Objectives We present a case of metastatic Epithelioid haemangioendothelioma (EHE) with likely left upper limb neurovascular bundle primary that mimicked a peripheral nerve tumour. EHE are an intermediate grade tumour of the soft tissues arising from vascular endothelium. EHE have occasionally been described to involve neurovascular structures though have not been previously reported to precede metastatic disease.

Case A 70-year-old female presented with a soft, painful, non-pulsatile, progressively enlarging mass located at the proximal third and medial aspect of the left arm. This was associated with 6 months of finger weakness and intermittent numbness of the little finger and ulnar half of the ring finger. The mass was first noted and investigated 20 years prior with open biopsy revealing dense fibrous tissue involving the ulnar and median nerves, brachial artery and basilic vein. Histological analysis revealed dense fibrous and chronic inflammatory tissue with prior evidence of haemorrhage encasing the neurovascular bundle. Examination revealed weakness of finger abduction and adduction plus finger flexion of ring and little fingers. Sensation was reduced in the little finger and ulnar half of the ring finger. EMG/NCS revealed absent ulnar SNAPs and denervation changes in ulnar-innervated muscles. MRI showed a mass lesion encasing the neurovascular bundle. Over 12 months wasting and weakness of ulnar and median nerve innervated muscles progressed. Repeat NCS/EMG revealed complete ulnar neuropathy and denervation of median nerve innervated muscles. Concomitant investigations for abdominal discomfort identified multiple hepatic lesions that on biopsy were consistent with EHE. Left neurovascular bundle biopsy identified similar histological findings.

Conclusions This case highlights a rare presentation of metastatic EHE with neurovascular primary. EHE can mimic nerve sheath tumours clinically and radiologically, and should be considered in the differential diagnosis of tumours involving or adjacent to a neurovascular bundle.