Small Tumors Research Articles

Proton Therapy in Uveal Melanoma

Background/Objectives: Uveal melanoma is the most common primary intraocular malignancy in adults. Treatment options for localized, early-stage disease include enucleation, brachytherapy, and proton beam therapy. This review aims to evaluate the role of proton therapy in the definitive management of uveal melanoma, focusing on its physics, radiobiology, treatment techniques, and associated outcomes. Methods: This narrative review synthesizes current literature on proton therapy for uveal melanoma, emphasizing case selection, treatment efficacy, and side effects. Results: Proton therapy offers significant advantages for thicker uveal melanomas (over 8 mm) due to its unique physical properties, including a rapid dose fall-off that protects critical structures like the retina and optic nerve. Proton therapy may have benefits in tumor control for ocular melanomas given its increased relative biological effectiveness relative to photon therapy for these typically more radioresistant melanomas. Proton therapy may also hold special value for uveal melanomas in close proximity to the optic nerve, as patients are at high risk of visual toxicities with brachytherapy. The review discusses the efficacy of proton therapy across small, medium, and large tumors, along with strategies for improving patient survival through combined systemic therapy. Additionally, the potential of ocular reirradiation with proton therapy is addressed. Conclusions: Proton therapy is an effective treatment for uveal melanoma. It offers advantages over brachytherapy for large tumors, tumors that are close to the optic nerve or insertion of extra-ocular muscles.

Replication Stress is an Actionable Genetic Vulnerability in Desmoplastic Small Round Cell Tumors.

Desmoplastic small round cell tumor (DSRCT) is an aggressive sarcoma subtype that is driven by the EWS-WT1 chimeric transcription factor. The prognosis for DSRCT is poor, and major advances in treating DSCRT have not occurred for over two decades. To identify effective therapeutic approaches to target DSRCT, we conducted a high-throughput drug sensitivity screen in a DSRCT cell line assessing chemosensitivity profiles for 79 small-molecule inhibitors. DSRCT cells were sensitive to PARP and ATR inhibitors (PARPi, ATRi), as monotherapies and in combination. These effects were recapitulated using multiple clinical PARPi and ATRi in three biologically distinct, clinically-relevant models of DSRCT, including cell lines, a patient-derived xenograft (PDX)-derived organoid model, and a cell line-derived xenograft mouse model. Mechanistically, exposure to a combination of PARPi and ATRi caused increased DNA damage, G2/M checkpoint activation, micronuclei accumulation, replication stress, and R-loop formation. EWS-WT1 silencing abrogated these phenotypes and was epistatic with exogenous expression of the R-loop resolution enzyme RNase H1 in reversing the sensitivity to PARPi and ATRi monotherapies. The combination of PARPi and ATRi also induced EWS-WT1-dependent cell-autonomous activation of the cGAS/STING innate immune pathway and cell surface expression of PD-L1. Taken together, these findings point towards a role for EWS-WT1 in generating R-loop-dependent replication stress that leads to a targetable vulnerability, providing a rationale for the clinical assessment of PARPi and ATRi in DSRCT.

P3.06D.13 Patterns of Tissue NGS Alterations are Associated with ctDNA Shedding in Non Small Cell Lung Cancer Tumors Harboring EGFR Mutations

P3.06D.13 Patterns of Tissue NGS Alterations are Associated with ctDNA Shedding in Non Small Cell Lung Cancer Tumors Harboring EGFR Mutations

