Intra-abdominal desmoid tumor - very large

Case contributed by Dr Michael P Hartung


Abdominal discomfort.

Patient Data

Age: 40
Gender: Female


Large enhancing oval mass centered in mid/left abdominal mesentery, displacing bowel. Posterior tumoral vascularity. 

No metastases. 


Final diagnosis:

Soft tissue mass: desmoid-type fibromatosis.

An immostain for beta catenin shows strong nuclear staining.

Histologic sections of the abdominal mass demonstrate a proliferation of bland spindled to stellate shaped cells arranged in a long weeping fascicles. The spindle cells fail to show significant cytologic atypia. Overall, the morphologic features in conjunction with the presence of beta catenin immunopositivity are consists with desmoid-type fibromatosis.

Case Discussion

Differential diagnosis for this mass: desmoid, sarcoma, GIST, fibrous tumor, lymphoma. 

Unlikely to be aggressive or highly malignant given rounded, well-defined shape and no metastases. 

Ultrasound-guided biopsy was performed with final pathology desmoid. This was likely sporadic or related to prior childbirth.

Companion infiltrative desmoid.

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Case information

rID: 63886
Published: 23rd Oct 2018
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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