Spontaneous Regression Research Articles

Spontaneous regression of sizable herniated cervical disc

Spontaneous regression of sizable herniated cervical disc

Fine construction of gene coexpression network analysis using GTOM and RECODE detected a critical module of neuroblastoma stages 4 and 4S.

Stage 4 neuroblastoma (NBL), a solid tumor of childhood, has a poor prognosis. Despite intensive molecular genetic studies, no targetable gene abnormalities have been identified. Stage 4S NBL has a characteristic of spontaneous regression, and elucidation of the mechanistic differences between stages 4 and 4S may improve treatment. Conventional NBL studies have mainly focused on the detection of abnormalities in individual genes and have rarely examined abnormalities in gene networks. While the gene coexpression network is expected to contribute to the detection of network abnormalities, the fragility of the network due to data noise and the extraction of arbitrary topological structures for the high-dimensional network are issues. The present paper concerns the classification method of stages 4 and 4S NBL patients using highly accurate gene coexpression network analysis based on RNA-sequencing data of transcription factors (TFs). In particular, after applying a noise reduction method RECODE, generalized topological overlapping measure (GTOM), which weighs the connections of nodes in the network structure, succeeded in extracting a cluster of TFs that showed high classification performance for stages 4 and 4S. In addition, we investigated how these clusters correspond to clinical information and to TFs which control the normal adrenal tissue and NBL characters. A clustering method is presented for finding intermediate-scale clusters of TFs that give considerable separation performance for distinguishing between stages 4 and 4S. It is suggested that this method is useful as a way to extract factors that contribute to the separation of groups from multiple pieces of information such as gene expression levels.

Neuroblastoma cell lines display heterogeneity in differentiation responses

Background Neuroblastoma is the most common extra-cranial childhood solid tumour, arising during development from stalled neural crest-derived precursor cells. In a subset of children younger than 18 months of age, neuroblastoma can undergo spontaneous regression driven by differentiation, leading to great interest in developing differentiation therapies to re-direct neuroblastoma cells down their correct developmental pathway. Recently, we have shown that combinatorial treatment with the CDK4/6 inhibitor palbociclib and differentiation-inducing agent retinoic acid inhibits proliferation and drives neuronal differentiation of adrenergic-type neuroblastoma cell lines. Methods Here, we explore the differentiation potential of neuroblastoma cell lines in vitro in response to palbociclib and retinoic acid treatment using microscopy, transcriptomic and qRT-PCR analyses. Results We present evidence suggesting that neuroblastoma cells can give rise to mixtures of neural crest-derived adrenal gland cell types, and that differentiation responses correspond to changes in patterns of extracellular matrix substrate expression. Conclusions This study builds a case to further investigate and consider heterogeneity in neuroblastoma cell differentiation and the role of the extracellular matrix in these cell fate decisions.