Unusual Presentation: Nephroblastoma/Wilms tumor in an Adult – A Case Report

Abstract Introduction/Objective Nephroblastoma/Wilms tumor is a common renal tumor primarily observed in children, and its occurrence in adults is exceedingly rare. This rarity contributes to the diagnostic challenges encountered in adults. Here, we present a case of a 32-year-old male diagnosed with biphasic nephroblastoma/Wilms tumor in the kidney, with liver and lung metastases. Methods/Case Report A 32-year-old male, without significant past medical history, presented with the chief complaint of abdominal pain for 2-3 weeks. Imaging studies revealed a substantial 17.5 cm kidney lesion accompanied by numerous lung and liver lesions. A liver biopsy indicated a small blue cell tumor, morphologically and immunophenotypically, (positive WT1) resembling nephroblastoma, with a strong suspicion of metastasis. Subsequent kidney biopsy confirmed a small blue cell malignant tumor demonstrating biphasic features, including blastema and epithelial components forming tubular structures similar to the liver biopsy, predominantly showing the blastemal component. The renal tumor biopsy supported the diagnosis of nephroblastoma. Despite chemotherapy, the patient passed away two months after the initial liver tumor biopsy. Results (if a Case Study enter NA) NA Conclusion Diagnosing nephroblastoma in adults poses significant challenges, particularly when initial presentations involve metastases. The occurrence of pediatric tumors in adulthood, though rare, should be considered in the diagnostic process after exhausting other possibilities. It is also important to note that the clinical presentation of pediatric tumors in adults may deviate from typical patterns. While Wilm’s tumor commonly presents as a painless, palpable abdominal mass in pediatric cases, adults may exhibit abdominal pain as the predominant symptom, as present in our case.

Puffed-Cheek CT Improved Evaluation of Buccal Mucosal Neoplasm in Contest to Conventional CT Scan

Background: Oral cancer is a frequent cancer in our country, most people are affected by this cancer are older age. Accurate evaluation of this cancer difficult due to close proximity of bones and soft tissue. So for improve diagnostic accuracy Puffed cheek maneuver should be used with traditional Multidetector Computed Tomography (MDCT).Objective: To determine the improved diagnostic accuracy of Puffed cheek Computed Tomography (PCCT) in evaluation of buccal mucosa tumors in contest to non puffed cheek Computed Tomography.Materials and Methods: This descriptive cross sectional study was carried out in Radiology and Imaging department of Khwaja Yunus Ali Medical College and Hospital from 2022(January) to 2023(July). Cases were referred from different department. After meeting the inclusion criteria patients were subjected for CT scan. Imaging was performed from paranasal sinus and neck region with axial sections from pituitary fossa to arch of aorta, after injection of intravenous iodinated contrast media, multiplanar sagittal, coronal reformation images were obtained. Puffed cheek manoeuvre was performed to separate gingival and oral buccal mucosa in all the cases for improved detailed evaluation. The CT result were then compared with non puffed cheek scans results. Results: Among 30 patients 7 cases were missed by conventional CT scan, thirteen patients showed a mass in the oral cavity that were inseparable from 2 mucosal surfaces. Puffed-cheek images clearly showed the mass and surface of tumor involvement. Other 10 patients in conventional CT showed mass in the margins of tongue, oral cavity but extension and infiltration of surrounding structures by the lesion could not be well delineated, puffed-cheek images clearly showed the specific location, extension, adjacent muscles and other structures infiltration. Conclusion: Puffed cheek CT gives better performance to diagnosis the small buccal mucosal tumors, any irregularity, thickening, more detailing of mucosal surface of oral cavity than conventional CT scan, so can helps in choosing the management & surgical approach also. KYAMC Journal Volume: 15, No: 01, April 2024: 29-32.

De-Escalating Treatment Strategies for Patients with Human Epidermal Growth Factor Receptor-2 (HER2)-Positive Early-Stage Breast Cancer.

