume was calculated using the ellipsoid formula (LxWxH/2). Pediatric patients diagnosed with non-acquired GHD or ISS, with MRIs having been performed between Jan 2020 and Aug 2021 and having been prescribed GHT by Aug 2021 were included in this study. Patients who experienced other endocrine abnormalities such as SGA, Turner Syndrome, and Noonan Syndrome were excluded. Patients with obstruction of sellar and parasellar religion due to movement artifacts or magnetic interference on their MRIs were also excluded.

Results

Of one hundred and twelve patients found, eighty one met criteria for inclusion in this study. Of the eighty one MRIs reviewed, twenty eight children, 34.6%, had normal pituitary anatomy and fifty three, 65.4%, had a pituitary abnormality. Out of the fifty three with a pituitary abnormality, forty three subjects, 81.1%, were determined to have a small pituitary volume, including significant pituitary hypoplasia. Ten subjects (18.9%) had an enlarged pituitary volume (pituitary hyperplasia). Of these ten patients who had an enlarged pituitary volume, eight were pubertal (80%). Nine children with a pituitary abnormality (16.9%) had additional structural anomalies on their MRIs. One had a small left frontal developmental venous anomaly. Two had Rathke's cleft cysts. Two had pars intermedia cysts. One had a small right parietal developmental venous anomaly. One had a small left parietal developmental venous anomaly. One had a left cerebellar tonsillar ectopia bordering on chiari malformation (.5 mm away on the coronal plane). One had a small lobulation (semi-bulbous projection) of the anterior pituitary gland, superior and anterior to the infundibular stalk.

Conclusion

Prevalence of brain abnormalities in children with short stature who are to undergo GHT is significant and warrants MRI evaluations in these subjects.

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Monday, June 13, 2022 12:58 p.m. - 1:03 p.m.

PSAT107 Evaluating Pituitary Volume and the Growth Hormone Stimulation Test in Siblings. Both Together Better Define the Etiology of Short Stature

We have shown that short children have significantly reduced pituitary volume (PV)s and have speculated PV as a cause for diminished chronic growth hormone (GH) secretion and poor growth. In this study, we further elucidate the role of PV in the etiology of short stature (SS) in a larger cohort of siblings (SBs).The database of a Peds Endo Center between 2013-21 was queried for siblings with SS who underwent a GH Stimulation test (GHST) and MRI evaluation. Their results were compared with normal controls (NCs) as previously reported. 129 SBs of 60 families were compared to 170 NCs. SBs were divided into 3 groups (GPs). GP1 (n=79) consisted of families with only GHD. GP2 (n=12) contained families with only ISS SBs. GP3 (n=38) comprised families with mixed GHD and ISS. SBs &lt;11 yrs and &gt;11 yrs were considered prepubertal (prePB) and pubertal (PB), RSP. The mean (MN) and median (MD) age for both prePB and PB SBs were significantly different (p 0.05). The 32 PB patients in GP3 had a mean PV of 316.17± 197.53 mm3, which was significantly different from that of the PB NCs of 424.6 ± 138.4 mm3 (p&lt;0.001). Out of 38 children in GP3, 18 passed the GHST and 11 of those children who passed demonstrated a small pituitary gland (61%). 78% of prePB SBs had small PVs, while 88% were GHD. 66% of PB SBs had small PVs, while 70% of PB SBs were GHD. 71% of all SBs had small PVs, while 77% were GHD. When combined, GHST and PV identify the etiology for SS in 92% of subjects. The GHST and PV together identify more patients of SS who should qualify and benefit from GH therapy than the GHST alone. Since ages were significantly different and present as a limitation to this study, future studies should strive for age match control

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

PMON331 The Natural History of Pituitary Cysts in Patients with Growth Hormone Deficiency and Idiopathic Short Stature

Background

Pituitary cysts may be implicated in short stature and affect growth hormone secretion. The natural history of cysts is not known in patients with GHD and ISS.

Objective

To characterize the progression of cyst volume (CV) and percentage of the gland occupied by the cyst (POGO) over time in GHD and ISS patients.

