Fibromatosis mimicking relapse of a neuroendocrine tumor at 68Ga-DOTATOC positron-emission tomography/computed tomography

Mesenteric fibromatosis (desmoid tumor) is a locally aggressive fibroblastic lesion, characterized by a high recurrence rate that makes treatment challenging. Currently, there is no evidence-based treatment approach. We report the case of a female patient with a history of neuroendocrine tumor, who underwent( 68)Ga-DOTATOC positron-emission tomography/computed tomography (PET/CT), showing increased focal abdominal uptake suggestive of disease relapse. Histological examination revealed typical findings of fibromatosis. These findings indicate the expression of staining for somatostatin receptors (SSTRs) on fibromatosis cell surface and suggest to include fibromatosis among the potential causes of false-positive results at 68Ga PET/CT. Moreover, SSTRs expressed in desmoid tumors could be further investigated as a therapeutic target.

Automated summary

Mesenteric fibromatosis is a locally aggressive fibroblastic lesion with a high recurrence rate. This study found that the tumor cells express somatostatin receptors and suggested that it could be one of the potential causes of false-positive results in 68Ga PET/CT.