Almost one-fifth of breast cancer cases express Human Epidermal Growth Factor-2 (HER2), and such expression is associated with highly proliferative tumors and poor prognosis. The introduction of anti-HER2 therapies has dramatically changed the natural course of this aggressive subtype of breast cancer. However, anti-HER2 therapy can be associated with substantial toxicities, mostly cardiac, and high cost. Over the past few years, there has been growing interest in de-escalation of anti-HER2 therapies to minimize adverse events and healthcare costs, while maintaining the efficacy of treatment. Data from clinical observations and single-arm studies have eluted to the minimal impact of anti-HER2 therapy in low-risk patients, like those with node-negative and small tumors. Though single-arm, the APT trial, in which patients with node-negative, small tumors received single-agent paclitaxel for 12 cycles plus trastuzumab for 1 year, was a practice-changing study. Several other recently published studies, like the PERSEPHONE trial, have shown more convincing data that 6 months of trastuzumab is not inferior to 12 months, in terms of disease-free survival (DFS), suggesting that de-escalating strategies with shorter treatment may be appropriate for some low-risk patients. Other de-escalating strategies involved an adaptive, response-directed approach, and personalized therapy that depends on tumor genomic profiling.

Minimally Invasive Enucleation of Esophageal Leiomyoma: Experience From a Single Institution.

Esophageal leiomyoma is a rare disease, most of which are benign, and endoscopic tumor removal surgery is a widely accepted treatment method. The two surgical approaches, laparoscopic andthoracoscopic,must be selectedand applied according to the tumor size and location. The study aimed to evaluate the results, feasibility, and appropriate approach of minimally invasive surgery to treat esophageal leiomyoma. Subjects and research methods: A retrospective study of 27 cases of patients who underwent endoscopic tumor removal surgery to treat esophageal leiomyoma at Cho Ray Hospital was conducted from January 2015 to April 2020. Demographic characteristics, clinical symptoms, surgical characteristics, and postoperative complications were recorded. A total of16 men and 11 women were included in the study, with an average age of 47.2 years (25-76 years). In total, 92.6% of patients had symptoms, the most common beingdysphagia (n = 19); however, 7.4% of patients still had no symptoms. Tumor removal through right thoracoscopic surgery was performed in 18 patients; the remaining nine patients were approached through laparoscopic intra-abdominal surgery. The median tumor size in all patients is 3.0 cm (2.0-5.0 cm), with the smallest tumor being 1.2 cm and the largest tumor being 8 cm.Postoperative histopathology shows esophageal leiomyoma in 100% of cases. Three cases (11.1%) of esophageal mucosal perforation and one case (3.7%) of tracheal perforation occurred during surgery. There was no case of death or suture leak after surgery. There was one case of postoperative gastroesophageal reflux that was treated successfully with medical treatment for two weeks. The average follow-up period was 21.4 months, with no deaths or recurrences during follow-up. Endoscopic surgery is a safe, minimally invasive method for esophageal leiomyoma removal, with laparoscopy used for tumors near the gastroesophageal junction and right thoracoscopic surgery for remaining tumors, ensuring quick patient recovery.

Current Management of Head and Neck Paragangliomas: A Multicenter Series With Long-Term Follow-Up.

To improve our knowledge about head and neck paragangliomas (HN-PGL), the clinical characteristics of all the patients with HN-PGL included in the Spanish Registry were analyzed, as well as the treatment modalities and their outcomes. A total of 202 patients, 67.8% women, aged 53.1 ± 17.4, with 264 HN-PGL, from 16 Spanish hospitals, were included. Tumors were located in the carotid body in 61%, jugular bulb in 20.5%, tympanic area in 10.2%, and along the vagal nerve in 6.4%. Multiple tumors developed in 20.8% and metastatic disease in 4%. A genetic study was done in 64.4% and showed a pathogenic variant in SDHx in 50%. These patients were younger, with no sex predominance, and had more multiple and metastatic tumors. Tumors were treated by surgery in 134 patients, radiotherapy in 33, and other treatments in 20, and were observed without active treatment in 41 patients, who were older, more often asymptomatic, and had smaller tumors. Tumors treated with radiotherapy were larger and more often in locations other than the carotid body. After a median follow-up of 80 months (interquartile range: 41-136), 6.9% had died; among the survivors, 48.4% were disease-free, 42.1% stable, and 9.4% had progressed. The rate of sequelae was similar among patients submitted to surgery, radiotherapy, or observation. We could not identify any prognostic factor for progression. Most HN-PGL are localized slow-growing tumors. Long-term survival is high, even in case of metastasis. Although surgery is the most common treatment, radiotherapy and active surveillance are safe approaches.

