Rare hip infection presented as a giant pseudotumor

What the study found: The authors report the first documented case of a hip periprosthetic joint infection presenting as a giant multilocular pseudotumor in a 68-year-old woman 14 years after total hip arthroplasty. The infection was caused by Granulicatella adiacens, a rare pathogen.
Why the authors say this matters: The study suggests that clinicians should be aware of atypical pathogens in periprosthetic joint infection, and the authors conclude that advanced diagnostics and interdisciplinary management are valuable. The authors also raise the hypothesis that pseudotumor environments may facilitate infection.
What the researchers tested: This is a case report of a single patient with hip periprosthetic joint infection. The diagnosis was supported by aspiration and intraoperative samples, with identification of G. adiacens by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF), a laboratory method used to identify microorganisms.
What worked and what didn't: Despite normal inflammatory markers, the infection was identified from aspiration and operative samples. Multimodal surgical treatment, including pseudotumor resection, neurolysis, staged component exchange, and targeted antibiotics, led to full recovery and infection-free follow-up.
What to keep in mind: The report describes one case only, so its findings are limited to this patient. The abstract does not provide further limitations beyond noting that this is the first documented case and that the pseudotumor-infection relationship is a hypothesis.

Key points

• This was the first documented hip periprosthetic joint infection presenting as a giant multilocular pseudotumor.
• The causative organism was Granulicatella adiacens, identified from aspiration and intraoperative samples.
• Normal inflammatory markers did not rule out infection in this case.
• Treatment included pseudotumor resection, neurolysis, staged component exchange, and targeted antibiotics.
• The patient had full recovery and infection-free follow-up.