What is the etiology of multiple peripherally calcified peritoneal nodules?

Etiology of Multiple Peripherally Calcified Peritoneal Nodules

Multiple peripherally calcified peritoneal nodules are most commonly caused by peritoneal metastases from ovarian carcinoma, particularly serous cystadenocarcinoma, followed by benign causes such as peritoneal dialysis and prior peritonitis. 1

Malignant Causes

Ovarian Carcinoma

• Serous cystadenocarcinoma of the ovary is the most common malignancy associated with calcified peritoneal nodules, with histologic calcification present in approximately 30% of cases 2
• Peritoneal metastases from ovarian cancer typically present as multiple nodular calcifications rather than sheet-like calcifications 1
• Associated calcified lymph nodes are strongly suggestive of malignancy, seen in over half of malignant cases but not in benign conditions 1
• CT imaging often reveals perihepatic calcifications in patients with metastatic ovarian carcinoma 2

Other Malignancies

• Mucinous adenocarcinoma of the colon can also metastasize to the peritoneum and present with calcified peritoneal nodules 3
• Malignant peritoneal calcifications tend to have associated soft tissue components and are more likely to have a nodular morphology 1

Benign Causes

Peritoneal Dialysis

• Long-term peritoneal dialysis is a common cause of benign peritoneal calcification 1
• Calcifications are typically sheet-like rather than nodular in appearance 1
• The mechanism is related to altered calcium-phosphate metabolism in patients with end-stage renal disease 4
• These patients may develop calcified amorphous tumors in various locations, including the peritoneum 4

Prior Peritonitis

• Previous episodes of peritonitis can lead to peritoneal calcifications 1
• The calcifications typically appear sheet-like rather than nodular 1
• These represent a sequela of the inflammatory process with subsequent dystrophic calcification 1

Tumoral Calcinosis

• A rare benign condition characterized by massive calcium deposits, often seen in patients with renal failure 5
• Can present as calcified, fluid-filled masses in various locations including the peritoneum 5
• Often associated with abnormal calcium and phosphate metabolism 5

Distinguishing Features on Imaging

CT Characteristics Suggesting Benign Etiology

• Sheet-like calcification pattern (seen in 7 of 8 benign cases in one study) 1
• Absence of associated lymph node calcification 1
• Absence of soft tissue components 1

CT Characteristics Suggesting Malignancy

• Nodular calcification pattern (more common in malignant cases) 1
• Presence of calcified lymph nodes (seen in 5 of 9 malignant cases) 1
• Associated soft tissue components 1
• Perihepatic location of calcifications 2

Clinical Approach to Evaluation

• Review prior imaging to assess for stability of nodules, as stability for at least 2 years suggests benign etiology 6
• Evaluate for history of peritoneal dialysis, prior peritonitis, or known primary malignancies 1
• Consider biopsy of dominant nodules if malignancy is suspected, especially with nodular morphology or associated lymphadenopathy 6
• In patients with known or suspected ovarian cancer, these findings should raise concern for peritoneal carcinomatosis 2

Management Considerations

• For asymptomatic calcified nodules with benign characteristics (sheet-like, stable, history of dialysis or peritonitis), observation is appropriate 6
• For nodules with suspicious features (nodular, associated lymphadenopathy, soft tissue components), further evaluation for malignancy is warranted 1
• In patients with known malignancy, these findings may indicate disease progression requiring treatment modification 2