EXTH-11. PEDIATRIC GLIOMA IMMUNE PROFILING IDENTIFIES TIM3 AS A THERAPEUTIC TARGET IN BRAF-FUSION PILOCYTIC ASTROCYTOMA

Abstract Despite being the leading cause of childhood mortality, pediatric gliomas have been relatively understudied. Repurposing of adult brain tumor immunotherapies in pediatric patients has not been successful, highlighting the need for pediatric-specific immunotherapies. Pilocytic astrocytomas (PA) are the most common pediatric glioma. While surgical resection of PA is the first-line treatment, the ten-year progression-free survival rate for patients with residual tumors is <50%. Notably, some PAs undergo spontaneous regression after partial resection, suggesting potential baseline tumor immunoreactivity. Whole transcriptome sequencing performed on a commercial platform of pediatric gliomas (n=250) showed that MAPK-driven gliomas have higher interferon signatures compared to other molecular subgroups. Single-cell sequencing identified a unique activated and cytotoxic microglia population designated MG-Act in BRAF-fused MAPK-activated PA (n=13; p < 0.05), but not in pediatric high-grade gliomas (n=5) or normal brain (n=3). TIM3 was expressed on the luminal side of endothelial cells and MG-Act, but not in the surrounding normal brain based on sequential multiplex imaging. Flow cytometry showed that TIM3 intensity is upregulated on immune cells in the PA tumor microenvironment (TME) relative to matched peripheral blood immune cells (n=6; p < 0.01). Anti-TIM3 reprogrammed fresh ex vivo immune cells from the TME of human PAs (n=3) to a pro-inflammatory cytotoxic phenotype. In a genetically engineered murine model of MAPK-driven low-grade gliomas, median survival (MS) was 252 days in mice treated with anti-TIM3 (n=21; p<0.01) relative to IgG control (MS: 110 days; n=20) or anti-PD-1 (MS: 134 days; n=20). The therapeutic activity of anti-TIM3 was abrogated in the CX3CR1 microglia knockout background. ScRNA sequencing data during the therapeutic window of anti-TIM3 in wild-type mice demonstrated enrichment of the MG-Act population within low-grade gliomas at two different longitudinal time points but not in IgG-treated controls. Together, these data indicate that anti-TIM3 should be considered for clinical trials in pediatric low-grade MAPK-driven gliomas.

CDK4/6 inhibitors display a class effect in inducing differentiation of neuroblastoma cells

Background Neuroblastoma is the most common extracranial solid tumour in infants and children, accounting for approximately 15% of paediatric cancer mortality. These tumours are unique in that a subset, namely stage MS, frequently undergo spontaneous regression or differentiation. Differentiation therapy, where cancer cells are re-routed back down their correct developmental pathway, is therefore a promising therapeutic avenue. We have previously shown that the CDK4/6 inhibitor palbociclib induces both decreased proliferation and enhanced neuronal differentiation of neuroblastoma cells in vitro. When combined with retinoic acid, already used clinically for maintenance therapy, this differentiation is enhanced. Methods Here, we investigate two additional CDK4/6 inhibitors, abemaciclib and ribociclib, to induce differentiation of the relapsed, high-risk MYCN-amplified neuroblastoma cell line SK-N-BE(2)C, with and without retinoic acid. We culture SK-N-BE(2)C cells in both adherent and three-dimensional culture and monitor proliferation and differentiation using readouts including live-imaging, immunocytochemistry, qRT-PCR and EdU incorporation. Results We find the CDK4/6 inhibitors palbociclib, abemaciclib and ribociclib all enhance retinoic acid-induced differentiation in both adherent SK-N-BE(2)C cells and 3D spheroids. Conclusions CDK4/6 inhibitors display a class effect in inducing neuronal differentiation together with retinoic acid, both in adherent neuroblastoma cell lines and three-dimensional tumour spheroids. This is an important consideration for potentially developing CDK inhibitor-induced differentiation as a therapy in the clinic.

Helicobacter pylori prevalence and its spontaneous eradication rate after distal or proximal gastrectomy for gastric cancer: A multicenter prospective cohort study

AbstractBackgroundHelicobacter pylori (H. pylori) eradication is recommended in patients undergoing endoscopic resection for early gastric cancer to reduce recurrence. However, due to the possibility of spontaneous regression secondary to dynamic changes in the remnant stomach, the immediate eradication after gastrectomy for H. pylori carriers remains unclear. This study aimed to investigate the prevalence of H. pylori in Japanese patients with gastric cancer and the spontaneous eradication rate after distal or proximal gastrectomy.MethodsThis multicenter prospective cohort study was conducted at 22 institutions. Eligibility criteria was patients over 20 years planned to undergo R0 gastrectomy for gastric cancer. The primary endpoint was spontaneous eradication rate 1 year after distal or proximal gastrectomy. The prevalence of H. pylori infection before surgery and clinical features related to spontaneous eradication were examined.ResultsA total of 1247 patients were included in this study. The preoperative H. pylori status was positive in 756 patients and negative in 491. Seventy‐nine of the negative patients had an eradication history, totaling 835 (67%) patients preoperatively infected with H. pylori. The infection status of 541 patients was examined 1 year postoperatively; 285 were negative, with a 52.7% spontaneous eradication rate. Spontaneous eradication was significantly higher in male and older patients (>70 years); other factors, such as histological type, gastrectomy method and adjuvant chemotherapy presence, did not affect the rate.ConclusionsAs spontaneous H. pylori eradication occurred in more than half of the analyzed patients, retesting for H. pylori. should be considered before postoperative eradication therapy (UMIN000020280).

