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Numb Chin Syndrome: A Case Report
Vol. 51 No. 1 January 2016
Journal of Pain and Symptom Management
e3
Letter
Numb Chin Syndrome: A Case Report To the Editor: The seemingly innocuous symptom of a numb chin may represent ominous underlying pathology. Although numb chin syndrome may occur in the absence of malignant disease, its presentation should ordinarily prompt a search for a new or progressive known malignancy.1 Charles Bell noted mental anesthesia among patients with jaw trauma and retromandibular tumors in 1930, and the link with systemic malignancy was identified by Roger and Pillas in 1937.2 It was named the ‘‘syndrome of the numb chin’’ by Calverley and Mohnac in 1963.3 In the context of severe symptom burden commonly associated with progressive malignant disease, its multiple treatments, and various other comorbidities, the significance of numb chin syndrome may not be readily appreciated by the patient or health care professionals. We present the case of a 55-yearold woman who presented with a numb chin that was initially attributed to dental caries.
Coincidentally, she was admitted to our specialist palliative care service for assessment and management of her bone pain. Magnetic resonance imaging (MRI) studies of her brain and spinal cord confirmed progression of her spinal metastases, but without any neural encroachment. Incidental note was made of a 5 mm lesion in the cerebellar vermis, but this was not thought to be of relevance to her symptoms. A radiograph of her mandible demonstrated sclerotic foci in the left body of mandible and subtle sclerotic foci in the medial aspect of the right body of mandible (Fig. 1). On review of her recent spine MRI, there was heterogeneous decreased T1 signal within the mandible on the sagittal cervical spine imaging, which had not been noted on the initial report. The appearance was in keeping with osseous metastatic disease and was consistent with her overall disease progression. Thus, her symptom of chin and lower lip numbness was explained by the finding of metastatic disease involving her mandible bilaterally, with consequent involvement of the mental nerve.
Comment Case Description A. B. is a married woman with a five-year history of estrogen receptorepositive, human epidermal receptor 2enegative metastatic lobular breast cancer. Her initial treatment included mastectomy, adjuvant radiotherapy, and hormonal therapy. Three years later, she developed bone metastases, which prompted a switch in her hormonal therapy and the introduction of bisphosphonates. She subsequently progressed to develop liver and gastric metastases, and she remains under active medical oncology care and surveillance. The patient has multiple concurrent medical problems including lichen planus. This involves her esophagus, vulva, and ureter and requires regular esophageal dilations. She also has diabetes mellitus, macular degeneration, and depression. A. B. reported new onset bilateral chin numbness over a two-week period without any associated motor signs. An oral health review identified dental caries, and a management plan was developed. Ó 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.
The symptoms of numb chin syndrome are typically associated with damage to the inferior alveolar nerve in the mandible. This nerve is purely sensory and serves the lower lip, chin, lower gingiva, and teeth. The inferior alveolar nerve, as a branch of the mandibular nerve V3, exits the mental foramen after which it becomes the mental nerve. However, the origin of the nerve damage may be peripheral or central. Mechanisms of neural damage include compression of the mental nerve by metastases to the jaw, intracranial involvement of the mandibular nerve by base of skull metastases, leptomeningeal seeding, and neoplastic perineural infiltration of the mental nerve.4 Early and radiologically undetectable bone marrow infiltration is another possible cause.5 The numbness is more commonly unilateral but may be bilateral as illustrated by our case report. Pain is a rare symptom although there may be lesions caused by biting of the lower lip. Not surprisingly, patients frequently present initially to oral health professionals with this symptom. There can be obvious 0885-3924/$ - see front matter
e4
Letter
Vol. 51 No. 1 January 2016
particularly troubled by her symptom of numb chin and has elected not to pursue any specific targeted interventions such as radiotherapy at this time. Her medical oncology management is under regular review. She remains under shared medical oncology and palliative care surveillance.
Fig. 1. Orthopantomogram with scattered sclerotic metastatic foci (marked with white arrows).
