Numb chin syndrome associated with metastatic invasive ductal carcinoma of breast

Numb chin syndrome (NCS), also known as mental nerve neuropathy, is characterized by facial and oral numbness restricted to the distribution of the mental nerve. Although not a common neuropathy, the clinical importance of this syndrome is its frequent association with malignancies. A 56-year-old Indian female reported with a complaint of numbness on the left side of chin. She had undergone a radical mastectomy with axillary lymph node dissection for invasive ductal carcinoma of the right breast 4 years ago. Biopsy revealed tumor cells showing pleomorphic hyperchromatic nuclei arranged in cord and nests leading to a diagnosis of metastatic carcinoma of breast origin. Bone scan showed increased uptake in multiple areas in skull, left hemimandible, multiple vertebrae, multiple ribs on either sides, right clavicle both scapulae and sternum, both humeri, multiple pelvic bones and trochanteric region of left femur. The patient was referred to a tertiary cancer institute where she received palliative hormonal and chemotherapy, which helped with her pain and halted the progression of the metastatic disease for past 22 months. The present case depicts the importance of proper recognition of NCS as it may often be the only symptom of an underlying malignancy or the first evidence of dissemination from a primary site as evident in this case.