Retroperitoneal Mass with Calcification

Differential considerations for a retroperitoneal mass with calcification can be divided into benign and malignant conditions. Benign causes can be further divided into neoplastic and non-neoplastic.

Non-neoplastic

• Posttraumatic calcified hematoma:
• Myositis ossificans: In the setting of trauma
• Foreign body granuloma: In the setting of penetrating trauma (iatrogenic or otherwise). May have contrast enhancement if there is a significant inflammatory component.

Benign neoplastic

• Tumors of neural origin: Ganglioneuroma, schwannoma, paraganglioma. Usually heterogeneous with T2-hyperintense areas and marked contrast enhancement.
• Hemangioma: Phleboliths. T2-hyperintense.
• Mature teratoma: Heterogeneous contents with with fluid and fat.

Malignant neoplastic

• Undifferentiated pleomorphic sarcoma: Formerly known as malignant fibrous histiocytoma (MFH). Heterogeneous mass with myxoid stroma and/or collagen fibers
• Dedifferentiated liposarcoma: Heterogeneous mass with or without bulky calcification in part of the tumor.
• Malignant mesenchymoma: Heterogeneous mass. By definition has two or more malignant fibrosarcomatous components.
• Malignant teratoma: Heterogeneous mass. Occurs in young patients.
• Extraskeletal osteosarcoma: Variable amount of mineralization with typically intense and amorphous calcification. Nonmineralized areas iso-attenuating to muscle and intermediate signal on T1-weighted images. Variable contrast enhancement.

References

Secil M, Mungan U, Yorukoglu K, Dicle O. Case 89: Retroperitoneal extraskeletal osteosarcoma. Radiology. 2005 Dec;237(3):880-3.