dental findings such as cavities, infections, poor retention of dental prosthesis, surgery of impacted teeth, and diseases of the dental apices affecting the inferior alveolar nerve. However, this should not prevent further investigation, as illustrated by our case. Numb chin syndrome precedes a diagnosis of malignancy in up to 47% of cases.6 It is most commonly associated with metastatic breast cancer and lymphoma, followed by prostate cancer, lung cancer, and leukemia. Nonmalignant diseases such as multiple sclerosis, diabetes mellitus, temporal arteritis, systemic amyloidosis, sarcoidosis, and HIV can cause a similar syndrome. Treatment options will depend on the site of the metastatic disease. Patients who present with a numb chin need investigation for bone metastases, intracranial metastases, and leptomeningeal disease with bone scan, plain radiographs, brain MRI, and cerebrospinal fluid analysis. A standard brain MRI does not cover the oromandibular area where the inferior alveolar nerve and mental nerve are located. Targeted imaging such as a mandibular MRI should be considered to localize lesions when there is strong suspicion.7 The symptom is indicative of a very poor prognosis, whether it is a first manifestation of an incipient systemic cancer or a symptom of spread of an already established tumor. In a systematic review of 16 studies involving 129 patients, a mortality of 79% was found, with a weighted mean survival of 6.9 months.8 Only 15% of patients who present with numb chin syndrome survive more than nine months.6
Case Follow-Up Our patient continues on chemotherapy for treatment of her metastatic breast cancer. General pain management strategies have proved quite successful. After discussion, the patient reported that she is not
Bernadette Brady, MB, BAO, BCh, MRCPI, MSc Anne-Marie Coughlan, MB, BAO, BCh Marymount University Hospital & Hospice Cork, Ireland E-mail: [email protected] Tony O’Brien, MB, BAO, BCh, FRCPI Marymount University Hospital & Hospice University College Cork Cork, Ireland http://dx.doi.org/10.1016/j.jpainsymman.2015.10.007
Disclosures and Acknowledgments The authors thank A. B. for giving us permission to present her case, and Dr. Stephen Power, Department of Radiology, Cork University Hospital, for assisting us with radiological imaging.
References 1. Burt R, Sharfman W, Karp B, Wilson W. Mental neuropathy (numb chin syndrome): a harbinger of tumor progression or relapse. Cancer 1992;70:877e881. 2. Lata J, Kumar P. Numb chin syndrome: a case report and review of the literature. Indian J Dent Res 2010;21: 135e137. 3. Calverley JR, Mohnac AM. Syndrome of the numb chin. Arch Intern Med 1963;112:819e821. 4. Lossos A, Siegal T. Numb chin syndrome in cancer patients: etiology, response to treatment, and prognostic significance. Neurology 1992;42:1181e1184. 5. Sanchis JM, Bagan JV, Murillo J, et al. Mental neuropathy as a manifestation associated with malignant processes: its significance in relation to patient survival. J Oral Maxillofac Surg 2008;66:995e998. 6. Ryba F, Rice S, Hutchinson IL. Numb chin syndrome: an ominous clinical sign. Br Dent J 2010;208:283e285. 7. Kim T-W, Park J-W, Kim J-S. A pitfall of brain MRI in evaluation of numb chin syndrome: mandibular MRI should be included to localize lesions. J Neurol Sci 2014;345: 265e266. 8. Gil SG, Diago MP, Diago MP. Malignant mental neuropathy: systematic review. Med Oral Patol Oral Cir Bucal 2008; 13:616e621.
Journal of Pain and Symptom Management
e3
Letter
Numb Chin Syndrome: A Case Report To the Editor: The seemingly innocuous symptom of a numb chin may represent ominous underlying pathology. Although numb chin syndrome may occur in the absence of malignant disease, its presentation should ordinarily prompt a search for a new or progressive known malignancy.1 Charles Bell noted mental anesthesia among patients with jaw trauma and retromandibular tumors in 1930, and the link with systemic malignancy was identified by Roger and Pillas in 1937.2 It was named the ‘‘syndrome of the numb chin’’ by Calverley and Mohnac in 1963.3 In the context of severe symptom burden commonly associated with progressive malignant disease, its multiple treatments, and various other comorbidities, the significance of numb chin syndrome may not be readily appreciated by the patient or health care professionals. We present the case of a 55-yearold woman who presented with a numb chin that was initially attributed to dental caries.
Coincidentally, she was admitted to our specialist palliative care service for assessment and management of her bone pain. Magnetic resonance imaging (MRI) studies of her brain and spinal cord confirmed progression of her spinal metastases, but without any neural encroachment. Incidental note was made of a 5 mm lesion in the cerebellar vermis, but this was not thought to be of relevance to her symptoms. A radiograph of her mandible demonstrated sclerotic foci in the left body of mandible and subtle sclerotic foci in the medial aspect of the right body of mandible (Fig. 1). On review of her recent spine MRI, there was heterogeneous decreased T1 signal within the mandible on the sagittal cervical spine imaging, which had not been noted on the initial report. The appearance was in keeping with osseous metastatic disease and was consistent with her overall disease progression. Thus, her symptom of chin and lower lip numbness was explained by the finding of metastatic disease involving her mandible bilaterally, with consequent involvement of the mental nerve.
