Incidentalomas: Incidentally lifesaving or incidentally burdensome?

Incidentalomas are incidental findings discovered during investigations carried out for an unrelated problem. Particularly with the rising use of imaging modalities such as CT and US in everyday clinical practice, finding additional pathologies is becoming more commonplace. Most frequently these are found in the kidneys, adrenal, thyroid, liver and pituitary gland.1 While it may be thought that ‘knowledge is power’, and that surely it is better to know of such diagnoses rather than miss them, the reality is that not all roads lead to improved patient outcomes. Rather, the discovery and subsequent investigation of benign pathologies places additional burden on an already strained healthcare system, and the further investigations and ongoing monitoring they lead to have potential to cause more harm than good. To gain a more complete understanding of this, adrenal and pituitary incidentalomas are examined in more detail below. Adrenal incidentalomas are common in clinical practice, occurring in 4.2% of radiological studies,2 and are identified in 3–4% of abdominal CT scans.3 Most lesions are benign and non-functioning; however, further evaluation is required before this can be determined.3 Thus, once an adrenal lesion is discovered, the first step is to ascertain whether it is hormonally active and whether it is malignant. Primary adrenal malignancy is rare, occurring in only 0.5–2 per million3; however, of the benign tumours, there is a subset that have a profound clinical impact. Up to 14% of benign lesions are functionally active, secreting cortisol, aldosterone, or occasionally both,4 and causing syndromes including Cushing's and Conn's. Phaeochromocytomas account for 7% of benign, but hormonally active lesions.4 The most common functional pathology arising from hormonally active lesions is mild cortisol excess and, in these cases, care comprises either active surveillance or adrenalectomy.4 Overall, while adrenal incidentalomas are commonly identified, and the majority are benign and non-functional, patients with hormonally active, or malignant lesions will benefit from early detection. Thus, following identification of an adrenal incidentaloma, initial investigation is critical, and it is recommended repeat imaging be performed at 3–6 months, and then every 1–2 years ongoing to monitor growth.3 Pituitary lesions are frequently found by chance and are identified in 10–40% of brain images.1 Small pituitary lesions are present in 20% of individuals, although most do not cause clinical sequelae1; 90% are comprised of Rathke's cleft cysts and pituitary adenomas, the majority of which are small and non-functioning1 Functioning adenomas are usually diagnosed following investigation of associated symptoms. Treatment decisions are based on an array of factors, including but not limited to: tumour size, location, mass effect on surrounding structures, and functional activity. Conservative management is often indicated in the first instance for non-malignant lesions, comprising of periodical MRI monitoring and clinical re-assessment1 Overall, use of modern technology in medicine has precipitated escalating detection of incidental lesions. How this translates to patient outcomes remains less clear. In the rare instance a primary malignancy, or a silent but hormonally active tumour is found, these patients will benefit from early intervention and treatment. However, the opportunity costs of investigating all incidentalomas, the majority of which are inconsequential, is significant, with increasing healthcare resources utilised to investigate and monitor incidental findings. In an era of increasingly defensive medicine, once a lesion is found, it cannot be ignored, thus precipitating a cascade of ongoing tests. This begs the question: in an already strained, overworked, and understaffed healthcare system, is workup and surveillance of benign asymptomatic disease better for our population in the long run? Only time will tell.