chronic musculoskeletal pain ； interventional radiology ； trans-arterial embolization

Plantar fi bromatosis is a benign condition characterized by focal nodular enlargement of the plantar aponeurosis owing to local proliferation of fi brous tissues. The clinical fi ndings are a fi rm non-tender or slightly tender fi brous nodule localized at the medial aspect of the middle third of the sole (Figure 1A). Passive dorsiflexion of the toes, which tightens the aponeurosis, can result in local pain. In large-sized lesions, pain may derive from direct compression exerted by the plantar nodule against the medial plantar nerve [1]. Sonography is a useful modality of confirming the presence of plantar fi bromatosis [2]. Sonography of the plantar fi bromatosis was performed along the longitudinal and transverse view of the sole of the foot using 5–12 MHz linear array transducer with the patient lying prone and the foot resting over the edge of the examination couch (Figure 1A). The typical sonographic appearances of plantar fi bromatosis may include :

1. A fusiform nodular thickening of the plantar fascia is oriented according to its major axis as a uniform hypoechoic lesion without internal cystic or calcium deposits. The lesion is mostly located at the middle third of the plantar fascia and in continuity with the plantar fascia (Figure 1B).

2. Some nodules have moderate posterior acoustic enhancement (Figure 1B).

3. In small nodules, the deep portion of the fascia still demonstrates a normal hyperechoic fi brillar structure. The second small nodules could be found at the same or contralateral foot [2].

4. Power Doppler signals could be positive or negative, but mostly (90%) are negative [2].

Statistically, there is no correlation among the ultrasound appearance of the nodules, the duration of symptoms, and the clinical outcome [2]. The pathologies that should be differentiated from plantar fibromatosis include plantar fasciitis and chronic partial tear of the plantar fascia. Sonographically, there is a thickened, hypoechoic segment of plantar fascia mostly at the middle third of the central or medial plantar aponeurosis. Sometimes there are coincident calcaneal spurs or plantar fasciitis with plantar fibromatosis. Distinguishing between plantar fibromatosis and chronic partial tears of the plantar fascia could be challenging and may rely on a history of previous trauma and corticosteroid injection. Rupture of the plantar fascia (Figure 2), however, appears to be more easily differentiated from plantar fibromatosis based on its sonographic findings.

The authors declare no conflict of interest

Figure 1. A 55-Year-Old Man With the Left Plantar Fibromatosis

(A) Photograph of the left foot shows a discrete nodule (arrow) at the medial aspect of the middle third of the sole. (B) Longitudinal 12–5 MHz ultrasound image over the middle third of left plantar fascia demonstrates a well-defi ned fusiform hypoechoic nodule (*)
arising within the plantar fascia aponeurosis (PF) involving both deep and superfi cial plantar fascia aponeurosis.
Abbreviation: FDB, fl exor digitorum brevis.

Figure 2. Right Plantar Fascia Rupture
Longitudinal 12–5 MHz ultrasound image obtained over the central band of the plantar fascia shows marked hypoechoic swelling (green arrows) of the plantar fascia owing to acute fascial tear with intense soft-tissue edema and hemorrhage surrounding the fascia.
Abbreviations: CALC, calcaneus; LAX, long-axis.