Rare findings of capsule endoscopy. Clinical observation

The article provides a brief overview of the frequency, prevalence of use, and results of video capsule endoscopy in patients with various indications after undergoing CT/MRI enterography or barium sulfate enterography. A clinical case is presented where a patient with symptoms of gastrointestinal bleeding underwent video capsule endoscopy, revealing a small bowel tumor, followed by surgical treatment. This non-invasive technique enables obtaining more accurate data for decision-making regarding further treatment strategies.

Clinical efficacy analysis of endoscopic band electrocision ligation surgical method in the treatment of small submucosal tumors of the gastric fundus

Background The aim of this study was to compare and analyze the clinical effects of endoscopic submucosal dissection (ESD) and endoscopic band electrocision ligation (EEL) in the removal of gastric submucosal tumors (SMTs). Method We analyzed the clinical data of 130 patients with gastrointestinal SMTs (diameter ≤10 mm) who underwent endoscopic resection, including 62 cases in the EEL group and 68 in the ESD group, and compared indicators such as surgical time, intraoperative and postoperative complications, postoperative hospital stay, and surgical cost, between the EEL and ESD group. Results EEL surgery time (8.9 ± 1.1 min) was significantly shorter than the ESD group (62.3 ± 2.8 min) (p < .05), EEL surgery cost (5126.8 ± 26.5 yuan) was significantly lower than the ESD group (15721.3 ± 39.6 yuan) (p < .05), and intraoperative blood loss was also markedly lower in the EEL group (5.6 ± 1.7 ml) compared to the ESD group (42.3 ± 3.5 ml) (p < .05). There was no statistically significant difference in postoperative hospitalization time or postoperative complication incidence between the two groups (p > .05). Conclusions In treating gastric muscular, mucosal, or submucosal tumors with a diameter of less than 10 mm, the EEL surgical method was superior to the ESD surgical method in terms of surgical time, intraoperative blood loss, and cost. There was no difference in hospital stay and postoperative complication rate between the two methods, which was worthy of clinical application.

Desmoplastic Small Round Cell Tumor of the Spinal Canal: A Rare Presentation in a Female Pediatric Patient

AbstractDesmoplastic small round cell tumor (DSRCT) is a rare and aggressive malignancy primarily affecting young individuals, typically originating in the abdominal cavity. While spinal involvement by DSRCT is exceedingly rare, especially in pediatric patients, recognizing such atypical presentations is crucial for optimal management. Here, we present a case of DSRCT involving the spinal canal in a 3-year-old female child, representing one of the youngest documented instances in the literature. Initial symptoms included weakness, lower limb pain, and urinary incontinence. Magnetic resonance imaging revealed an enhancing soft tissue lesion in the spinal canal, prompting tumor excision and histopathological examination. The tumor exhibited characteristic features of DSRCT, including small round cells within a desmoplastic stroma. Immunohistochemistry confirmed the diagnosis, showing positivity for Wilms tumor 1, epithelial membrane antigen, desmin, and synaptophysin. This case highlights the challenges in diagnosing and managing rare tumors like spinal DSRCT, emphasizing the importance of a comprehensive approach to differential diagnosis and individualized treatment strategies.

