P0208 - Sometimes There Is More to an Abscess Than Antibiotics!

Syed H. Abbas, MD¹, Saad Bin Jamil, MD², Mehrunissa Kazim, MD³, Iqra Patoli, MD^2
1Saint Marys Hospital, Waterbury, CT; ²St. Mary's Hospital, Waterbury, CT; ³Holyoke Medical Center, Holyoke, MA

Introduction: Iliopsoas abscess (IPA) can have a variable presentation and may be due to several underlying etiologies. We present a unique case of IPA due to metastatic colon cancer with an unusual presentation

Case Description/Methods: 53-year-old man with a past medical history significant for diabetes mellitus, hypertension, opioid dependence presented to the emergency room due to abdominal pain. Computed Tomography (CT) showed mass along with left IPA with apparent invasion into the distal descending colon. Initially, there was a concern for sarcoma. MRI abdomen and pelvis was done which suggested possible abscess or cancer such as sarcoma, possibly invading into the colon. Biopsy of iliopsoas mass was done, and tissue culture grew Escherichia Coli. The patient was started on antibiotics. PCR for tuberculosis was negative. Later the initial biopsy came back positive for colon adenocarcinoma. The patient was diagnosed with metastatic colon cancer. The iliopsoas mass was considered to be an extension from the adjacent sigmoid colon with secondary infection of a necrotic tumor

Discussion: IPA is not a common pathology. Primary IPA can be caused by lymphatic or hematogenous spread. However, secondary IPA is often due to local spread and can be associated with gastrointestinal etiologies such as Ulcerative colitis, instrumentation, Appendicitis, and Crohn's disease. Colon carcinoma, although extremely rare, can lead to secondary IPA (Menon, et al, 2018). The mechanism of abscess formation due to colon cancer is not established but may be due to tumor necrosis leading to abscess formation. If the tissue culture grows gram-negative rods it should further prompt physicians to consider the possible gastrointestinal cause. A Gram-negative culture must raise the suspicion of gastrointestinal or genitourinary pathology (Menon, et al, 2018). Our patient was considered to have colon cancer leading to secondary IPA. Further imaging indicated metastatic disease to the lungs and liver. Colon cancer can often be occult until late stages. Symptoms of presentation when apparent may be gastrointestinal bleeding, weight loss and decreased appetite As colon cancer is a rare cause of IPA, diagnosis of primary etiology can be delayed which may lead to long-term morbidity and mortality.

IPA can be of primary or secondary origin and can be due to multiple causes. It is important to keep in mind the various differentials and remember that colon carcinoma, although extremely rare, can lead to secondary IPA


Disclosures:


Syed H. Abbas, MD¹, Saad Bin Jamil, MD², Mehrunissa Kazim, MD³, Iqra Patoli, MD². P0208 - Sometimes There Is More to an Abscess Than Antibiotics!, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.