Perineural Spread of Nonmelanoma Skin Cancer to the Brachial Plexus: Identifying Anatomic Pathway(s).

BACKGROUND: Perineural spread leading to brachial plexopathy has recently been described in cases of melanoma. The occurrence and mechanism for nonmelanoma skin cancer spread to the brachial plexus is poorly understood.

METHODS: A retrospective chart review of the Mayo Clinic database was conducted to identify patients with nonmelanoma skin cancer and brachial plexopathy between 2000 and 2017. Inclusion criteria were a history of nonmelanoma skin cancer, a clinical diagnosis of brachial plexopathy, imaging features of perineural spread, and a positive result of examination of a biopsy specimen showing tumor in a skin nerve.

RESULTS: Thirty-seven patients with a history of nonmelanoma skin cancer and brachial plexopathy were identified. Inclusion criteria were fulfilled in 2 cases of cutaneous squamous cell carcinoma. One case of recurrent basal cell carcinoma with perineural spread confirmed in the brachial plexus by pathologic examination was excluded because confirmatory evidence of perineural spread from the skin to the brachial plexus was not available.

CONCLUSIONS: Perineural spread of nonmelanoma skin cancer leading to brachial plexopathy is rare. Our 2 cases and the cases found in the literature demonstrate different entry points to the neural highway resulting in neurologic deficits. The cervical plexus serves as a hub for further spread in certain cases of perineural spread of skin cancer.