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 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 Ga PET/CT. Moreover, SSTRs expressed in desmoid tumors could be further investigated as a therapeutic target.