Injectable soft-tissue fillers have been widely used for cosmetic breast augmentation; however, permanent and long-lasting fillers carry a substantial risk of delayed adverse events. Aquafilling is a polyamide hydrogel filler composed of 2% polyamide and 98% water and was previously marketed as a safe, durable option for breast augmentation. Subsequent clinical evidence has documented severe complications, including chronic inflammation, distant migration, and delayed infection, raising substantial safety concerns regarding its use [1,2]. Delayed infectious complications related to permanent breast fillers are difficult to manage because they may occur after prolonged latency, spread across extensive anatomic regions, and respond poorly to conservative treatment. We present a rare case of severe late-onset infection approximately 10 years after Aquafilling injection, with multicompartment thoracoabdominal and pelvic soft-tissue abscesses, sepsis with marked hypotension, and a need for staged surgical management.

A 51-year-old woman with no significant medical history presented to the emergency department with generalized weakness, fever, diffuse body edema, and progressive pain involving the chest wall and trunk for 7 days. She also reported purulent discharge from a puncture wound at the left inframammary fold (Fig. 1). In 2015, she had undergone bilateral breast augmentation with Aquafilling (2% polyamide and 98% water). The exact injected volume in each breast could not be confirmed because the patient did not remember the amount and the procedure had been performed at an outside clinic approximately 10 years earlier. During the subsequent years, she noticed gradual caudal migration of the filler material, which produced multiple palpable masses throughout the trunk. Because these lesions remained asymptomatic, she did not seek medical treatment. Seven days before admission, she developed systemic symptoms, including fever up to 39 °C, generalized edema, and worsening pain. She had not received antibiotic therapy before admission. At presentation, she was febrile, septic, and hypotensive, with a body temperature of 39 °C, systolic blood pressure in the 70 mmHg range, and leukocytosis.

Contrast-enhanced chest computed tomography demonstrated extensive soft-tissue involvement of the anterior, lateral, and posterior chest wall, right axilla, and right shoulder. A prominent thick-walled fluid collection containing internal air densities was identified in the right anterior chest wall and extended to the inner and outer aspects of the ribs at the level of the cardiac base. A skin defect was also observed in the left lateral chest wall, suggesting cutaneous involvement by the infected migrated filler collection (Fig. 2). Abdominopelvic computed tomography revealed multiple variable-sized cystic fluid collections within the abdominal wall, the largest measuring up to 27.5 cm in maximal diameter. Several lesions had thickened walls and perilesional fat infiltration, raising suspicion for complicated filler-related fluid collections or abscesses (Fig. 3).

Initial laboratory evaluation showed leukocytosis (12.0×10³/μL), thrombocytosis (529×10³/μL), markedly elevated inflammatory markers (erythrocyte sedimentation rate, 120 mm/hr; C-reactive protein, 23.23 mg/dL), and hypoalbuminemia (3.2 g/dL). Renal and hepatic function test results were within normal limits.

Because the patient presented with sepsis and hypotension, emergent incision and drainage were performed on the day of admission. Blood cultures and intraoperative pus specimens were obtained before empirical intravenous piperacillin-tazobactam was started. Extensive purulent material was found in both breasts and in the lower abdominal and pelvic soft-tissue regions, and four Hemovac drains were placed. The total volume of evacuated purulent material was estimated to exceed 1,000 mL (Fig. 4). Intraoperative pus specimens were submitted for aerobic, anaerobic, fungal, and acid-fast bacilli cultures, and two sets of blood cultures were obtained before antibiotic administration. All pus cultures, including aerobic, anaerobic, fungal, and acid-fast bacilli cultures, showed no growth, and both sets of blood cultures were negative. Empirical intravenous piperacillin-tazobactam was continued for 2 weeks, and no additional oral antibiotics were prescribed after discharge. On postoperative day 3 (POD 3), follow-up breast magnetic resonance imaging showed multiple variable-sized rim-enhancing lesions involving both breasts, the chest wall, and axillae, with diffuse soft-tissue edema and internal air signals, consistent with persistent filler-related abscesses. On POD 7, a second staged operation was performed because persistent abscess cavities remained. The cavities were thoroughly curetted and irrigated, and additional drains were placed in the right axilla, chest wall, and left abdominal wall. Drains were removed sequentially after output remained below 10 mL/day for two consecutive days, and all drains had been removed by POD 15. A follow-up contrast-enhanced computed tomography scan obtained before discharge confirmed near-complete resolution of all previously identified abscesses and inflammatory changes, with no residual drainable fluid collection or newly developed infectious focus (Fig. 5). Inflammatory markers had normalized by the day of discharge. On POD 15, the white blood cell count was 4.8×10³/μL and the C-reactive protein level was 0.2 mg/dL. At 9 months postoperatively, she remained well, with no recurrent infection, skin necrosis, or significant breast deformity, and her scars were minimally conspicuous.

