Soft-tissue sarcomas in the inguinal region may present as deep vein thrombosis.

Swelling, pain, and discoloration in the affected extremities are classic symptoms of deep vein thrombosis (DVT), although these symptoms are often unreliable for diagnosis, and wide differential diagnoses exist. Soft-tissue sarcomas arising in the inguinal region may encompass or be adjacent to femoral vessels and result in venous obstruction, mimicking symptoms of DVT. We present two cases of soft-tissue sarcomas in the inguinal region that were initially misdiagnosed as spontaneous DVT and administered unnecessary long-term anticoagulation therapy. In patients diagnosed with unprovoked DVT, especially young patients aged <45 years, we recommend a careful physical examination and ultrasonography in the inguinal region to prevent overlooking possible underlying malignancy, as delays in diagnosis may affect prognosis.