case_images: PMC11798580_01
case_images: Lumbar spine MRI showing enhancement of the posterior paraspinal muscles on the left side at the L4-L5 level. No osseous enhancement or abscess was present.
case_images: cureus-0017-00000077022-i01.jpg
case_images: PMC11798580_01_cureus-0017-00000077022-i01.jpg
case_images: FIG1
case_images: A lumbar spine magnetic resonance imaging (MRI) with and without contrast exhibited enhancement of the posterior left paraspinal muscles with degenerative changes and foraminal narrowing at L4-L5 (Figures 1, 2).
case_images: Lumbar spine MRI showing questionable associated epidural enhancement at the L5-S1 level, likely infectious in nature. No abscess or drainable collection was noted.
case_images: cureus-0017-00000077022-i02.jpg
case_images: PMC11798580_01_cureus-0017-00000077022-i02.jpg
case_images: FIG2
case_images: A lumbar spine magnetic resonance imaging (MRI) with and without contrast exhibited enhancement of the posterior left paraspinal muscles with degenerative changes and foraminal narrowing at L4-L5 (Figures 1, 2).
case_images: MRI of the pelvis with and without contrast showing the 5.5 x 1.2 x 5.7 cm presacral abscess formation.. Of note, there was an intradural extension at the level of the left S1 and S2 neural foramen. Phlegmonous change over the lateral aspect of the left gluteus maximus muscle belly deep to the iliotibial band with small-volume abscess formation. No evidence of acute osteomyelitis.
case_images: cureus-0017-00000077022-i03.jpg
case_images: PMC11798580_01_cureus-0017-00000077022-i03.jpg
case_images: FIG3
case_images: Subsequently, an MRI of the pelvis with and without contrast suggested findings of a left sacroiliac joint septic arthritis, with 5.5 x 1.2 x 5.7 cm presacral abscess formation (Figure 3).
case_images: Irregular edema and enhancement in the left gluteus maximus, piriformis, iliacus, posterior psoas, and left paraspinal muscles, indicative of pyomyositis.
case_images: cureus-0017-00000077022-i04.jpg
case_images: PMC11798580_01_cureus-0017-00000077022-i04.jpg
case_images: FIG4
case_images: Irregular edema and enhancement throughout the left gluteus maximus, piriformis, iliacus, posterior psoas, and left paraspinal musculature were seen - highly suggestive of pyomyositis (Figure 4).