Conceptual Study on the Effect of Palasha Gudavarti in Post-operative Pain Management of Anorectal Surgeries

Post-operative pain management is a crucial component of recovery, particularly following anorectal surgeries, where pain can significantly hinder healing. The prevalence of postoperative pain after 24 hours of surgery is 55.3%, after 48 hours is 34.7 % and of moderate to severe post-operative pain is 13 % after 24 hours, and 11.7% after 48 hours1 .Ano rectal pathology amenable to ambulatory surgery includes anal fissures, warts, fistulas, hemorrhoids,abscess and small neoplasms. Quick recovery after ano rectal surgery can be successful only with effective post-operative pain control. Acharya Sushruta recommends the use of Yashtimadhu siddha ghritha application over the operated area2 . Additionally , he advocates the application of shoolahara dravyas and vatahara dravyas processed with ghritha to the surgical site for effective pain relief. Planning a cost effective, reliable, time tested and technically simple management is the need of this modem era. The present study explores the possible analgesic, anti-inflammatory, and wound-healing properties of Palasha Gudavarti, offering an alternative approach to conventional pain management techniques.

Endoscopic ultrasound‐guided tissue acquisition allows a reliable proliferation assessment of small (≤20 mm) pancreatic neuroendocrine tumors

Endoscopic ultrasound‐guided tissue acquisition allows a reliable proliferation assessment of small (≤20 mm) pancreatic neuroendocrine tumors

Evaluation of Two Different Approaches for Selecting Patients for Postoperative Radiotherapy in Deep-Seated High-Grade Soft Tissue Sarcomas in the Extremities and Trunk Wall.

Two national sarcoma centers have had different approaches for selecting patients with grade 2-3 deep-seated soft tissue sarcomas (STS) for postoperative radiotherapy (RT). We evaluated potential differences in local recurrence in patients treated at the two centers. At Sarcoma Center 1 (SC1), RT was the standard treatment for all tumors except certain small tumors excised with a margin wider than 1 cm. Sarcoma Center 2 (SC2) avoided RT for tumors regardless of tumor size if removed with a margin wider than 1 cm and/or a solid barrier. We included 386 patients (SC1/SC2 = 196/190) over 18 years of age diagnosed with a non-metastatic grade 2-3, deep-seated STS of the extremities or trunk wall, who underwent primary surgical treatment (only tumors excised with a negative margin) from 1 January 2000, to 31 December 2016. Kaplan-Meier survival analysis, competing risk analysis, and cause-specific Cox regression were applied. A total of 284 patients received primary RT, 163 (83%) at SC1 and 121 (64%) at SC2 (p < 0.001). The cumulative incidence of local recurrence at five years was 15% (95% CI: 10-19%) at SC1 and 14% (95% CI: 9-19%) at SC2. Multivariate analysis showed no significant differences in local recurrence between the centers. We concluded that when entering all available patients into the analysis using an intention-to-treat principle, a more selective approach to postoperative RT in patients with grade 2-3 deep-seated STS did not lead to a higher local recurrence rate. However, with this study design, we cannot rule out if the local recurrence rate could have been lower if RT was administered to all tumors removed with a margin wider than 1 cm and/or a solid barrier.

Myeloid sarcomas with CBFA2T3 : GLIS2 fusion: clinicopathologic characterization of 4 cases mimicking small round cell tumors.

Acute myeloid leukemia with CBFA2T3::GLIS2 fusion can initially present as extramedullary lesions (myeloid sarcoma), leading to a misdiagnosis of nonhematologic pediatric solid tumors. We characterized the clinicopathologic features of 4 cases of CBFA2T3::GLIS2 fusion-positive myeloid sarcoma in pediatric patients where the sarcoma presented either without leukemic involvement (isolated myeloid sarcoma; 3/4 [75%]) or had concurrent leukemic disease (1/4 [25%]). All cases mimicked nonhematopoietic tumors at morphologic and immunophenotypic levels, so the initial evaluation did not raise suspicion for acute myeloid leukemia/myeloid sarcoma. After extensive workup, however, including molecular studies, the diagnosis of myeloid sarcoma with CBFA2T3::GLIS2 fusion was rendered. This study highlights the need for a high suspicion index of GLIS2-rearranged myeloid sarcoma in the differential diagnosis of pediatric small round cell tumors in tissue biopsies and the application of adequate workup to avoid misdiagnosing this entity.

