MRI features of calcifying aponeurotic fibroma in the upper arm: a case report and review of the literature.

Calcifying aponeurotic fibroma is a rare soft tissue tumor that occurs in the distal extremities of children and adolescents. We report a case of pathologically proven calcifying aponeurotic fibroma in the left upper arm of a 23-year-old female. Radiographs revealed increased soft tissue density with multiple stippled calcifications in the mid-portion of the patient's left upper arm. Magnetic resonance imaging (MRI) showed a well-defined soft tissue mass with low to intermediate signal intensity on T1-weighted images, heterogeneously low signal intensity on T2-weighted images, and heterogeneous enhancement on fat-suppressed, contrast-enhanced T1-weighted images. Histologically, spindle cell proliferation with scattered calcifications and hyalinization was present. Seven years after surgery, there was no evidence of local recurrence. This is the first report of MRI findings of calcifying aponeurotic fibroma in the upper arm. We also summarize the MRI findings of 16 previously reported cases of calcifying aponeurotic fibroma originating in the upper or lower extremities.