Because Aquafilling and other copolyamide-based fillers were used for breast augmentation in some Asian countries during the previous decade, plastic surgeons may encounter delayed complications after long latency periods. This case shows that migrated polyamide hydrogel filler can present not only as localized breast inflammation but also as life-threatening multicompartment soft-tissue infection many years after injection. The approximately 10-year latency, thoracoabdominal and pelvic involvement, culture-negative findings, and objective radiologic confirmation of near-complete resolution distinguish this case from typical early filler-related infections.

Delayed infections associated with permanent fillers are thought to arise from chronic foreign-body reactions and biofilm formation on implanted materials [3-5]. Although all intraoperative pus and blood cultures were negative, these findings should not be interpreted as evidence that infection was absent. Biofilm-associated microorganisms may persist in a quiescent state and evade detection by conventional culture techniques. Extensive sterile liquefaction related to chronic foreign-body inflammation around the migrated polyamide hydrogel material may also have contributed to the large volume of culture-negative purulent or turbid filler-related fluid.

A defining feature of this case was the extensive caudal migration of Aquafilling, which led to multicompartment involvement of the chest wall, abdominal wall, and pelvic soft-tissue regions. Polyamide hydrogel fillers do not truly integrate with tissue and may migrate along loose areolar tissue and fascial planes under the influence of gravity [1,2]. Over time, this migration can create large, poorly vascularized spaces that are highly susceptible to infection. Although computed tomography and magnetic resonance imaging were essential for evaluation and operative planning, the intraoperative findings showed more extensive soft-tissue involvement than imaging suggested, highlighting the need to interpret imaging findings together with clinical and operative findings in complex soft-tissue infections [6].

From a surgical standpoint, simple incision and drainage are insufficient for extensive filler-related abscesses. Because the filler material can serve as a persistent nidus for infection, definitive management requires aggressive surgical source control, including evacuation of abscess cavities, reduction of the infected filler burden as much as feasible, copious irrigation, and staged surgical intervention when necessary [7,8].

Several reports in Archives of Aesthetic Plastic Surgery have described delayed complications and migration after Aquafilling or copolyamide breast filler injection. Kim et al. [9] reported delayed purulent breast infection after large-volume Aquafilling injection, and Yoon et al. [10] described distant migration of copolyamide breast filler to the lower abdominal wall and inguinal region. More recently, Choi et al. [11] reported severe systemic dissemination of copolyamide breast filler with multifocal abscess formation, including mediastinal involvement. Compared with these reports, the present case is notable for extensive thoracoabdominal and pelvic soft-tissue abscess formation approximately 10 years after injection, septic presentation with marked hypotension, a culture-negative purulent collection exceeding 1,000 mL, staged surgical drainage, and near-complete radiologic resolution before discharge.

This condition warrants particular attention in plastic surgery practice because permanent or long-lasting breast fillers can cause severe infectious complications after prolonged latency. This case emphasizes the need for long-term vigilance, careful history taking, early recognition, and aggressive surgical source control in delayed filler-related infections after breast augmentation with polyamide hydrogel fillers.

This case has several limitations. The exact injected volume of Aquafilling in each breast could not be confirmed because the patient did not remember the amount and no outside procedural records were available. Therefore, the relationship between injection volume and the extent of migration or abscess formation could not be assessed.