Adrenal cysts are rare cystic masses that arise from the adrenal gland. They are usually nonfunctional and asymptomatic measuring less than 10 cm. These lesions may occur simultaneously with other adrenal tumors associated with hormonal hypersecretion. Only a few papers describe the association between an adrenal cyst and adrenocortical adenoma.
Adrenal cysts are rare, and intervention is indicated whenever they are large (>5 cm), symptomatic, functional, and potentially malignant. Laparoscopic management of these cysts in the form of either decortication/excision is safe, effective, and minimally invasive, with minimal blood loss and a shorter duration of hospitalization.
Symptoms
Adrenal cysts or Pseudocysts may become massive and may cause symptoms because of the compression of adjacent structures.
- Abdominal pain, Frequently found
- Painful urination with infection
- Middle thoracic pain,
- Nausea, vomiting, constipation, with anorexia.
- Morning stiffness, and multiple joint pain
- Extreme fatigue
- Weight loss and decreased appetite
- Darkening of your skin (hyperpigmentation)
- Low blood pressure, even fainting
- Majority of the cysts range between 5 and 10 cm, but cysts more than 20 cm may occur
- About one-third are discovered incidentally
- FNA recommended for both diagnostic and therapeutic purposes
- Surgery is indicated if fluid is bloody, cystogram is irregular, or pheochromocytoma or malignancy is suspect
Diagnosis
Imaging
- “Adrenal cyst― is a descriptive term, not a pathological diagnosis
- True adrenal cysts
- The majority are endothelial cysts (lymphangiomas)
- Epithelial cysts are exceedingly rare
- Simple, or minimally complex adrenal cyst, thin rim calcification, no enhancement
- Pseudocysts
- Prior hemorrhage inferred
- Non-enhancing, but complex contents and wall calcification
- Relevant history (extra-adrenal malignancy, rapid growth), biochemical evaluation (cortisol, metanephrines): Consider underlying adrenal neoplasm
- Enhancing soft tissue components may suggest adrenal mass hemorrhage and pseudocyst formation
- parasitic (echinococcal) cyst Rare outside endemic areas Typically in the setting of generalized echinococcus
Top Differential Diagnoses
- Adrenal adenoma
- CECT: Enhancing mass without a visible wall or peripheral calcification
- Gastric diverticulum
- Air-, fluid-, or contrast-filled mass with no enhancement of contents
- Adrenal myelolipoma
- Macroscopic fat
- Necrotic adrenal tumor
- Complex wall with heterogeneous contents
- Retroperitoneal bronchogenic cyst
- Specimen is usually hypocellular
- Bloody specimens may be seen in malignancy
- Hemosiderin- or lipid-laden macrophages may be present
- Bloody fluids should be examined carefully to rule out malignancy
- Cortical adenomas can be difficult to differentiate from lipid-laden macrophages in hypocellular specimens
US
Usually thin-walled cystic lesions with anechoic content and posterior beam enhancement. Internal mobile echoes might be seen.
CT
Small adrenal cysts may be difficult to differentiate from adrenal adenomas on unenhanced CT as they may both have densities in the pure fluid range, i.e. -10 to +10. However on post-contrast CT adrenal adenomas tend to enhance, whereas cysts do not 5.
MRI
MRI is commonly reserved for those equivocal cases on CT and confirms fluid within the cyst (bright T2 signal) 6.
Treatment
- No treatment is required usually
- Imaging surveillance was performed, although intensity and length of follow-up were not defined
- Biochemical evaluation (cortisol, metanephrines) routinely performed to exclude underlying adrenal neoplasm
- Surgical resection for complex cyst with enhancing components, or symptomatic cyst
- Complicated cyst has high attenuation, thick enhancing wall, &/or septations
- Surgery may be needed considering the size, shape of the adrenal cyst,
References
