This is the last post about adrenal incidentaloma. Here the original text, where everything is better explained, but it'll take you much longer to read.
SURGICAL INDICATIONS
- Every lesion >4 cm with indeterminate image characteristics should be excised because of risk of ACC
- Indeterminate lesions <4 cm should be discussed in MDT (multicisciplinar team) before surgical referral.
- Benign lesions >4 cm should be discussed in MDT before surgical referral, because the larger the image, the higher the ACC risk. There is no diameter cut-point for excision.
- Some clearly benign lesions like myelolipomas or cists may be referred to surgery if they cause compression simtoms or are very large.
- Hypersecreting lesions (PhCC, Cushing, Conn) must be excised.
- Adenomas with Autonomous Cortisol Secretion (ACS) must be discussed in MDT and in some cases surgery can be proposed depending on age, comorbidities, cortisol levels, and patient preferences.
PERIOPERATIVE CARE
- Cushing's patients develop adrenal insufficiency after removal of adenoma, therefore they need peri- and postoperative stress glucocorticoid replacement and long-term therapy until a normal synacthen.
- Pheochromocytoma must be pre-treated with alpha- and sometimes betablockers before surgery. After clamping tumor vascularity fluid and pressors may be needed to avoid hypotension.
- Aldosterone-producing adenoma (APA) removal could lead to normalization of blood pressure, but not always.
SURGICAL TECHNIQUES
- Laparoscopic transperitoneal adrenalectomy is the first-line procedure for benign lesions of small and medium size.
- When open surgery is necessary, anterior, side or posterior approaches are available.
- ACC can be laparoscopically accessed when <6 cm without evidence of extra-adrenal extension. Otherwise open surgery is preferred. When switch from laparoscopic to open surgery is needed, it should be done as soon as possible, before capsule is broken.
- Laparoscopic posterior (retroperitoneoscopic) access has been recently developed. Trauma is smaller, but surgical field is also more restricted.
- Robotic transretroperitoneal laparoscopic approach is possible. Range of motion and vision is better than in traditional surgery, but operative time and learning curves are longer.
NONSURGICAL FOLLOW-UP
- Benign lesions <4 cm should not be followed-up, according to European reccomendations. AACE, however, recommends 5 y surveillance.
- Attitud in benign images >4 cm must be individualized, ideally by MDTs. In younger patients, surgery is generally preferred and surveillance in older. In young patients when surgery is ruled out, MRI image is better to reduce radiation risk.
- Lesions >4 cm with indeterminate image are surgical. If for whatever reason it's not operated, 6-12 month image must be performed, and surgical referral indicated if diameters grow > 5 mm or size >20%. In case of smaller grouth, 6-12 month reassessment is adviced.
- Repeated hormonal testing is not recommended if inicially normal.
- In ACS, although risk of Cushing syndrome is negligible, annual hormonal testing can be performed
FUTURE RESEARCH
Urine steroid metabolomics- 24h urine steroids, including final products (aldosterone, cortisol, androgens) and its precursors can be analyzed using mass spectrometry (MS) using two techniques: Gas chromatography (GC-MS) or liquid chromatography (LC-MS/MS).
- GC has got better resolution but is more cumbersome, therefore it's better for research. LC conversely is easier and more suitable for clinical use.
- Inicially used for diagnosis of congenital metabolic diseases, with the aid of machine learning it can distinguish normal secretion from ACC secretion, because of elevated precursor pattern. ACC have elevated androgen precursor metabolites, sometimes associated to elevated GC or MC precursor metabolites.
- Reaserch to identify patterns that distinguish ACC from ACAs are being developed and LC panels for use in clinical practice are appearing in the near future.
- Aldosterone-Producing Adenomas (APAs) have also been found through metabolomics raised glucocorticoid precursor and cortisol metabolites. That is associated to signs of hypercortisolism in APAs (hyperinsulinism, IR) that resolves after adenomectomy.
Functional imaging of adrenal cortex
- Iodocholesterol scintigraphy has been around since the 1970 using a cholesterol metabolite NP-59. Current SPECT-TC improved imaging has raised interest for this technique, particularly to differenciate APAs from hyperplasia in primary hyperaldosteronism (PHA). The problems are need for prolongued ACTH suppression, several-day imaging and high dose radiation.
- Etomidate, a specific drug for CYP11B enzymes, has been radiolabelled to identify adrenal tissue in PHA. 11C, 18F and 123I have been used as isotopic labels. 123I has also therapeutical potential for ACC, although that requires validation.
Functional imaging of adrenal medulla
- 123I MIBG has been used to identify chromafin imaging for 30 years, but it requires thyroid suppression and a 2-day procedure. Therefore, other tracers have been investigated, like radiolabelled DA, DOPA or ephedrine.
Radiomics
- Research field consisting in extracting quantitative data from radiologic images like intensity, shape or texture.
- It's been used to distinguish PhCC from adenomas in CT-indeterminate lesions, as well as ACC from ACAs.
- Using machine learning, quantified data extracted from texture images outperform experienced radiologist in differenciating benign adenomas from PhCC in indeterminate lesions, but clinical utility is not established.
