Calcified desmoplastic fibroblastoma of the foot: imaging findings

We report a case of desmoplastic fibroblastoma (DF) of the foot in a 65-year-old woman. The tumor presented as a slow-growing, painless mass located in the first intermetatarsal space of the right foot. Ultrasound showed a well-circumscribed hypoechoic lesion containing hyperechoic calcifications confirmed on standard radiographs. At magnetic resonance imaging (MRI), the mass appeared isointense to the muscles on T1-weighted (T1W) images, hyperintense on proton-density-weighted fat-saturated images, and presented scattered internal hypointense foci. Post-contrast T1W spectral presaturation with inversion recovery (SPIR) images showed heterogeneous, mostly peripheral, contrast enhancement. DF must be considered in the differential diagnosis of soft-tissue calcified tumors of the foot.