What are milk of calcium cysts?

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Last updated: April 16, 2025View editorial policy

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From the Guidelines

Milk of calcium cysts are benign and do not require specific treatment, as they are generally asymptomatic and considered a normal variant rather than a disease. These cysts commonly occur in various parts of the body and have a characteristic appearance on imaging studies due to calcium deposits. The provided evidence from the NCCN clinical practice guidelines in oncology 1 focuses on breast cysts and their classification, but it does not directly address milk of calcium cysts. However, the general principle of managing benign cysts can be applied, emphasizing the importance of monitoring and symptom management over aggressive intervention.

  • Key characteristics of milk of calcium cysts include:
    • Benign fluid collections with calcium deposits
    • Milky or creamy appearance on imaging
    • Common locations include kidneys, breasts, and gallbladder
    • Generally asymptomatic and considered a normal variant
  • Management considerations:
    • No specific treatment typically required
    • Monitoring without intervention for asymptomatic cases
    • Symptom management for rare cases with associated pain or discomfort
    • Characteristic fluid-calcium level on imaging helps distinguish from more concerning calcifications Given the benign nature of milk of calcium cysts and the lack of direct evidence suggesting otherwise, a conservative approach focusing on reassurance and occasional follow-up imaging for stability is recommended, as supported by the principle of managing similar benign conditions 1.

From the Research

Definition and Characteristics of Milk of Calcium Cysts

  • Milk of calcium (MOC) is a rare type of stone that is a viscous colloidal suspension of calcium salts 2.
  • MOC cysts can occur in various parts of the body, including the kidneys and breast.
  • In the kidneys, MOC stones are often faint radio-opaque or radiolucent and can be diagnosed preoperatively with non-contrast CT scans 2.
  • In the breast, MOC is a benign entity that presents as sedimented calcifications within small cysts, producing a "teacup"-shaped appearance on true lateral views and smudged calcifications on craniocaudal views 3, 4, 5.

Diagnosis and Management of Milk of Calcium Cysts

  • The diagnosis of MOC cysts depends on the demonstration of characteristic radiological signs, such as the "half-moon" configuration on horizontal beam radiography or the "teacup" sign on mammography 3, 6.
  • In the kidneys, MOC stones can be managed effectively with percutaneous nephrolithotomy (PCNL) with suction and retrieval of soft stones without the need for disintegration 2.
  • In the breast, the recognition of MOC is important to avoid unnecessary workup, follow-up, or biopsy, as it is a benign entity 3, 4, 5.

Radiological Signs and Differentiation from Malignant Lesions

  • The radiological signs of MOC cysts are characteristic and can be distinguished from malignant lesions, such as renal stones or breast carcinomas 2, 3, 4, 5, 6.
  • In the kidneys, MOC stones can be differentiated from renal stones by their location in a dependent position, fluid level, or semilunar pattern on non-contrast CT scans 2.
  • In the breast, MOC can be differentiated from malignant microcalcifications by their characteristic "teacup"-shaped appearance on true lateral views and smudged calcifications on craniocaudal views 3, 4, 5.

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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