Aim: To identify the clinical features of patients who present with soft tissue metastases (from a cancer elsewhere) and to identify the source of the cancer.

Method: In a database containing details of 7242 patients referred to our unit for investigation of a soft tissue lump, only 100 of these patients were found to have a soft tissue metastasis (1.4%). We analysed their presenting features and identified the site of the primary malignancy.

Results: The most common presentation of soft tissue metastases was a painless lump The lumps ranging from 2 to 35 cm (mean 8.3cm) with 78% of the lumps located deep to the fascia. The mean age at presentation was 62 and there were equal males and females. 53 had a past history of malignancy. Of these 53, 52 had metastases from the same primary (lung 11, melanoma 10, kidney 9, GI tract 4, breast 6, bladder 4 and others in 9). The other 47 patients had no past history of malignancy and the metastasis was the first presentation of malignancy. The primary sites in these cases were: lung in 19, GI tract 4, kidney 2, melanoma 9, other 3 and unknown (despite investigations) in 10. There was no correlation of the site of the metastases with the primary tumour.

Of the 7242 patients with soft tissue lumps, 476 had a past history of malignancy. Of these patients, only 12% actually had a soft tissue metastasis while 28% had a benign diagnosis, 55% a soft tissue sarcoma and 5% other malignancy.

Conclusion: Patients with a past medical history of malignancy and a new soft tissue lump have a 12% chance of it being a soft tissue metastasis. If a lump proves to be a soft tissue metasasis, the lung is the most common primary site.