Investigating the Anatomic Location of Soft Tissue Fillers in Noninflammatory Nodule Formation: An Ultrasound-Imaging-Based Analysis

INTRODUCTION: Noninflammatory nodules may be persistent to dissolve. To evaluate the possible reasons, a case series of ultrasound images and medical data of patients who were prospectively referred with noninflammatory nodules were evaluated. MATERIALS AND METHODS: A total of 27 patients with nodules but without signs of inflammation were included. All cases were assessed with an 18-MHz linear ultrasound device. Exact location of the filler material was noted. Relations with clinical data were analyzed using chi-square tests. RESULTS: Early onset of complaints (<2 weeks) was found in 16 patients and late onset (>2 weeks) in 11. All patients had multiple nodules. In all cases, the filler nodule was found to be located inside the fascia. Extension to the subcutaneous tissue was seen in 8 cases and to the deeper planes in 5. In 14 cases, the filler material was completely located inside layers of the fascia, and migration was observed in 5 cases. DISCUSSION: Accumulation of filler material in the superficial musculoaponeurotic system or fascia may be an important cause for the occurrence of persistent noninflammatory nodules, either by initial faulty injection technique or by later accumulation through the pathway generated with a needle or cannula. Ultrasound-guided injections are helpful to dissolve the nodule.