Volumetric CT Assessment of In Situ Induced Hepatic Lesions in a Transgenic Swine Model

The growth rate of in situ-induced hepatic lesions in an Oncopig large animal model is quantitatively assessed. Oncopigs (n = 9) received baseline triple-phase CT scans prior to lesion induction. Lesions were subsequently induced by delivering the Ad-Cre vector to four locations in the liver. Triple-phase CT scans were obtained weekly to track the growth of the lesions. Animals were sacrificed at 14, 21, or 28 days (n = 3 in each group). The overall success rate of lesion generation was ~78%. Histopathology sections consistently revealed lesions that were highly inflammatory and consisted of a large leukocyte population without clear evidence of carcinomas. Lesions presented within imaging as hypovascular, low attenuating masses with slight contrast enhancement around the margins but little to no enhancement within the lesions themselves. The observed lesions were manually segmented on the venous phase image. Segmentation volumes were fitted to a logistic growth and decay model. Several lesions observed at earlier time points in the 28-day group had fully regressed by the time of the necropsy. The overall trend of rapid growth for the first 21 days, with spontaneous regression of the lesions being observed from day 21 to 28, suggests that the optimal window for experimental studies may be from days 14 to 21. The data and mathematical models generated from this study may be used for future computational models; however, the current model presented has moderate clinical relevance because many induced tumors resolved spontaneously within a few weeks. Awareness and careful consideration of the modest relevance and limitations of the model are advisable for each specific use case.

A Case of Moyamoya Disease With Spontaneous Regression of Posterior Choroidal Artery Aneurysm After Improvement in Obesity and Administration of an Antihypertensive Drug

A Case of Moyamoya Disease With Spontaneous Regression of Posterior Choroidal Artery Aneurysm After Improvement in Obesity and Administration of an Antihypertensive Drug

Spontaneous and post-interventional regression of cervical HPV infection.

Recent literature sources suggest that 15-20% of all malignant diseases have a viral aetiology. About 5% of these are caused by the human papillomavirus. The presence of papillomavirus is one of the strongest risk factors for development of a cervical pre-cancerous lesion and subsequent cervical cancer. The presented review provides a brief summary and characterisation of risk factors that influence spontaneous and post-interventional regression and persistence of papillomavirus in the cervical area.

Burned-out testicular cancer - case report

Introduction and Purpose Germ cell tumors of the testis are the most common malignant tumors in young men aged 15-40, although their incidence in the male population is about 1-1.5%. 90-98% of all testicular tumors originate from germ cells. There has been an increase in the incidence of testicular tumors in recent years, suggesting the influence of both genetic and environmental factors. Testicular cancer, which accounts for about 5% of all urological cancers and mainly affects young men. Most of these cancers originate from germ cells, and cases of spontaneous tumor regression are extremely rare. Aim of the study We present the case of a 36-year-old man who was found to have a left testicular tumor with negative tumor markers during physical examination and testicular ultrasound. The tumor was surgically removed, and the patient was discharged home. Histopathological examination showed that the tumor had completely necrosed, and a CT scan showed no metastasis. Results and Future directions The phenomenon of testicular tumor “burnout” has been described since 1927, but it was only in 2016 that the WHO recognized it as a separate disease entity. Despite the rarity of this phenomenon, more and more cases are being reported in the literature, allowing for a better understanding of the underlying mechanisms. It is important to remember that the tumor can give a variable clinical picture and its symptoms are not necessarily related to the location of the tumor, but to its metastasis. Physical and ultrasound examinations are key to making a correct diagnosis. Histologic features such as scar formation, intravesicular calcification, lymphoplasmocytic infiltration and testicular atrophy can help diagnose germ cell tumor. The findings of this case demonstrate the need for diagnostic vigilance, especially in patients with equivocal tumor marker results but with clinical signs of testicular tumor.

