[Foot and ankle tumours : Part I: overview of incidence, diagnosis and staging of pedal tumours].

CLINICAL ISSUE: Foot and ankle tumours are rare. Part I of this paper provides a survey about tumour distribution regarding age and location of benign and malignant bone and soft tissue tumours.

STANDARD RADIOLOGICAL METHODS: All diagnostic radiological procedures are used for the diagnostic work-up of pedal tumours, in particular plain radiography, MRI, and ultrasonography.

METHODICAL INNOVATIONS: Dual-energy CT proves to be a valuable (differential) diagnostic tool in identifying urate dihydrate crystals.

PERFORMANCE: There are no reliable numbers available on accuracy of the aforementioned diagnostic procedures regarding tumour detection and identification. This is particularly true for soft tissue tumours which are small and well-defined, thus requiring histological clarification.

ACHIEVEMENTS: To evaluate pedal tumours correctly and reasonably, a full range of radiological diagnostics should be employed. Neither plain radiography alone nor a stand-alone MRI examination-depending on the tumour site-are sufficient to characterize such tumours including staging.

PRACTICAL RECOMMENDATIONS: Plain radiography remains the first-choice imaging modality. Ultrasonography is superior to reliably detect and identify ganglion cysts. MRI, however, continues to remain the upmost diagnostic modality of choice for evaluating foot and ankle tumours. CT possesses unchallanged diagnostic power to assess osseous changes. Bone scintigraphy (including SPECT-CT) and FDG-PET imaging are used when multifocal distribution or metastatic disease are suspected or to detect avidity of the pedal lesions, respectively.