Correlation between White Globe Appearance and Clinicopathologic Characteristics in Early Gastric Cancer.

Magnifying endoscopy with narrow-band imaging (ME-NBI) enables the visualization of detailed microsurface (MS) and microvascular (MV) structures in the gastrointestinal tract. White globe appearance (WGA) is a small whitish lesion with a globular shape identified during ME-NBI for early gastric cancer (EGC). This study aimed to investigate the associations between WGA, clinicopathological characteristics, and other ME-NBI findings in patients with EGC. The presence or absence of WGA in 122 patients (126 lesions) with an endoscopic diagnosis of EGC who underwent ME-NBI before endoscopic or surgical resection was prospectively collected and retrospectively analyzed. During ME-NBI, the MS and MV patterns and the presence of WGA and white opaque substances (WOS) were investigated. EGC cases were categorized as differentiated or undifferentiated type, and mucosal, submucosal, or advanced. Of 126 lesions, WGA was observed in 25 (19.8%). WGA was associated with tumor size (≤2 cm [17/63, 27.0%] vs >2 cm [8/63, 12.7%]; p=0.044), histologic type (differentiated type [22/89, 24.7%] vs undifferentiated type [3/37. 8.1%]; p=0.033), and tumor location (upper third [1/11, 9.1%] vs middle third [18/58, 31.0%] and lower third [6/57, 10.5%]; p=0.017). Although WGA was observed more frequently in lesions with an oval/tubular MS pattern, a fine-network MV pattern, and the absence of WOS, the difference was not statistically significant (MS pattern, p=0.358; MV pattern, p=0.212; WOS, p=0.121, respectively). WGA was associated with small tumor size, differentiated-type histology, and middle-third tumor location, and was more frequently observed in lesions with an oval/tubular MS and fine-network MV patterns and the absence of WOS.

Evaluating Endoscopic Ultrasound-Guided Tissue Acquisition for the Diagnosis of Small Pancreatic Neuroendocrine Neoplasms

Objectives: Although small hypervascular tumors are suspected to be pancreatic neuroendocrine tumors (p-NENs), their diagnosis and treatment are challenging. This study evaluates the usefulness of endoscopic ultrasound-guided tissue acquisition (EUS-TA) for the diagnosis of small p-NENs. Methods: All p-NEN lesions that underwent EUS-TA at our hospital between April 2018 and December 2023 were retrospectively analyzed. The diagnostic sensitivity of EUS-TA and the concordance rate of grading with EUS-TA and surgical specimens were examined. The lesions were grouped by size. Results: The diagnostic sensitivity of EUS-TA was analyzed for 82 lesions, of which 44 were compared with postoperative specimens for grading. The definitive diagnosis was neuroendocrine tumor (NET) in 75 lesions, neuroendocrine carcinoma in five lesions, and mixed neuroendocrine non-neuroendocrine neoplasm in two lesions. Thirty tumors were ≤ 10 mm, 30 were 10–20 mm, and 22 were &gt; 20 mm, and the diagnostic sensitivities were 96.7%, 96.7%, and 90.9%, respectively. The concordance rates for grading were 94.4%, 82.4%, and 77.8% for tumors ≤ 10 mm, 10–20 mm, and ≥ 20 mm, respectively, with Cohen’s kappa coefficients of 0.64, 0.48, and 0.40, respectively. Conclusions: EUS-TA showed adequate diagnostic sensitivity and grading agreement for p-NENs of all sizes, allowing for the determination of the appropriate treatment.

Diagnostic Value of Contrast-Enhanced Dual-Energy Computed Tomography in the Pancreatic Parenchymal and Delayed Phases for Pancreatic Cancer.

