Iliopsoas Abscesses in Cancer

Background: Iliopsoas abscess (IPA) is a rare but potentially life-threatening condition characterized by purulent infection within the psoas compartment. Immunocompromised patients, particularly those with malignancy, are at increased risk due to factors such as neutropenia, mucosal barrier injury, and prior instrumentation. While both hematogenous and contiguous sources of infection are described, there is limited literature characterizing IPA specifically in cancer patients. Methods: We conducted a focused literature review of IPA in oncologic populations and present a case series of 3 patients with active or recently diagnosed malignancy who developed psoas abscesses. Each case was examined for clinical presentation, diagnostic findings, microbiologic profile, and management strategies. Results: The first patient, with metastatic colon cancer and a chronic enterocutaneous fistula, developed a polymicrobial left psoas abscess including Escherichia coli , Veillonella , and Streptococcus anginosus . The second patient, with therapy-related acute myeloid leukemia (AML), presented with profound neutropenia and a monomicrobial MRSA abscess. The third patient, with newly diagnosed multiple myeloma, had a small left-sided psoas abscess in the context of MRSA bacteremia, spinal discitis, and paraspinal extension. All patients underwent CT-guided drainage and received targeted antimicrobial therapy based on culture data. Discussion: This series highlights the heterogeneity of IPA in cancer patients, including varied routes of infection (fistula formation and hematogenous spread), microbial profiles (polymicrobial vs. MRSA), and radiographic findings. The diagnostic challenge is compounded by nonspecific symptoms and frequent absence of the classic psoas triad, especially in neutropenic individuals. Imaging remains central to diagnosis, and management requires individualized antimicrobial therapy and source control. As cancer survival improves and immunosuppressive therapies expand, clinicians should maintain a high index of suspicion for IPA in oncologic patients with abdominal or hip pain, even in the absence of systemic signs.