Adrenal Cyst
Gross Pathology:
- The present case has a single unilocular cyst with an overall pale brownish appearance. The size of the cyst is approximately 6x5x5 cm with pale, thin brownish fluid-like material. Cyst wall thickness is around 2-3 mm. No solid or necrotic areas are seen.
Histopathology:
- Residual normal adrenal cortical tissue, with areas of fibrous-walled pseudocyst
- The cyst has an irregular flat lining
- Occasional areas show pink fibrinous material inside the capsule cleft.
Practical Points of Pathoclinics:
- Adrenal cysts are very uncommon
- Adrenal cysts are usually unilateral and often present in the middle-old age group and are more common in women
- Most cysts are asymptomatic and present as incidental findings. Adrenal cysts can produce vague pain of variable intensity, probably due to an increase in size or intracystic hemorrhage.
- Adrenal cysts are commonly small and rarely acquire large cysts, containing hemorrhage or fluid and compression of adjacent organs.
- There are four types of adrenal cysts:
- (1) Endothelial cyst: Such type of cyst is usually multi-locular, and probably develop due to the dilation of ectatic vessels and associated hemorrhage. They are lined by flat to cuboidal endothelial cells. Endothelial cells are positive for factor VIII, D2-40, and CD34.
- (2) Pseudocysts: Usually unilocular and lack endothelial or epithelial cell linings with surrounding fibrous capsule, granulation tissue, hemosiderin deposition, calcification, and normal adrenal tissue. Sometimes patchy endothelial lining can be seen, indicating its origin from vascular structures, like endothelial cysts. Pseudocysts usually contain hemorrhagic fibrinous material.
- (3) Parasitic cyst: Echinococcal cyst contains diagnostic laminated membranes and scolices.
- (4) Epithelial cyst: Such cyst is lined by epithelial cells, which are CK positive.The origin of such cysts is related to the mesothelial inclusion cyst, embryonal cysts, and cystic neoplasms.
- In uncommon instances, adrenal cortical adenoma, adrenal cortical carcinoma, pheochromocytoma, and neuroblastoma, can produce cystic mass lesions due to bleeding inside the tumor. Such changes can be extensive, and involve the entire neoplasm, and simulate an adrenal cyst. On pathologic examination, residual normal adrenal tissue within cyst or cyst wall without tumor necrosis and neoplastic cells favor the impression of adrenal cyst rather than adrenal neoplasm.
- Metastatic lesions in the adrenal gland can produce cystic changes with hemorrhage.
- Microcysts in adrenal glands are very common in premature infants, probably related to developmental deviation, infection, and stress.