PD-L1 expression in testicular germ cell tumors undergoing spontaneous regression.

Spontaneous regression of testicular germ cell tumors is a well-known phenomenon; however, the precise mechanisms of spontaneous regression are still unknown. Our study aimed to investigate programmed death-ligand 1 (PD-L1) expression in spontaneously regressed testicular germ cell tumors, exploring the link between the immune response and spontaneous regression. From a sample of 356 testicular germ cell tumors, we singled out 5 completely regressed and 6 partially regressed tumors. In four out of six cases with partial regression, a residual seminoma component was found, while in the remaining two cases, an embryonal carcinoma component was found. Comparisons were made with 20 pure seminomas and 20 mixed germ cell tumors (MGCTs). A semiquantitative immunohistochemical analysis of PD-L1 expression in tumor cells and intra/peritumoral lymphocytes was performed. There was no PD-L1 expression in tumors with complete regression. All partially regressed tumors showed expression in intra/peritumoral lymphocytes within the tumor remnants. Expression was significantly more frequent in pure seminomas compared to MGCTs (P = 0.004). A positive correlation was demonstrated between the seminoma component and the proportion of PD-L1 positive lymphocytes, with a Kendall's Tau-b coefficient of 0.626 (P < 0.001). Tumor cells showed PD-L1 expression in three MGCTs within the embryonal carcinoma component. Our results support an immunological mechanism of spontaneous tumor regression, with the strongest potential in testicular tumors containing seminoma components. However, further research is necessary to determine the role of PD-L1 ligand more precisely in the microenvironment of spontaneously regressed tumors.

A temporal (phospho-)proteomic dataset of neurotrophic receptor tyrosine kinase signalling in neuroblastoma

Neurotrophic receptor tyrosine kinases (TrkA, TrkB, TrkC), despite their homology, contribute to the clinical heterogeneity of the childhood cancer neuroblastoma. TrkA expression is associated with low-stage disease and is often seen with spontaneous tumour regression. Conversely, TrkB is present in unfavourable neuroblastomas that often harbour amplification of the MYCN oncogene. The role of TrkC is less clearly defined, although some studies suggest its association with a favourable outcome. Understanding the differences in activity of Trk receptors that drive divergent clinical phenotypes as well as the influence of MYCN amplification on downstream Trk receptor signalling remains poorly understood. Here, we present a comprehensive label-free mass spectrometry-based total proteomics and phosphoproteomics dataset (432 raw files with FragPipe search outputs; available on PRIDE with accession number PXD054441) where we identified and quantified 4,907 proteins, 16,744 phosphosites and 5,084 phosphoproteins, derived from NGF/BDNF/NT-3 treated TrkA/B/C-overexpressing neuroblastoma cells with differential MYCN status. Analysing our dataset offers valuable insights into TrkA/B/C receptor signalling in neuroblastoma and its modulation by MYCN status; and holds potential for advancing therapeutic strategies in this challenging childhood cancer.

Orbital Langerhans Cell Histiocytosis: A Systematic Review of 228 Cases.

