What is the significance of popcorn calcification?

From the Guidelines

Popcorn calcification is a strong predictor of benign etiology in pulmonary nodules, with an odds ratio of 0.07-0.20, and therefore rarely requires further investigation or biopsy unless other suspicious features are present 1.

Key Characteristics of Popcorn Calcification

• Typically appears as large, coarse, irregular calcifications on medical imaging
• Most commonly associated with benign pulmonary nodules, such as hamartomas
• Usually larger than 2-3mm in size and have well-defined margins
• Develops in older nodules as they undergo degeneration and calcification

Clinical Implications

• Popcorn calcification is a reliable indicator of benign etiology, and therefore, further investigation or biopsy is rarely necessary unless other suspicious features are present 1
• However, any new calcifications should be evaluated by a healthcare provider through appropriate imaging such as CT or PET/CT to monitor for any changes and to detect other potential abnormalities in the lung tissue
• Regular screening CT scans are still important for individuals with popcorn calcifications to monitor for any changes and to detect other potential abnormalities in the lung tissue

Predictors of Malignancy

• Age, current or former smoking status, pack-years of smoking, previous history of extrapulmonary cancer, nodule diameter, spiculation, upper lobe location, pleural indentation, and volume doubling time <400 days are all predictors of malignancy 1
• However, the presence of popcorn calcification is a strong predictor of benign etiology, and therefore, these nodules can be safely monitored with regular CT scans unless other suspicious features are present 1

From the Research

Popcorn Calcification Characteristics

• Popcorn calcifications are areas of disorganized hyperdense lines in the metaphysis and epiphysis around the growth plate on lower limb radiographs, commonly found in children with osteogenesis imperfecta (OI) 2, 3
• These calcifications appear as a collection of scalloped radiolucencies, each with a sclerotic margin and sometimes with central densities 3
• They are often observed around the knees and ankles, and are associated with irregularity or absence of the normal horizontal growth plate 3

Incidence and Progression

• Popcorn calcifications are present in approximately 52% of children with type III OI, and 10% of children with type IV OI 2
• The mean age of onset is around 7 years, with a range of 4-14 years 2
• These calcifications are observed only during active skeletal growth, and are not present at birth 3

Molecular Correlation

• The type I collagen mutations associated with popcorn calcifications occur equally in both COL1A1 and COL1A2, and have no preferential location along the chains 2
• Popcorn calcifications do not distinguish cases with defects in collagen structure (primarily dominant type III OI) or modification (recessive type VIII OI) 2