Background: Desmoid tumors are uncommon fibromatous tumors arising from musculoaponeurotic tissue characterized by spindle cell fibroblast and myofibroblast proliferation. The cause is unknown (trauma, hormonal factors, genetic anomaly...). Locally invasive, they tend to recur increasing morbidity or even mortality.
Case report: Stiff shoulder resulting from blockage of the scapulothoracic articulation was the inaugural sign. Three-phase bone scintigraphy demonstrated early uptake in the soft tissue in contact with the scapula. Magnetic resonance imaging and biopsy confirmed the diagnosis of desmoid tumor. Complete resection was performed. No adjuvant radiotherapy nor hormone treatment were given since no antiestrogen receptor antibodies were identified on the surgical specimen.
Discussion: The clinical manifestation (stiff shoulder) and the scapular localization observed in this case are unusual for desmoid tumors. Initially tendinopathy of the shoulder, acromio-clavicular arthropathy and capsular retraction of the shoulder joint had been entertained. Early diagnosis and wide surgical resection are indicated in desmoid tumors.