Orbital Langerhans cell histiocytosis (LCH) is an extremely rare disorder, and widely different manifestations often make it diagnostically challenging. The variability of symptoms - from common presentations, such as eyelid swelling and exophthalmos, to very atypical symptoms, like headaches and diplopia - frequently results in delayed diagnosis and mismanagement. This systematic review aims to describe in detail the clinical presentation, diagnostic approaches, treatment modalities, and outcomes of orbital LCH. This systematic review was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Literature searches were conducted in PubMed and Scopus up to August 2024. Synthesis of data involved 228 patients from 18 studies. Extracted data included study design, sample size, patient demographics (age, gender, ethnicity), clinical presentation, diagnostic criteria, treatment modalities, follow-up duration, recurrence rates, and complications. The review found that orbital LCH mostly affects subjects with a mean age of 8.5 years (SD ± 7.1 years), indicating that a greater number of subjects are from younger populations, with 152 males (66.7%) and 76 females (33.3%). The most common presenting symptom was eyelid swelling, reported in 108 patients (47.4%), often serving as the initial sign prompting further investigation, exophthalmos was observed in 95 patients (41.7%), indicating more significant orbital involvement, and palpable mass was detected in 80 patients (35.1%). Imaging played a critical role in the diagnosis, with CT or MRI revealing lytic lesions in nearly all cases (99%). Histopathology confirmed LCH with CD1a and S-100 proteins serving as hallmark markers of LCH. Treatment strategies for orbital LCH varied depending on the extent of disease, patient characteristics, and institutional practices. Surgical intervention was the most common treatment modality, used in 136 patients (59.6%), and it was very effective in localized disease. Radiation therapy was employed in 68 patients (29.8%), often as an adjunct to surgery or as a primary treatment for residual or inoperable disease. Chemotherapy was administered to 85 patients (37.3%), especially those with multisystem involvement. Observation and follow-up were employed in selected cases, particularly those with solitary or asymptomatic lesions, allowing for the possibility of spontaneous regression. Although the remission rate was high, at 79.8%, there was a recurrence in 14.9% of the patients, thus requiring close follow-up. Diabetes insipidus was a complication, and it was also a pointer to multisystem involvement. Orbital LCH is a diagnosis that requires a multidisciplinary approach for accurate diagnosis and effective management, with individualized treatment guided by advanced imaging and molecular markers. Further studies are needed to refine treatment protocols in an attempt to reduce recurrence rates.

Spontaneous regression of a petroclival meningioma: illustrative case.

Spontaneous regression is relatively rare in meningiomas. Since meningiomas are known to have a relationship with sex-related hormones, spontaneous regression cases related to sex hormones have been reported. A 66-year-old man with a petroclival meningioma was radiologically followed up for 13 years. The tumor initially measured 2.535 cm3 and 2.521 cm3 on gadolinium-enhanced magnetic resonance imaging (MRI) and fast imaging employing steady-state acquisition MRI, respectively. However, the measurements decreased in the follow-up period to 0.977 cm3 and 0.98 cm3, respectively, demonstrating spontaneous regression of an asymptomatic meningioma located in a petroclival area. Continuous meticulous long-term follow-up revealed this phenomenon. It is important to retain the option of conservative treatment for patients ineligible for surgery for reasons such as advanced age and coexisting diseases. https://thejns.org/doi/10.3171/CASE24416.

7418 Xanthoma Disseminatum - A Rare cause of Diabetes Insipidus

Abstract Disclosure: P. Balasubramanian: None. J. Cohen: None. Z. Corbin: None. G. Panse: None. S.E. Inzucchi: None. Background: Xanthoma disseminatum is a rare non-Langerhans cell-derived benign histiocytosis of unknown etiology, characterized by mucocutaneous xanthomatosis. Systemic involvement occurs in a subset of patients, the most common manifestation being central diabetes insipidus in the setting of hypothalamic-pituitary- infundibulum infiltration, occurring in about 30-50% of the patients. We present the case of a man with biopsy proven cutaneous xanthoma disseminatum who developed central diabetes insipidus due to pituitary stalk involvement. Case Presentation: A 69-year-old male presented with a 2-year history of symmetrically distributed, erythematous to hyperpigmented macules and papules in the axillae and inguinal folds. He did not have any mucosal lesions. Skin biopsy revealed histiocytic infiltrate consistent with non-Langerhans cell histiocytosis, likely xanthoma disseminatum. He developed symptoms of polyuria and nocturia around the same time of the eruption, resulting in a large daily fluid intake of 100-120 ounces/day for several months. Laboratory evaluation revealed normal electrolytes. After an overnight water deprivation test, serum osmolality was 299mOsm/kg, serum sodium was 144mmol/L and urine osmolality was 280mOsm/kg, consistent with partial central diabetes insipidus. MRI pituitary with and without IV contrast showed thickening and hyperenhancement of the pituitary stalk. Anterior pituitary function was intact except for mild hypogonadotropic hypogonadism. He was started on DDAVP with good response and resolution of symptoms. Conclusion: Xanthoma disseminatum is characterized by extensive mucocutaneous xanthomatosis with occasional systemic involvement. The natural history of xanthoma disseminatum is usually benign, indolent, and slowly progressive with spontaneous regression described in a few cases. Hypothalamic and pituitary involvement may cause hyperprolactinemia, central diabetes insipidus, and variable degrees of hypopituitarism. Diabetes insipidus is often mild and sometimes transient. Occasionally, central diabetes insipidus can precede the skin lesions. Prognosis is generally good. Central nervous system involvement outside the hypothalamus/pituitary carries a poor prognosis. Presentation: 6/2/2024