Subjects and Methods

A pediatric health system's database was queried for patients diagnosed with short stature and a cyst with at least one follow up MRI between 2007-21. Data up to 7 years after first follow up was included in this study. The mean and median follow up time were 1.32±1.24 and 1.00. Cysts with a POGO≤15% were considered small, while a POGO>15% were considered large.

Results

The mean and median %ΔCV for all patients for all their follow up MRIs were 38.27%±179.14 and 0%. The mean and median %ΔPOGO for all patients were 38.32%±219.85 and -5.79%. The mean and median %ΔCV for patients with a small cyst (SC) (n=34) were 61.49%±215.60 and 0%. The mean and median %ΔPOGO for patients with a SC were 61.62%±267.25 and -2.89%. The mean and median %ΔCV for patients with a large cyst(LC)(n=14) were -0.4% ±-79.25 and 0%. The mean and median %ΔPOGO for patients with a LC were -1.08%±90.50 and -15.67%. 5 of the 35(14.3%) SCs grew into LCs and stayed large while 6 of the 14 LCs shrunk into SCs. 4 cysts fluctuated between large and small: 3 started large and 1 started small. CV of patients with LCs has a significant negative correlation with time (-0.37, p=0.01). The slope of the regression line is -0.01 mm3/month. The CV of patients with SCs does not show any change in time (-0.02, p=0.84). There is no significant difference in POGO (p=0.86) or in CV (p=0.96) in GHD and ISS patients. In GHD and ISS patients, the difference in POGO is different in each group at each MRI date (p=0.02), but not in CV (p=0.38). GHD patients had an average ΔPOGO of -1.05, while ISS patients had an average ΔPOGO of 1.26.

Conclusion

POGO can change greatly over time. LCs tend to take up less of the gland over time. SCs tend not to change significantly over time, but a minority can still enlarge and need to be monitored. So far, there have been no significant clinical consequences related to these cysts.

Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Neuroendocrine expression in metastatic prostate cancer: evaluation of high throughput tissue microarrays to detect heterogeneous protein expression

The theory that poorly differentiated prostate carcinoma develops a neuroendocrine (NE) phenotype is controversial. Supportive data is variable with NE expression being observed in anywhere from 5% to 83% of prostate cancers. These percentages are derived from standard immunohistochemistry studies, which make no attempt to quantify the results. High-density tissue microarrays (TMAs), represent a novel method for evaluating up to 1000 tissue samples with a 0.6 mm diameter on a single glass slide. This high throughput technology for screening antibodies, however, requires validation to determine if TMAs are useful in evaluating heterogeneously expressed proteins such as the NE markers chromogranin A (CGA) and synaptophysin (SYN). This study compares results from standard slides to TMAs in 50 primary and metastatic prostate tumors taken from 12 rapid autopsies from men with hormone refractory prostate cancer. One hundred standard and 2 TMA slides were immunostained for CGA and SYN. Using standard slides, focal NE expression was seen in 1/12 primary prostate tumors. Overall, 13/100 (13%) standard slides showed focal NE expression for both primary and metastatic prostate tumors; NE expression was observed in 4/12 autopsy cases (33%) when all tumor sites per case were considered. 458 tissue elements (tumor and normal) were arrayed into one paraffin block. Seventy-three percent (332/458) of the elements placed into the TMA were confirmed histologically to represent tumor. Seventy-five percent (250/332) and 66% (218/332) could be evaluated for CGA and SYN expression, respectively. Six of the metastatic tumors expressed CGA and SYN or 2.4% (6/250; 95% CI = 0.9% to 5.2%) and 2.3% (6/218; 95% CI = 0.8% to 5.3%), respectively. In conclusion, only focal NE expression was observed by both methods (eg, standard and TMA slides). The focal expression in these advanced prostate tumors was unexpected given data from prostate tumor cell lines and animal models suggesting that progression to the NE phenotype parallels tumor progression. This study also supports the use of high density TMAs to screen for protein expression, even when expression is focal.