statdx/docs_md/articles/adrenal-cyst_c5d717a3-3d6e-4e86-9efe-1ad0ec14740f.md

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Adrenal Cyst	c5d717a3-3d6e-4e86-9efe-1ad0ec14740f	key value c3463c5c-31d3-4489-bbfe-6b895abdb86d Mitchell Tublin, MD	name slug treeNodeId Genitourinary genitourinary bd0eb4fe-d465-4faa-a3b7-526e8f01802d name slug treeNodeId Diagnosis diagnosis e82a3e55-c0be-4ed1-acd6-b03ae9167c31 name slug treeNodeId Adrenal adrenal d3b85dea-43cb-4be3-b103-902e38d0336e name slug treeNodeId Benign Neoplasms benign-neoplasms eeebc0ba-f71a-4ae6-8daf-525d0d18fa16 name slug treeNodeId Adrenal Cyst adrenal-cyst null	Genitourinary	c0408d4e-b577-4561-89ba-5fd1d7888eaf	14	09/09/21	Adrenal Cyst	Genitourinary, Diagnosis, Adrenal, Benign Neoplasms, Adrenal Cyst	Adrenal Cyst | STATdx	Adrenal Cyst	DX	true	Genitourinary Diagnosis Adrenal Benign Neoplasms Adrenal Cyst

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title: "Adrenal Cyst" docid: "c5d717a3-3d6e-4e86-9efe-1ad0ec14740f" authors:

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• name: "Diagnosis" slug: "diagnosis" treeNodeId: "e82a3e55-c0be-4ed1-acd6-b03ae9167c31"
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• "Genitourinary"
• "Diagnosis"
• "Adrenal"
• "Benign Neoplasms"
• "Adrenal Cyst"

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KEY FACTS

• Imaging

  • "Adrenal cyst" is descriptive term, not pathological diagnosis
  • True adrenal cysts - Majority are endothelial cysts (lymphangiomas) - Epithelial cysts exceedingly rare - Simple, or minimally complex, adrenal cyst, thin rim calcification, no enhancement
  • Pseudocysts - Prior hemorrhage inferred - Nonenhancing but complex contents and wall calcification - Relevant history (extraadrenal 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 setting of generalized echinococcus

• Top Differential Diagnoses

  • Adrenal adenoma - CECT: Enhancing mass without visible wall or peripheral calcifications
  • 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

• Clinical Issues

  • No treatment required usually
  • Imaging surveillance performed, although intensity and length of follow-up not defined
  • Biochemical evaluation (cortisol, metanephrines) routinely performed to exclude underlying adrenal neoplasm
  • Surgical resection for complex cyst with enhancing components, or symptomatic cyst

• Diagnostic Checklist

  • Complicated cyst has high attenuation, thick enhancing wall, &/or septations

TERMINOLOGY

• Definitions

  • "Adrenal cyst" is descriptive term, not pathological diagnosis - Can mean true cyst, pseudocyst, or cystic mass

IMAGING

• General Features

  • Best diagnostic clue

    - Well-defined, nonenhancing, water-density adrenal mass ± calcifications
    

  • Location

    - Suprarenal
    - Unilateral > bilateral (8-10% of cases)
    

  • Size

    - < 5 cm (50%), up to 20 cm
    

• CT Findings

  • NECT

    - Unilocular or multilocular mass
    - Well-defined, round to oval, homogeneous mass usually with water (0 HU) or near-water density
            - Higher- or mixed-attenuation mass (hemorrhage, intracystic debris, crystals)
    - Wall usually very thin
            - ↑ wall thickness, up to 3 mm for complex cysts
    - Calcifications
            - Rim-like or nodular (51-69%)
            - Centrally in intracystic septation (19%)
            - Punctate within intracystic hemorrhage (5%)
    

  • CECT

    - No central enhancement ± wall enhancement
    - Coronal reformats helpful to determine organ of origin if large cyst
    

• MR Findings

  • T1WI

    - Homogeneous, hypointense mass
    - Hyperintense mass (hemorrhage)
    

  • T2WI

    - Hyperintense mass
    

• Ultrasonographic Findings

  • Simple or septated suprarenal cyst
  • Shadowing from calcification
  • Real-time examination helpful to differentiate adrenal cyst from adjacent (renal, pancreatic) cyst

• Imaging Recommendations

  • Best imaging tool

    - CECT or MR; US for confirmation
    

DIFFERENTIAL DIAGNOSIS

• Adrenal Adenoma

  • NECT: Lipid-rich adenoma (< 10 HU) mimics adrenal cyst - Peripheral or septal calcification favors adrenal cyst
  • CECT: Enhancing mass without visible wall or peripheral calcifications - Assess washout kinetics to diagnose lipid-poor adenoma
  • MR: Signal suppression at out-of-phase, chemical-shift imaging
  • US: Solid adrenal lesion

• Gastric Diverticulum

  • May simulate left adrenal cyst
  • Air-, fluid-, or contrast-filled suprarenal mass
  • No enhancement
  • Normal adjacent adrenal gland

