SUN-288 Feeling the Heat: A Neuroendocrine Tumor Presenting as “Hot Flashes”

Abstract Disclosure: P. Seepaulsingh: None. J. Shah: None. T. Haynes: None. S.K. Majumdar: None. A. Sideri Gugger: None. Background: Although post-menopausal hot flashes persist in a significant percentage of the population even in the late post-menopause phase, worsening or atypical presentations of flushing warrant further evaluation. We present a case of a postmenopausal woman diagnosed with metastatic neuroendocrine tumor (NET), initially presenting with new and progressively worsening “hot flashes.” Case Presentation: A 70-year-old woman with resistant hypertension, hyperlipidemia, CKD, GERD and diabetes presented for evaluation of “hot flashes”. Last menstrual period was around 55 years of age and hot flashes had subsided within a couple of years. However, for the past 1.5 years prior to presentation she experienced new, painful flushing involving her face, torso, arms, and legs accompanied by fatigue, anxiety/panic attacks, diarrhea and significant unintentional weight loss of 20 pounds. The symptoms, initially attributed to menopause and life stressors, occurred unexpectedly and were occasionally triggered by activity. She reported experiencing approximately five episodes daily. Extensive investigations ruled out pheochromocytoma, thyrotoxicosis, Cushing's syndrome, and hyperaldosteronism. Laboratory tests revealed elevated plasma 5-HIAA (27 ng/mL, <22 ng/ml), gastrin (276 pg/mL, <115 pg/ml), and chromogranin A levels (1,630 ng/mL, <93ng/ml). Despite discontinuing proton pump inhibitors (PPIs), chromogranin A (CgA) remained elevated (483.4 ng/mL) raising suspicion for NET. A Ga68 Dotatate PET/CT scan revealed neuroendocrine tumor with liver metastases. Biopsy established a diagnosis of metastatic well-differentiated neuroendocrine tumor, and somatostatin analog (lanreotide) therapy was initiated, followed by radioactive somatostatin analog (lutetium Lu 177 Dotatate) when there was disease progression. CgA is being monitored as a marker for treatment response. Conclusion: Hot flashes may extend beyond five years post-menopause, but worsening or atypical hot flashes, especially with accompanying symptoms, necessitate additional investigation to exclude underlying conditions. NETs, rare neoplasms from neuroendocrine cells, are classified by location, functionality, and behavior and can be either asymptomatic or present with general symptoms like diarrhea, fatigue, weight loss, and flushing. The vague symptoms frequently lead to diagnostic delays. Biomarkers are essential for diagnosing, prognosing, monitoring, and guiding the treatment of NETs. CgA while limited by low specificity and affected by many common conditions (CKD, PPI use), can be a valuable tool, highlighting its role in the comprehensive management of NETs in some cases. This case underscores the importance of clinician awareness in evaluating atypical hot flashes, which may signal serious health concerns, including NETs, requiring timely and thorough investigation. Presentation: Sunday, July 13, 2025