6925 A Rare Case of Metastatic Papillary Thyroid Carcinoma Confined to Cervical Lymph Node with No Identifiable Primary Tumor In The Thyroid Gland. A Diagnostic Conundrum

Abstract Disclosure: R. Abdelmasih: None. W. Pan: None. Introduction: Papillary thyroid carcinoma (PTC) is the most common treatable thyroid cancer (TC) with very good prognosis. Metastatic PTC either in the lymph node LN or extra-nodal with no primary thyroid lesion identified is a rare phenomenon referred to as occult thyroid carcinoma (OTC). Despite its rarity, it is reported and constitute a diagnostic conundrum. herein we present a case of metastatic PTC identified in cervical lymph nodes (LN) without a primary tumor in the thyroid gland confirmed with surgical pathology. Case Presentation: A 43-year-old female with history of post-ablative hypothyroidism after treatment of toxic nodular goiter for 10 years, with no family history of thyroid cancer presented with incidentally found left 1.8 Heterogeneous hypoechoic solid nodule with lobulated borders and internal calcifications along with left-sided 0.8 LN without normal fatty hilum on Ultrasound Head and Neck. Fine needle aspiration of the left thyroid nodule and suspicious LN revealed PTC in the left LN though the thyroid nodule sample was non-diagnostic. CT of head and neck showed partially calcified thyroid nodule, Hyperattenuating 8 mm left III LN without fatty hilum, and 9 mm left II calcified LN. Patient underwent total thyroidectomy, central neck, and left lateral neck dissection. Surgical pathology showed no malignancy in thyroid gland or central LNs and 1 out 5 LN of the left neck dissection showed PTC with tumor grading of pT0 pN1b pMNA. patient underwent whole-body thyrogen-stimulated thyroid scan which showed iodine avid tissue in the thyroid bed followed by high-dose I-131 radioactive iodine ablation (RAI). Discussion: OTC refers to impalpable incidental TC less than 10 mm per the WHO. Boucek et al classify OTC into four categories, recently a fifth category was added, in which metastasis is confirmed either in regional LN or distant metastasis though thyroid tissue is confirmed to be benign per pathology and imaging evaluation, our patient falls in the fifth category. Hypothesis of this phenomenon is not well understood, one suggested explanation is missed diagnosis due to not enough sample or if lesion is less than 3 mm. another hypothesis is tumor spontaneous regression, or regression secondary to treatment that was inadequate to treat the systemic process of the tumor, which we believe our patient fits in this hypothesis, given that she underwent RAI ablation many years ago. Tumor regression is very rare and reported to be 1 in 140,000 cases. Another theory suggests that PTC can arise in ectopic thyroid tissue. This case is to shed light on a rare clinical and pathological entity to avoid missed diagnoses. Prognosis depends on the extent of metastasis, with favorable one when it is limited to regional LN and worse with distant metastasis. More cases reports are warranted to help guide further management of such cases due to the lack of available guidance in use of RAI surveillance and ablation. Presentation: 6/1/2024