• Adrenal Myelolipoma

  • Fat (not fluid) attenuation mass

• Necrotic Adrenal Tumor

  • Primary (pheochromocytoma or carcinoma) or metastatic - Clinical history, biochemical evaluation, lesion complexity suggest correct diagnosis - Enhancing soft tissue components

• Retroperitoneal Bronchogenic Cyst

  • Rare, benign, suprarenal fluid or soft tissue attenuation lesion
  • Adjacent to but separate from adrenal gland

• Renal Cyst

  • Coronal MR/CT or US useful to determine organ of origin of large, retroperitoneal cystic lesions

PATHOLOGY

• General Features

  • Etiology

    - Congenital (endothelial, epithelial) cysts
    - Acquired (post hemorrhagic, inflammatory) pseudocysts
    - Cystic, hemorrhagic degeneration of underlying adrenal neoplasm
    

• Staging, Grading, & Classification

  • Accepted classification scheme - Pseudocyst - Most common type of cystic adrenal lesion in surgical series - No epithelial or endothelial lining: Fibrous cyst wall - Potentially as complication of prior trauma or hemorrhage though history of such often not elicited - May be associated with underlying adrenal neoplasm (pheochromocytoma, adrenal carcinoma, myelolipoma) - Attenuation and complexity at imaging varies depending upon hemorrhagic component - Wall and septal calcification common - Endothelial cyst - Subtypes: Lymphangiomatous and hemangiomatous - True cyst: Endothelial lining - Originate from preexisting vascular malformation or obstructed, ectatic lymphatic channels - Thin rim calcification typical - Epithelial cyst - Extremely rare: No acinar structures within normal adrenal gland - Mesothelial origin suggested (mesothelial cells potentially incorporated within adrenal gland during embryogenesis) - Parasitic (hydatid) cyst

CLINICAL ISSUES

• Presentation

  • Most common signs/symptoms

    - Typically asymptomatic
    - Larger cysts may be symptomatic
            - Abdominal pain
            - Hemorrhage
    - Clinical history (malignancy, hypertension) elicited
            - May indicate cystic degeneration of underlying adrenal neoplasm (e.g., metastasis, pheochromocytoma)
    

  • Diagnosis - Usually incidental finding at imaging - Endocrine-biochemical evaluation performed to exclude underlying functional adrenal tumor

• Demographics

  • Age

    - Any, though patients 20-50 years of age most common
    

  • Sex

    - M:F = 1:3
    

  • Epidemiology

    - Uncommon entity: Autopsy incidence 0.064-0.18%
    - Accounts for 1% of incidental adrenal lesions in large imaging series
    

• Natural History & Prognosis

  • Complications - Hypertension, infection, rupture, hemorrhage
  • Excellent prognosis for vast majority of incidental, benign adrenal cysts
  • Prognosis for pseudocysts secondary to adrenal neoplasm depends upon tumor histology

• Treatment

  • No treatment required usually - Imaging follow-up typically performed - Intensity and length of surveillance not defined - Cysts may enlarge over time - Endocrine evaluation (cortisol, metanephrine, etc.) performed
  • Surgical resection if symptomatic, underlying adrenal neoplasm - Laparoscopic resection preferred

DIAGNOSTIC CHECKLIST

• Consider

  • Complicated cyst may suggest underlying adrenal neoplasm
  • Clinical history, biochemical evaluation, and prior imaging helpful

• Image Interpretation Pearls

  • Simple adrenal cyst: Scant septation, no enhancement, thin rim calcification - Likely benign endothelial cyst or pseudocyst
  • Coronal imaging helpful to determine organ of origin (and exclude exophytic renal or pancreatic cyst)
  • Complicated cyst: High attenuation, thick enhancing wall, &/or septations - Complexity may suggest underlying adrenal neoplasm and secondary pseudocyst

