A case report and review of soft tissue metastatic squamous cell carcinoma of the upper limb in the absence of a primary tumour.

Soft tissue metastases and distant perineural metastases of an unknown primary are rare presentations of cancer. We present a patient with soft tissue and intraneural metastatic squamous cell carcinoma to the left arm with unknown primary that was treated with wide excision, followed by adjuvant radiotherapy. The patient was followed up for 3 years, and has had no signs of recurrence. We discuss the management of this patient and review available literature to share our experience of managing this rare condition. Soft tissue and perineural metastases are rare, but should form part of the differential diagnosis in patients presenting with soft tissue (or nerve) swellings. To our knowledge, the presence of metastatic soft tissue SCC in the extremity with intraneural spread in the absence of a primary tumour has not been reported in the literature.