Idiopathic Iliopsoas Muscle Hematoma

Shinya Otsubo1, and Junki Mizumoto2
1Center for Medical Training, Ehime Seikyo Hospital, Ehime, Japan
2Department of Medical Education Studies, International Research Center for Medical Education, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan

Corresponding author: Junki Mizumoto,

DOI: 10.31662/jmaj.2023-0178

Received: November 8, 2023
Accepted: December 18, 2023
Advance Publication: February 9, 2024

Key words: Emergency Medicine, Hematoma, Iliopsoas muscle

A 77-year-old man complained of severe right lateral back pain. It had developed acutely nine days earlier when the patient was riding bicycle on a steep incline; the pain relieved seven days earlier. After cycling again on the day before presentation, the pain recurred. On the day of the presentation, the pain suddenly worsened.

He had to lay down on the bed and could not move his lower limbs; he remained afebrile. Computed tomography revealed distended right iliopsoas muscle (Figure 1). There was no contrast enhancement within the lump or along its periphery, reducing the likelihood of an iliopsoas abscess. Considering the homogeneously contrasted lump and abrupt onset of pain, idiopathic iliopsoas hematoma was ascertained to be the most likely diagnosis. Laboratory tests revealed no coagulopathies. Shrinkage of the iliopsoas lump was confirmed on the fourth day after the admission (Figure 2), concomitant with pain relief, leading to a definitive diagnosis.

Figure 1. Swollen right iliopsoas muscle (white arrowheads) on contrast CT scan. (A) Horizontal view. (B) Coronal view.
Figure 2. Shrunk hematoma (white arrowheads) on non-contrast CT on fourth day. (A) Horizontal view. (B) Coronal view.

This case highlights that iliopsoas hematomas can develop in patients without predisposing factors (1), and even moderate mechanical stress can trigger their development (2). Furthermore, the pain progressing in a stepwise manner suggests a potential link between repetitive strain and hematoma development.

Article Information

Conflicts of Interest


Author Contributions

Concept: S.O., J.M.; design: S.O., J.M.; data collection or processing: S.O., J.M.; analysis or interpretation: S.O., J.M.; literature review: S.O., J.M.; and writing: S.O., J.M.

Informed Consent

Informed consent was obtained from the patient.


Shinya Otsubo: 0009-0007-0689-653X

Junki Mizumoto: 0000-0002-0783-7351


  1. 1.

    Marquardt G, Barduzal Angles S, Leheta F, et al. Spontaneous haematoma of the iliac psoas muscle: a case report and review of the literature. Arch Orthop Trauma Surg. 2002;122(2):109-11.

  2. 2.

    Kawarat V, Javid M, Swaminathan SP, et al. A rare case of iliopsoas hematoma in a patient with von Willebrand disease. Int Surg J. 2020;7(3):873-5.