Breast cancer recurrence presenting with numb chin syndrome

What happened, in summary

A 51-year-old woman had been diagnosed with Stage II left breast cancer in 2006. She underwent a left mastectomy with reconstruction followed by adjuvant radiotherapy. In 2015, a sternal metastasis was identified and treated with radiotherapy and letrozole.

She later developed 2 weeks of progressive, intermittent numbness over the left chin together with bilateral lower-limb pain and anterior chest-wall pain. Examination showed reduced sensation over the left mandibular region without swelling, trismus, toothache or other obvious dental cause.

PET/CT demonstrated hypermetabolic disease at the left mandibular foramen and sternum, while skull CT showed cortical invasion at the mandibular foramen. The findings supported malignant involvement of the inferior alveolar nerve and explained the numb-chin syndrome. With distant metastatic disease, her latest stage is Stage IV.

Letrozole was stopped and she started exemestane 25 mg once daily. A chemoport was inserted, and she received further radiotherapy together with monthly zoledronic acid/denosumab for metastatic bone disease. A thoracolumbosacral orthosis was also used because of her spinal condition.

At discharge she remained numb over the left mandible but was walking well without lower-limb pain. Monthly follow-up was planned.