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References

Selected References

1. Wang F et al: CT and MRI of adrenal gland pathologies. Quant Imaging Med Surg. 8(8):853-75, 2018
2. Lattin GE Jr et al: From the radiologic pathology archives: adrenal tumors and tumor-like conditions in the adult: radiologic-pathologic correlation. Radiographics. 34(3):805-29, 2014
3. Kyoda Y et al: Adrenal hemorrhagic pseudocyst as the differential diagnosis of pheochromocytoma--a review of the clinical features in cases with radiographically diagnosed pheochromocytoma. J Endocrinol Invest. 36(9):707-11, 2013
4. Ricci Z et al: Adrenal cysts: natural history by long-term imaging follow-up. AJR Am J Roentgenol. 201(5):1009-16, 2013
5. Saadai P et al: The pathological features of surgically managed adrenal cysts: a 15-year retrospective review. Am Surg. 79(11):1159-62, 2013
6. Sebastiano C et al: Cystic lesions of the adrenal gland: our experience over the last 20 years. Hum Pathol. 44(9):1797-803, 2013
7. El-Hefnawy AS et al: Surgical management of adrenal cysts: single-institution experience. BJU Int. 104(6):847-50, 2009
8. Chien HP et al: Adrenal cystic lesions: a clinicopathological analysis of 25 cases with proposed histogenesis and review of the literature. Endocr Pathol. 19(4):274-81, 2008
9. Song JH et al: The incidental adrenal mass on CT: prevalence of adrenal disease in 1,049 consecutive adrenal masses in patients with no known malignancy. AJR Am J Roentgenol. 190(5):1163-8, 2008
10. Elsayes KM et al: Adrenal masses: MR imaging features with pathologic correlation. Radiographics. 24 Suppl 1:S73-86, 2004
11. Guo YK et al: Uncommon adrenal masses: CT and MRI features with histopathologic correlation. Eur J Radiol. 62(3):359-70, 2007
12. Sanal HT et al: Imaging features of benign adrenal cysts. Eur J Radiol. 60(3):465-9, 2006
13. Akçay MN et al: Hydatid cysts of the adrenal gland: review of nine patients. World J Surg. 28(1):97-9, 2004
14. Elsayes KM et al: Adrenal masses: MR findings with pathologic correlation. RadioGraphics 24: S73-86; 2004
15. Kawashima A et al: Imaging of nontraumatic hemorrhage of the adrenal gland. Radiographics. 19(4):949-63, 1999
16. Neri LM et al: Management of adrenal cysts. Am Surg. 65(2):151-63, 1999
17. Otal P et al: Imaging features of uncommon adrenal masses with histopathologic correlation. Radiographics. 19(3):569-81, 1999
18. Kawashima A et al: Spectrum of CT findings in nonmalignant disease of the adrenal gland. Radiographics. 18(2):393-412, 1998
19. Tung GA et al: Adrenal cysts: imaging and percutaneous aspiration. Radiology. 173(1):107-10, 1989

Images

Selected Images

Axial CECT in a 28-year-old woman with abdominal pain shows an incidental left adrenal cystic lesion . Note thin cyst septation , a finding characteristic of endothelial adrenal cyst.

Axial CECT in a 28-year-old woman with abdominal pain shows an incidental left adrenal cystic lesion . Note thin cyst septation , a finding characteristic of endothelial adrenal cyst.

Longitudinal US in the same patient confirms an anechoic left suprarenal-adrenal cyst . The simple appearance of the cyst and the lack of additional relevant clinical history (malignancy, HTN, etc.) prompted surveillance rather than resection for this incidental, benign endothelial cyst.

Longitudinal US in the same patient confirms an anechoic left suprarenal-adrenal cyst . The simple appearance of the cyst and the lack of additional relevant clinical history (malignancy, HTN, etc.) prompted surveillance rather than resection for this incidental, benign endothelial cyst.

Axial NECT in a 71-year-old woman shows a 4-cm, complex cystic right adrenal mass containing coarse calcifications. Adrenalectomy (performed given lesion complexity and size) confirmed hemorrhagic pseudocyst.

Axial NECT in a 71-year-old woman shows a 4-cm, complex cystic right adrenal mass containing coarse calcifications. Adrenalectomy (performed given lesion complexity and size) confirmed hemorrhagic pseudocyst.

Axial T2 FS MR in a 54-year-old woman with left flank pain shows a 7-cm, complex cystic right adrenal mass with a low-signal hemosiderin ring . A pseudocyst was resected. Signal intensity of pseudocysts varies depending on the age of hemorrhage.

Axial T2 FS MR in a 54-year-old woman with left flank pain shows a 7-cm, complex cystic right adrenal mass with a low-signal hemosiderin ring . A pseudocyst was resected. Signal intensity of pseudocysts varies depending on the age of hemorrhage.

Sagittal US in a 35-year-old woman shows a > 10-cm right suprarenal cyst . Real-time examination and a follow-up MR (not shown) confirmed simple extrarenal-adrenal cyst that was subsequently resected. An epithelial cyst (a rare subtype of adrenal cysts) was shown at histology.

Axial CECT in a 51-year-old woman shows an incidental, peripherally calcified left adrenal cyst . Coarse calcification suggests a pseudocyst. Pseudocysts may be due to prior trauma/hemorrhage, but this history is often absent.

Axial CECT in a hypertensive 36-year-old woman shows a peripherally enhancing, septated, 7-cm left adrenal pheochromocytoma . Enhancing soft tissue should prompt testing for an underlying adrenal neoplasm.

Axial CECT in a 72-year-old man with pancreatitis shows peripancreatic infiltration and a 3-cm adrenal pseudocyst . The pseudocyst resolved on follow-up CT. Imaging surveillance is advocated for asymptomatic, probable pseudocysts.

Staging CECT in a 66-year-old man with metastatic lung carcinoma shows large, bilateral, necrotic adrenal metastases . The clinical history and an enhancing rind prevent an erroneous diagnosis of benign adrenal cysts.

Axial CECT of a 62-year-old man shows a 2-cm, incidental left suprarenal lesion . Location adjacent to the left crus and separate from the left adrenal indicates a retroperitoneal bronchogenic cyst, a mimic of adrenal cyst.

Additional Images

Sagittal US shows a sonolucent mass above the right kidney that proved to be an adrenal cyst.

Axial T2 MR shows a high-signal left adrenal cyst .

Axial CECT shows a nonenhancing water density right adrenal cyst.

Sagittal reformation of CECT shows a nonenhancing right adrenal cyst .