Background/Objectives: The usefulness of dual-energy computed tomography (DECT) for low absorption in the parenchymal phase and contrast effects in the delayed phase for pancreatic cancer is not clear. Therefore, the diagnostic capability of low-KeV images obtained using DECT for pancreatic cancer in the pancreatic parenchymal and delayed phases was evaluated quantitatively and qualitatively. Methods: Twenty-five patients with pancreatic cancer who underwent contrast-enhanced DECT were included. A total of 50 and 70 KeV CT images, classified as low-keV and conventional CT-equivalent images, were produced, respectively. The tumor-to-pancreas contrast (Hounsfield units [HU]) in the pancreatic parenchymal and delayed phases was calculated by subtracting the CT value of the pancreatic tumor from that of normal parenchyma. Results: The median tumor-to-pancreas contrast on 50 KeV CT in the pancreatic parenchymal phase (133 HU) was higher than that on conventional CT (68 HU) (p < 0.001). The median tumor-to-pancreas contrast in the delayed phase was -28 HU for 50 KeV CT and -9 HU for conventional CT (p = 0.545). For tumors < 20 mm, the tumor-to-pancreas contrast of 50 KeV CT (-39 HU) had a significantly clearer contrast effect than that of conventional CT (-16.5 HU), even in the delayed phase (p = 0.034). Conclusions: These 50 KeV CT images may clarify the low-absorption areas of pancreatic cancer in the pancreatic parenchymal phase. A good contrast effect was observed in small pancreatic cancers on 50 KeV delayed-phase images, suggesting that DECT is useful for the visualization of early pancreatic cancer with a small tumor diameter.

7778 Factors Predicting Recovery of Hypogonadism in Men with Prolactinoma Treated with Dopamine Agonists

Abstract Disclosure: S. Constantinescu: None. O. Alexopoulou: None. D.M. Maiter: None. Introduction: Recovery of hypogonadism is an important objective of dopamine agonist (DA) treatment in men with prolactinoma. However, the extent, timeline, and predictive factors of gonadotrope axis recovery are still unclear. Methods: We report data from a large cohort of 89 men with prolactinoma, looking at the evolution of testosterone levels after 6 and 12 months of treatment with DA. We excluded patients with peripheral hypogonadism, surgical treatment performed less than 12 months after onset of DA treatment, and patients with small tumors (≤ 5 mm and prolactin ≤ 50 µg/l) who did not achieve tumor shrinkage during treatment. We defined low testosterone as a morning value &amp;lt; 10 nmol/l. Patients who had started testosterone supplementation were considered as having persistent hypogonadism. Results: Among the 89 men (mean age ± SD: 44 ± 14 years; 65/89 with a macroprolactinoma), 14 (16%) had normal initial testosterone levels (NT) and 75 (84%) had low testosterone at diagnosis (LT). Compared to LT, NT patients had significantly lower PRL (median 53 µg/l versus 490 µg/l, p=0.009) and smaller tumors (median 6.5 mm versus 21.2 mm, p=0.013). In the NT group, after 6 (n=11) and 12 months (n=10), testosterone rose from a median of 13.4 to 16.6 (p=0.266) and 17.9 nmol/l (p=0.012), respectively. In LT patients, after 6 (n=56) and 12 months (n=42), testosterone rose significantly from a median of 5.8 to 10.7 (p&amp;lt;0.001) and 12.5 nmol/l (p&amp;lt;0.001).In the LT group, 45% (32/71) had recovered eugonadism at 6 months and 57% (40/70) at 12 months. These proportions rose to 61% (22/36) and 67% (n=26/39) at 6 and 12 months when prolactin concentrations were normalized. Factors associated with persistent hypogonadism after one year were chiasmal compression at diagnosis (p=0.05), cavernous sinus invasion (p=0.042), cystic tumoral component (p=0.038), a greater tumoral diameter (mean 25 mm vs 15 mm, p&amp;lt;0.01), lower testosterone concentrations at diagnosis (mean 3.6 nmol/l vs 6.8 nmol/l, p&amp;lt;0.001) and at 6 months (mean 6.0 nmol/l vs 13.0 nmol/l, p&amp;lt;0.03), and higher prolactin levels at one year (median 17.15 µg/l vs 8.4 µg/l, p=0.064). Testosterone &amp;lt; 6.7 nmol/l at 6 months predicted the long-term persistence of hypogonadism with 72% sensitivity and 92% specificity. Conclusion: The sensitivity of the gonadotrope axis to high prolactin levels is highly variable in men with prolactinoma and 16% of them retain normal testosterone concentrations. However, this finding does not exclude partial inhibition of the gonadotrope axis that will improve with DA treatment. In patients with low testosterone levels, the recovery rate of hypogonadism is 45% at 6 months and 57% at 12 months, increasing to 67% if prolactin is normalized. Testosterone supplementation could be started early in patients with large, invasive, cystic and/or compressive tumors, with a testosterone concentration lower than 6.7 nmol/L after 6 months of treatment. Presentation: 6/3/2024

