P-62 Silent Corticotroph Adenoma or Cyclic Cushing's Syndrome?
Authors: Baskurt Ozan , Yılmaz Temel , Yıldırım Hatice , Gazioglu Nurperi 
Published: January 2024

Abstract

Introduction
Silent corticotroph adenomas (pituitary neuroendocrine tumours (PitNET)) are a rare subset of nonfunctioning adenomas. The higher aggressiveness in terms of invasion and recurrence make these tumors dangerous and close follow-up in experienced centers is recommended.

Clinical Case
A 21-year-old obeseo (Body Mass Index:31.71) male patient unable to lose weight and complaining of headaches was referred to the Department of Neurosurgery for a pituitary macroadenoma. He had previously used liraglutide treatment Many purple striae were also seen on the body of the patient, who stated that his wounds did not heal easily. Visual acuity and visual field were normal. There was no neurodeficiency. Endocrinological evaluation revealed that the tumor was nonfunctioning (Table 1). Magnetic resonance imaging of the pituitary gland showed a mass lesion in the right side of the pituitary gland extending to the suprasellar and parasellar area (Knosp grade II) (Fig.1). The tumor with soft consistency was totally removed by endoscopic binostril transsphenoidal approach. The postoperative cortisol was 11.53 µg/dl (6.02-18.4) and free T4 was 1.32 ng/dL (0.93-1.7). The patient had a transient diabetes insipidus in the postoperative course, and he was discharged on the 4th day after surgery. Pathological examination revealed a pituitary adenoma immunostaining diffusely with ACTH, other hormones were unexpressed. Ki-67 was %2. Histological invasion of the dura was noted.
Although the patient was clinically overweight and had purple striae suggestive of Cushing's syndrome (CS), his cortisol and ACTH levels were normal and suppressible with 1 mg dexamethasone suppression test. However, his tumour tissue showed diffuse ACTH expression, which led to the diagnosis of a silent ACTH adenoma. Since the clinical findings were not completely silent, could we assume that he suffered from cyclic CS?
Cyclic (intermittent or periodic) CS is a condition characterised by alternating periods of transiently elevated cortisol levels followed by normal to reduced levels. The diagnosis of cyclic CS requires the presence of at least three confirmed episodes of elevated cortisol levels interspersed with two periods of normal cortisol levels. As we know, the cortisol secretion cycle is unpredictable and laboratory tests during the normal cortisol secretion period of the cyclic CS often show negative results as in our patient.

Conclusion
Postoperative follow-up of a silent corticotroph PitNET and cyclic CS patient, both of whom require close and life-long monitoring.Figure 1.Magnetic resonance imaging of the pituitary gland; coronal sections T1- weighted (a), T2-weighted (b), sagittal (c), and coronal (d) sections with T1 contrast enhancement. The mass lesion on the right side of the pituitary gland extending superiorly to the right internal carotid artery contains a hemorrhagic fluid component with heterogeneous contrast enhancement, is 16*12*9 mm in size, and corresponds to a hemorrhagic pituitary macroadenoma. Table 1.Hormonal values at presentationACTH, adrenocorticotropic hormone; DST, dexamethasone suppression test; fT4, free thyroxine; IGF-1, insulin-like growth factor 1; PRL, prolactin; TSH, thyroid-stimulating hormone.