Endocrine Abstracts

Background: ACTH-ectopic syndrome is a rare cause of endogenous hypercortisolism and may pose serious difficulties in topical diagnosis.

Case description: Clinical features of hypercortisolism manifested at the age of 18 years (2012). A year later he was referred to an endocrinologist: ACTH 113 pg/ml (0–46), cortisol in 24-h urine 2915 μg/day (4.3–176), 1 mg DX test cortisol 1020 nmol/l, 8 mg DX test 764 nmol/l, intact pituitary MRI with contrast, abdominal and retroperitoneum contrast-enhanced CT scan revealed no sighs of mass lesion. Chest CT showed nodular formation in the lingual lobe of the left lung and single enlarged paraaorthic lymph node. Octreoscan was negative. Atypical resection of the left lung was performed (07.02.2014), histological and immunohistochemical study showed typical lung carcinoid with negative expression of ACTH. Due to persistence of the symptoms of hypercortisolism in postoperative period, bilateral adrenalectomy was subsequently performed (24.02.2014) with a slight positive clinical effect. In September 2014 therapy with somatostatin analogues (long-acting octreotide 30–40 mg/month) was initiated with a moderate positive effect in ACTH levels, which remained elevated and continued to increase even in the setting of high-dose dexamethasone treatment. In February 2015 MSCT showed bilateral single enlarged hilar lymph nodes, whole-body diffusion MRI showed no signs of an ectopic tumor. In May 2016 we repeated diffusion MRI which revealed fibrous tissue formation in the apex of the left lung with a size of 9x8 mm and enlarged left hilar lymph nodes. The patient was consulted by a surgeon: due to absence of absolute indications surgical treatment was delayed and follow-up examination was recommended in order to specify the nature of the revealed changes. In December 2016 we observed same changes on chest MSCT scan. In May 2017 we conducted PET-CT with ⁶⁸Ga DOTA-TATE in the setting of octreotide withdrawal and observed radiotracer uptake in previously described findings. The same visualization was obtained by performed whole-body scintigraphy with Tc-99 tetracozactide. The patient underwent surgery (left thoracotomy, upper lobectomy, lymphadenectomy from the root of the left lung and mediastinum) with following course of chemotherapy and entered remission in the postoperative period. Histological and immunohistochemical study showed atypical lung carcinoid with ACTH expression and lymph node metastases.

Conclusion: Described case confirms complexity of topical diagnosis in ACTH-ectopic syndrome, leading to substantial delay in surgical treatment.