6823 A Puzzling Case: Complete Regression of Pituitary Macroadenoma

Abstract Disclosure: N.T. Mazengia: None. D.R. Vangipuram: None. S.K. Majumdar: None. Introduction: The natural course of nonfunctioning pituitary macroadenomas remains poorly understood, largely because the majority are surgically treated [1]. There are a few case reports describing the spontaneous regression of nonfunctioning pituitary macroadenomas. Here we describe a case of pituitary macroadenoma which completely regressed following childbirth and two months of cabergoline therapy. Case Presentation: A 25-year-old female presented with bilateral nipple discharge and persistently elevated prolactin levels ranging from 31µg/liter to 45.9 µg/liter (NV &amp;lt;25 µg/L). She did not have any signs and symptoms of hypo or hypersecretion of the pituitary hormones. All her pituitary hormone levels were within normal range. Initial MRI revealed a pituitary mass measuring 9x13x9mm (AP, TR, CC). Given her lack of symptoms, the decision was made to follow up without any intervention. A repeat MRI after one year showed the size of the mass to be 11x13x11mm. Two years after her initial diagnosis, the patient had a spontaneous pregnancy, during which she remained asymptomatic with normal pituitary hormone levels. She had Cesarean delivery at term with no complication. She was lost to follow-up for about two years after childbirth then presented with breast discomfort and galactorrhea at which time, she was started on cabergoline. A subsequent MRI done two months after the start of cabergoline showed asymmetric fullness of the pituitary gland on the right with no discrete measurable lesion. Conclusion: We currently lack a comprehensive explanation for the regression observed in our patient. Silent ischemia may have played a role, particularly considering the natural increase in pituitary gland size during pregnancy. We are not sure if the regression can be solely attributed to the two months of cabergoline treatment. In asymptomatic patients diagnosed with nonfunctioning pituitary macroadenoma, tumor regression can potentially occur through either a "wait and watch" strategy or medical management using dopamine agonists, specifically cabergoline. However, the use of cabergoline as a primary treatment for asymptomatic nonfunctioning pituitary adenoma warrants further investigation. This is especially crucial given that, in most cases, nonfunctioning pituitary macroadenomas tend to increase in size during follow-up without any intervention.

7102 Pituitary Apoplexy with Eventual Complete Tumour Involution

Abstract Disclosure: A. Ng: None. R. Lai: None. Pituitary apoplexy is an endocrinological emergency resulting from infarction or haemorrhage of the pituitary gland. We present a case of pituitary apoplexy from a non-functioning pituitary macroadenoma, complicated by pituitary insufficiency and subsequent tumour involution. An 80-year-old gentleman presented to the Emergency Department with sudden severe headaches and persistent vomiting and admitted for further evaluation. Computed tomography (CT) imaging of the brain showed a prominent pituitary gland and magnetic resonance imaging (MRI) confirmed a large sellar hyperintense lesion containing blood and proteinaceous material. It measured 1.6 cm by 1.2 cm by 1 cm and indented the optic chiasm. CT angiography did not reveal any aneurysms or intracranial haemorrhage. There were no neurological or visual field deficits at presentation. There was no indication for surgery upon neurosurgical consultation. Initial evaluation of the pituitary axis was consistent with central hypocortisolism (cortisol 75 nmol/L, adrenocorticotropic hormone 1.4 pmol/L [reference range (RR) 1.6-13.9]) and hypoprolactinaemia (prolactin 56 mIU/L, RR 73-351). Luteinising hormone levels were &amp;lt; 1 IU/L (RR 1-9); follicle stimulating hormone levels were 3 IU/L (RR 1-19) and testosterone levels were &amp;lt; 1 nmol/L (RR 5 to 30) as the patient was on androgen deprivation therapy for prostate cancer. Hydrocortisone was started and he was monitored for development of frank diabetes insipidus. He did not require regular desmopressin. He later developed anti-diuretic hormone mediated hyponatraemia (serum sodium nadir of 125 mmol/L, serum osmolality 275 mmol/kg, urine osmolality 390 mmol/kg) that was managed with fluid restriction and solute loading. He also developed central hypothyroidism on day 19 of admission (free thyroxine 11 pmol/L, thyroid stimulating hormone 0.49 mIU/L, RR 0.45-4.5) and oral levothyroxine was started. He was discharged with oral hydrocortisone and levothyroxine replacement. A repeat MRI of the pituitary 2 months later showed complete resolution of the mass and resolution of the mass effects. He was kept on oral hydrocortisone and levothyroxine replacement with regular follow-up.Most pituitary macroadenomas are non-functional, and can present with complications of apoplexy, mass effects or hormonal disturbances. However, the natural history of non-functional macroadenomas is not well known as most are operated on. Spontaneous regression of the tumour can rarely occur, notably in the setting of apoplexy and lymphocytic hypophysitis. Recovery of the pituitary axis may also accompany tumour regression. As spontaneous remission of pituitary macroadenomas may occur, close observation of tumours without visual field defects or significant mass effects may be an alternative to surgery. Presentation: 6/1/2024 12:15:00 PM

