Incidental finding of an undifferentiated sarcoma during lower limb Doppler ultrasound: A case report.

Introduction: Undifferentiated sarcoma is considered a rare and aggressive type of soft tissue sarcoma with the lower extremity reported as the common site for soft tissue sarcomas.

Case presentation: We present a rare incidental finding of undifferentiated sarcoma during lower limb Doppler ultrasound with a presenting symptom of right thrombotic-like calf pain in a 49-year-old female.

Discussion: On ultrasound, the presented undifferentiated sarcoma appeared as a large heterogeneous, oval-shaped, soft tissue mass deeply seated in the right calf with involvement of the soleus muscle. The features on ultrasound mimicked those of a hematoma; however, the possibility of the lesion being a haematoma was promptly ruled out with the demonstration of internal vascularity on colour Doppler application. The case was then referred to a sarcoma triage multidisciplinary team for a review. Magnetic resonance imaging, computed tomography and biopsy were parts of the diagnostic workup for this case, histology confirmed the soft tissue lesion to be an undifferentiated sarcoma. Emergency above knee amputation of the right leg was performed as part of the patient's treatment.

Conclusion: This case report presents a rare incidental finding of undifferentiated sarcoma encountered during lower limb Doppler ultrasound causing thrombotic-like calf pain. Sonographers are encouraged to pay necessary attention and carefully examine any adjacent and incidental soft tissue lesion during lower limb Doppler ultrasound using compression, two-dimensional imaging and colour imaging, especially those that appear with characteristic features of malignancy; urgent referral should be made of such cases to a tertiary soft tissue sarcoma centre for further evaluation and management.