由隐匿性周围神经基底细胞癌引起的持续超过10年的多发性脑神经病变

Background:
Between 0.2% and 2% of basal cell carcinomas are complicated by microscopic perineural invasion. The clinical features of perineural spread of basal cell carcinomas are similar to those of squamous cell carcinomas, except with respect to speed of progression. Often the failure to explicitly inquire about a history of skin cancer can lead to a missed diagnosis.

Case Report:
Man, 69, had diplopia and left ptosis of 3months' duration as well as progressive loss of left trigeminal and facial nerve function over the previous 7years. The nerve function was initially lost from the upper trigeminal branches and finally culminated in complete hemifacial anesthesia and paralysis. Repeated neurologic assessments and three magnetic resonance imaging (MRI) scans were unable to detect a cause for the problem. Although the patient denied any previous health issues, targeted questioning about skin cancer led to an examination of pathologic records, which revealed the excision of a basal cell carcinoma from the patient’s forehead 4 years before he experienced neurologic symptoms. Enhanced MRI revealed the left ophthalmic, maxillary, mandibular, and facial nerves were thickened and enhanced. Mandibular nerve biopsy yielded malignant cells infiltrating the endoneurium and perineurium, with an immunohistochemical profile similar to that of the biopsies of resected basal cell carcinoma taken 10years previously. The patient underwent radiotherapy of the left oculomotor, trigeminal, and facial nerves. A year later he returned for treatment of the right trigeminal nerve, which was now involved. He died 10years after first experiencing neurologic symptoms.

Conclusions:
The diagnosis of perineural spread from basal cell carcinoma should be considered in patients who have partial trigeminal nerve dysfunction, particularly if they have experienced progression or also have localized dysfunction of the facial nerve. Often the MRI findings are normal in these patients, but thin-slice scans with gadolinium may reveal subtle intracranial or extracranial nerve involvement. Biopsy of peripheral branches may indicate the diagnosis, avoiding craniotomy. Diagnosis and treatment before MRI abnormalities appear are associated with greatly increased survival rates.