Rationale: Primary iliopsoas abscess (IPA), an uncommon clinical entity, often has no specific clinical features, and advanced imaging techniques are often required for diagnosis.
Patient concerns: We successfully treated 3 patients with primary IPA complicated by rapid development of septic shock within 2 months.
Diagnosis: All patients were in shock at the time of admission and were diagnosed with primary IPA by history, clinical examination and imaging findings.
Interventions: All patients were treated by surgical drainage and sensitive antibiotics based on culture results.
Outcomes: The patients eventually recovered and were discharged within 2 months.
Lessons: An IPA may not be diagnosed in a timely manner because it has no specific symptoms or signs. Therefore, special attention must be given to patients with sudden onset of abdominal pain, hip pain, or high fever without an obvious cause, a primary IPA should be highly suspected in such patients.