The role of cytoreductive nephrectomy in the era of immune checkpoint inhibitors: A review of current evidence and ongoing trials.

Renal cell carcinoma (RCC) was diagnosed in over 400 000 individuals globally in 2020, making it a significant global health concern. The incidence of RCC varies by region and overall mortality rates have been declining. This decline is attributed in part to advancements in early cancer detection through imaging and the development of more effective systemic therapies. Cytoreductive nephrectomy (CN) was adopted as a standard treatment for metastatic RCC (mRCC) based on clinical experience and early clinical trials. However, the treatment landscape has shifted with the introduction of tyrosine kinase inhibitors (TKI) in 2007 and, more recently, immune checkpoint inhibitors (ICIs). Dual ICI therapy and combinations of ICIs with TKIs are collectively referred to as immuno-combination therapies and have become standard first-line treatments. This review examines the evolving role of CN in the era of immuno-combination therapies, with a focus on patient selection and the timing of surgery. The immunogenic nature of RCC, characterized by spontaneous tumor regression and immune cell infiltration, suggests a potential benefit from combining CN with ICI therapy to enhance treatment outcomes. This is supported by several clinical studies that reported improved outcomes; however, these were limited by their retrospective nature. Ongoing clinical trials, such as NORDIC-SUN, PROBE, and SEVURO-CN, are expected to provide critical insights into the role of CN in the ICI era. Their findings will ultimately guide future clinical decision-making and further refine treatment strategies for mRCC.

Investigating the pathophysiology and evolution of internal carotid dissection: a fluid-structure interaction simulation study.

Arterial dissection, a condition marked by the tearing of the carotid artery's inner layers, can result in varied clinical outcomes, including progression, stability, or spontaneous regression. Understanding these outcomes' underlying mechanisms is crucial for enhancing patient care, particularly with the increasing use of computer simulations in medical diagnostics and treatment planning. The aim of this study is to utilize computational analysis of blood flow and vascular wall to: (1) understand the pathophysiology of stroke-like episodes in patients with carotid artery dissection; and (2) assess the effectiveness of this method in predicting the evolution of carotid dissection. Utilizing contrast-enhanced magnetic resonance angiography (MRA), we segmented images of the patient's right internal carotid artery. These images were transformed into 3D solids for simulation in Ansys multifisic software, employing a two-way fluid structure interaction (FSI) analysis. Simulations were conducted across two wall conditions (atherosclerotic and normal) and three pressure states (hypotension, normotension, hypertension). The simulations indicated a significant pressure discrepancy between the true and false lumens of the artery. This suggests that flap motion and functional occlusion under hypertensive conditions could be the cause of the clinical episodes. Thrombotic risk and potential for dissection extension were not found to be critical concerns. However, a non-negligible risk of vessel dilation was assessed, aligning with the patient's clinical follow-up data. This study highlights specific hemodynamic parameters that could elucidate carotid artery dissection's mechanisms, offering a potential predictive tool for assessing dissection progression and informing personalized patient care strategies.