A retroperitoneal malignant fibrous histiocytoma is an uncommon tumour overall but is considered as one of the most common types of primary retroperitoneal neoplasms. Only 15% of all malignant fibrous histiocytomas occur within the retroperitoneum.
They are categorised as sarcomas and are often high grade tumours. They occur with predominance in men.
There are six histological subtypes: storiform, pleomorphic, myxoid, giant cell, inflammatory and angiomatoid. Most metastasize and common sites include lung and lymph nodes.
Imaging is not characteristic and clarification pathologically is required. Reassessment of malignant fibrous histiocytoma diagnosis in some series result in re-classification as dedifferentiated liposarcomas.
25% of cases include dystrophic calcification which is uncommon amongst the remaining primary retroperitoneal malignancies.
- 1. Nishino Mizuki, Katsumi Hayakawa, Manabu Minami et al. “Primary Retroperitoneal Neoplasms: CT and MR Imaging Findings with Anatomic and Pathologic Diagnostic Clues.” Radiographics 23, no. 1 (January 1, 2003): 45-57. doi:10.1148/rg.231025037.
- 2. Coindre Jean-Michel, Odette Mariani, Frederic Chibon et al. “Most Malignant Fibrous Histiocytomas Developed in the Retroperitoneum Are Dedifferentiated Liposarcomas: A Review of 25 Cases Initially Diagnosed as Malignant Fibrous Histiocytoma.” Mod Pathol 16, no. 3 (0): 256-262. [Link].