A Case of Shoulder Desmoid-Type Fibromatosis Missed on an Initial Work Up: Case Report and Literature Review

Abstract

Desmoid-type fibromatosis (DF) is a rare, locally invasive, non-metastasizing soft tissue proliferation derived from mesenchymal progenitor cells. The incidence of DF is 2 to 4 per million per year in the general population and typically affects adults between the ages of 35 - 40. Desmoid-type fibromatosis can either be sporadic or associated with mutation in the adenomatous polyposis coli gene. Trauma, surgery, pregnancy, and oral contraceptives have been identified as risk factors for the development of desmoid-type fibromatosis. MRI is the standard for image characterization, and CT image-guided core needle biopsy for diagnosis. “Wait and see” is the current management recommendation, and studies of y-secretase inhibitors and tyrosine kinase inhibitors have shown promise in the treatment of desmoid-type fibromatosis. This report presents a case of rare right shoulder desmoid type fibromatosis in a 48-year-old male that was missed on an initial workup including EMG/NCS and shoulder MRI, and demonstrates the importance of revisiting the diagnostic process if a former workup has yielded an unclear clinical picture.