Endocrine Abstracts

Introduction: The incidence of adrenal incidentalomas is 5% among patients undergoing radiological imaging. Differential diagnosis is extremely important, as it determines the tactics of both therapeutic treatment and surgical intervention. Currently, algorithms for the differential diagnosis of adrenal masses have been developed and are widely used. Nevertheless, the compliance with strictly regulated diagnostic protocols does not always allow to make an accurate diagnosis.

Clinical case: A 39-year-old man addressed the clinic with the left adrenal incidentaloma. From the history, it was established that from the age of 35 he had been suffering from arterial hypertension with periodic crises up to 200/100 mm Hg. At 36 he was diagnosed with impaired fasting glucose and therefore started taking Metformin. At 37 chronic glomerulonephritis was detected. In 2018 (at the age of 39) a planned ultrasound of the kidneys revealed a formation in the projection of the upper pole of the left kidney. Contrast CT scan: large left adrenal formation (41×42×56 mm) with fuzzy edges, +33 HU, absolute washout-30%. The patient was referred to an endocrinologist. Objectively: BMI–29 kg/m², BP-160/90 mmHg., heart rate-80 bpm, a single <1 cm-wide purple striae revealed in the right axillary region. 1 mg overnight dexamethasone suppression test was performed: suppression of serum cortisol did not occur: 4.03 μg/dl (<1.8). The level of basal ACTH and the 24-hour urinary fractionated metanephrine (twice) were within normal limits. Based on the results of laboratory examination (twice, normal 24-hour urinary fractionated metanephrine), and the presence of a high-density adrenal mass with delayed contrast, pheochromocytoma was ruled out and glucocorticoid-producing adrenocortical carcinoma was suspected. Laparoscopic left adrenalectomy was performed. According to the results of the histological examination, the removed material corresponded to pheochromocytoma. Due to the apparent discrepancies of the obtained laboratory and instrumental data and morphological findings, the biopsy material was sent to an expert level institution for reassessment, where pheochromocytoma/paraganglioma was confirmed: chromogranin A – strong positive, inhibin, melanA – negative, Ki67<1%. Final diagnosis: left adrenal glucocorticoid-secreting pheochromocytoma. After surgery hemodynamic parameters stabilized, blood glucose level returned to normal.

Conclusion: This case demonstrates that the observance of strictly regulated algorithms of differential diagnosis may not allow making the correct diagnosis. At the preoperative stage, all data had indicated in favor of adrenocortical carcinoma but the immunohistochemical study performed after the operation verified pheochromocytoma. Thus, it is necessary to continue research aimed at improving the diagnostic algorithm.