Background
Lower back pain affects up to 70% of pregnant women, often attributed to physiological changes like weight gain, hormonal shifts, and altered posture. While most cases are musculoskeletal, this report highlights the importance of maintaining a broad differential when pain is progressive or atypical in presentation.
Case Presentation
A 30-year-old G6P5 Indigenous Australian woman had progressive lower back pain from K20 gestation, accompanied with evolving neurological symptoms including right leg numbness, weakness, and urinary hesitancy. She had a mechanical fall six months before pregnancy but no significant known spinal pathology. Serial lumbosacral MRIs showed a stable L4/5 disc bulge with mild left foraminal stenosis. Her pain was managed conservatively as presumed musculoskeletal. She delivered vaginally at term without complications. Her symptoms continued to worsen postpartum. An MR neurogram performed due to an abnormal nerve conduction study revealed a large right pelvic mass arising from the L5 nerve root. Biopsy confirmed Ewing’s sarcoma.
Discussion
This case illustrates how common complaints in pregnancy can mask rare but serious conditions. Diagnostic delay was influenced by anchoring bias toward musculoskeletal causes, pre-existing chronic back pain, and MRI findings, despite not correlating with her evolving neurological deficits. Earlier consideration of other differentials and imaging could have expedited diagnosis, even during pregnancy.
Conclusion
Clinicians should remain vigilant for atypical presentations or progressive symptoms in pregnancy that deviate from the expected course of common pathologies. This case emphasizes the importance of challenging diagnostic assumptions and broadening differentials in persistent or worsening lower back pain during pregnancy.