Clinical care of patients with cyclic Cushing’s syndrome (CS) is challenging. Classical pitfalls include incorrect subtyping, unnecessary surgical procedures and delayed definite treatment. A 43-year-old female suffered from a rapidly cycling ectopic CS. She experienced six cycles of severe hypercortisolism within a 2 year period (maximum plasma cortisol 5316 nmol/L, normal range 124.2–662.4 nmol/L; maximum urinary free cortisol 79,469 nmol/24 h, normal range < 414 nmol/24 h) lasting 2–9 weeks. The episodes were associated with pronounced hypokalemia (lowest K+ value recorded 2.4 mmol/l) and progressive signs and symptoms of CS. A bilateral inferior petrosal sinus sampling (BIPSS) performed during a trough phase was false positive for pituitary ACTH overproduction resulting in unnecessary transsphenoidal surgery while a second BIPSS performed during an active phase was indicative for ectopic CS. The 18F-DOPA PET/CT showed a pancreatic lesion, which was subsequently partially removed. Surprisingly, the histopathology was conclusive for ACTH-positive lymph node metastasis located in the retro-duodenal tissue of an occult neuroendocrine tumor WHO grade II. The primary tumor has not been identified so far and, because of the persistent hypercortisolism, the patient underwent bilateral adrenalectomy. Two years later, ACTH levels started to increase progressively. Percutaneous biopsy of a newly identified suspected lesion in the fifth thoracic vertebra revealed a metastasis with positive staining for ACTH, synaptophysin and chromogranin A. Therapy with carboplatin and etoposide was started and, since then, the patient underwent 12 cycles of chemotherapy. We report the challenging case of a rapidly cycling CS secondary to ACTH-secreting neuroendocrine intestinal tumor of unknown primary. We highlight the importance of performing diagnostic tests only during the phases of active cortisol secretion and as soon as first symptoms appear to avoid pitfalls.

中文翻译：

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循环性库欣综合征中双侧下颌窦窦取样的陷阱

患有周期性库欣综合征（CS）的患者的临床护理具有挑战性。传统的陷阱包括错误的分型，不必要的手术程序和延迟的明确治疗。一名43岁的女性患有快速循环的异位CS。她在2年内经历了六个严重的皮质醇过多症周期（最大血浆皮质醇5316 nmol / L，正常范围124.2–662.4 nmol / L；最大尿游离皮质醇79,469 nmol / 24 h，正常范围<414 nmol / 24 h）持续2–9周。发作与明显的低钾血症（记录的最低K +值为2.4 mmol / l）和CS的进行性体征和症状有关。在低谷期进行的双侧下颌窦窦取样（BIPSS）对垂体ACTH过度产生是假阳性，导致不必要的经蝶窦手术，而在活跃期进行的第二次BIPSS则提示异位CS。18F-DOPA PET / CT显示出胰腺病变，随后将其部分切除。令人惊讶的是，组织病理学对于位于隐匿性神经内分泌肿瘤WHO II级的十二指肠后组织中的ACTH阳性淋巴结转移具有决定性意义。到目前为止，尚未发现原发肿瘤，并且由于持续的皮质醇过多症，患者接受了双侧肾上腺切除术。两年后，ACTH水平开始逐渐增加。对第五个胸椎中新发现的可疑病变进行经皮活检，发现转移灶中ACTH，突触素和嗜铬粒蛋白A呈阳性。开始用卡铂和依托泊苷治疗，此后患者接受了12个化疗周期。我们报告具有挑战性的情况下，继发于未知原发性ACTH分泌神经内分泌肠肿瘤的快速循环CS。我们强调仅在活动性皮质醇分泌阶段以及一旦出现第一症状即可避免陷阱的前提下进行诊断测试的重要性。我们报告具有挑战性的情况下，继发于未知原发性ACTH分泌神经内分泌肠肿瘤的快速循环CS。我们强调仅在活动性皮质醇分泌阶段以及一旦出现第一症状即可避免陷阱的前提下进行诊断测试的重要性。我们报告具有挑战性的情况下，继发于未知原发性ACTH分泌神经内分泌肠肿瘤的快速循环CS。我们强调仅在活动性皮质醇分泌阶段以及一旦出现第一症状即可避免陷阱的前提下进行诊断测试的重要性。