6637 A Rare Case of a Possible Non-functional (Clinically Silent Biochemically Negative) Adrenal Pheochromocytoma

Abstract Disclosure: V.K. Babu: None. M.T. Corwin: None. S.T. Olatunbosun: None. Introduction: Adrenal pheochromocytomas (pheo) are rare neuroendocrine tumors arising from the chromaffin cells of the adrenal medulla. Their incidence is around 0.8 per 100,000 patient years. They are usually sporadic, with about 40% having a pre-existing familial genetic disease. About 3% of adrenal incidentalomas prove to be pheo. They have a heterogenous presentation and are diagnosed by measuring urinary and plasma fractionated metanephrines (met) and catecholamines (catecho). The diagnosis becomes challenging in patients presenting with small tumors and normal levels of biochemical metabolites, as in our patient. Clinical Case: A 32-year-old male with no significant past medical history was referred to us with a left adrenal incidentaloma of 1.2 cm x 1 cm with 23 Hounsfield units during a non-contrast CT scan performed for abdominal pain. He denied spells of headaches, excessive perspiration, palpitations, history of hypertension, hypokalemia, history of kidney stones, fractures, muscle weakness, easy bruisability, new abdominal striae, change in weight, steroid use, or family history of endocrine tumors. MRI with adrenal protocol 3 months later showed a 1.2 cm x 1.4 cm left adrenal nodule that was markedly hyperintense on T2-weighted and hypointense on T1-weighted images without microscopic fat, suspicious for a pheo. It also demonstrated peripheral enhancement with progressive central filling on the delayed images without washout. Plasma met and catecho were normal: normetanephrines (normet) (45.2 pg/mL), met (36.4 pg/mL), epinephrine (epi) (34 pg/mL), norepinephrine (norepi) (295 pg/mL) and dopamine (&amp;lt;30 pg/mL). Subsequent 24-hour urine testing revealed normal met (155 mcg/day, 154 mcg/day), and normal normet (248 mcg/day, 236 mcg/day) on two separate occasions, and normal epi (9 mcg/L), norepi (36 mcg/day), and dopamine (228 mcg/day). The patient was subsequently referred to Endocrine Surgery for evaluation. Conclusion: Our patient likely has a non-functional pheo. Another possibility is an adrenal hemangioma, which would show discontinuous peripheral nodular enhancement in addition to progressive central filling. Patients with pheo less than 2 cm may present with normal biochemical testing. The size of a pheo is usually proportional to the levels of its biochemical metabolites. This case is unique because patients with a similar sized pheo are expected to have 3 times higher levels of plasma met and catecho, even if still within normal limits. It is important to take tumor size into consideration when interpreting labs to determine its functional status. This may help in determining the need for a pre-operative alpha blockade prior to adrenal surgery. A definitive diagnosis of a pheo’s non-functional status can only be confirmed after histopathological examination of the tumor tissue. Presentation: 6/3/2024