Ultrasound diagnosis and Doppler monitoring of a pelvic spleen in pregnancy

We describe a patient with a pelvic spleen diagnosed during pregnancy and monitored through gestation which we believe to be the first reported case. A 40-year-old woman was referred at 8 weeks of gestation because of a chronic intense pain in the left iliac cavity which had spread to her lower back. Clinical examination revealed a poorly defined pelvic mass. Pelvic ultrasound demonstrated a gestational sac containing a viable embryo whose size was consistent with the period of amenorrhea. While the splenic area in the left hypocondrium was found to be empty, a homogeneous and elongate mass measuring 152 x 123 mm with a maximum thickness of 53.4 mm was observed in the left iliac cavity above the uterus. This mass, the ectopic spleen, was monitored by Doppler velocimetry at monthly intervals until delivery and no variation throughout gestation was observed; therefore, despite the occasional occurrence of heavy pain, it was possible to exclude circulatory complications such as thrombosis or torsion. Doppler ultrasound proved to be a useful tool for the differential diagnosis of this rare anatomical variation.