BACKGROUND A variety of soft-tissue tumours result in soft-tissue masses, which are all differential diagnoses of soft-tissue sarcomas. A rare cause is extra-nodal lymphoma which, unlike a soft-tissue sarcoma which it mimics, should not be excised, but rather treated by chemotherapy and/or radiotherapy. The aim of the present study was to identify clinical, radiological, biopsy and management features of lymphoma when presenting as a soft-tissue mass. METHODS A review of 17 cases of soft-tissue lymphoma presenting as a soft-tissue mass from a total database of 295 soft-tissue tumours was undertaken. Lymphomas arising in cervical, axillary and inguinal nodes were excluded. RESULTS All patients presented with a soft-tissue mass but none had the symptoms of lymphoma. Computed tomography scanning identified seven (54%) of 13 with regional lymphadenopathy, six (46%) of 13 with encasement of major vascular structures and three with invasion across major soft-tissue boundaries. Core biopsy established a diagnosis in 13 patients (sensitivity 93%). All patients were treated with either chemotherapy and/or radiotherapy and all are alive with a mean follow up of 19 months. None underwent major resectional surgery. CONCLUSIONS The present series highlights a rare subgroup of patients with extra-nodal soft-tissue lymphoma mimicking soft-tissue sarcoma. Core biopsy is accurate in their diagnosis. Computed tomography scanning may show features suggesting the diagnosis.