Comment Case Description A. B. is a married woman with a five-year history of estrogen receptorepositive, human epidermal receptor 2enegative metastatic lobular breast cancer. Her initial treatment included mastectomy, adjuvant radiotherapy, and hormonal therapy. Three years later, she developed bone metastases, which prompted a switch in her hormonal therapy and the introduction of bisphosphonates. She subsequently progressed to develop liver and gastric metastases, and she remains under active medical oncology care and surveillance. The patient has multiple concurrent medical problems including lichen planus. This involves her esophagus, vulva, and ureter and requires regular esophageal dilations. She also has diabetes mellitus, macular degeneration, and depression. A. B. reported new onset bilateral chin numbness over a two-week period without any associated motor signs. An oral health review identified dental caries, and a management plan was developed. Ó 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.
The symptoms of numb chin syndrome are typically associated with damage to the inferior alveolar nerve in the mandible. This nerve is purely sensory and serves the lower lip, chin, lower gingiva, and teeth. The inferior alveolar nerve, as a branch of the mandibular nerve V3, exits the mental foramen after which it becomes the mental nerve. However, the origin of the nerve damage may be peripheral or central. Mechanisms of neural damage include compression of the mental nerve by metastases to the jaw, intracranial involvement of the mandibular nerve by base of skull metastases, leptomeningeal seeding, and neoplastic perineural infiltration of the mental nerve.4 Early and radiologically undetectable bone marrow infiltration is another possible cause.5 The numbness is more commonly unilateral but may be bilateral as illustrated by our case report. Pain is a rare symptom although there may be lesions caused by biting of the lower lip. Not surprisingly, patients frequently present initially to oral health professionals with this symptom. There can be obvious 0885-3924/$ - see front matter
e4
Letter
Vol. 51 No. 1 January 2016
particularly troubled by her symptom of numb chin and has elected not to pursue any specific targeted interventions such as radiotherapy at this time. Her medical oncology management is under regular review. She remains under shared medical oncology and palliative care surveillance.
Fig. 1. Orthopantomogram with scattered sclerotic metastatic foci (marked with white arrows).
dental findings such as cavities, infections, poor retention of dental prosthesis, surgery of impacted teeth, and diseases of the dental apices affecting the inferior alveolar nerve. However, this should not prevent further investigation, as illustrated by our case. Numb chin syndrome precedes a diagnosis of malignancy in up to 47% of cases.6 It is most commonly associated with metastatic breast cancer and lymphoma, followed by prostate cancer, lung cancer, and leukemia. Nonmalignant diseases such as multiple sclerosis, diabetes mellitus, temporal arteritis, systemic amyloidosis, sarcoidosis, and HIV can cause a similar syndrome. Treatment options will depend on the site of the metastatic disease. Patients who present with a numb chin need investigation for bone metastases, intracranial metastases, and leptomeningeal disease with bone scan, plain radiographs, brain MRI, and cerebrospinal fluid analysis. A standard brain MRI does not cover the oromandibular area where the inferior alveolar nerve and mental nerve are located. Targeted imaging such as a mandibular MRI should be considered to localize lesions when there is strong suspicion.7 The symptom is indicative of a very poor prognosis, whether it is a first manifestation of an incipient systemic cancer or a symptom of spread of an already established tumor. In a systematic review of 16 studies involving 129 patients, a mortality of 79% was found, with a weighted mean survival of 6.9 months.8 Only 15% of patients who present with numb chin syndrome survive more than nine months.6
Case Follow-Up Our patient continues on chemotherapy for treatment of her metastatic breast cancer. General pain management strategies have proved quite successful. After discussion, the patient reported that she is not
Bernadette Brady, MB, BAO, BCh, MRCPI, MSc Anne-Marie Coughlan, MB, BAO, BCh Marymount University Hospital & Hospice Cork, Ireland E-mail: [email protected] Tony O’Brien, MB, BAO, BCh, FRCPI Marymount University Hospital & Hospice University College Cork Cork, Ireland http://dx.doi.org/10.1016/j.jpainsymman.2015.10.007
Disclosures and Acknowledgments The authors thank A. B. for giving us permission to present her case, and Dr. Stephen Power, Department of Radiology, Cork University Hospital, for assisting us with radiological imaging.
References 1. Burt R, Sharfman W, Karp B, Wilson W. Mental neuropathy (numb chin syndrome): a harbinger of tumor progression or relapse. Cancer 1992;70:877e881. 2. Lata J, Kumar P. Numb chin syndrome: a case report and review of the literature. Indian J Dent Res 2010;21: 135e137. 3. Calverley JR, Mohnac AM. Syndrome of the numb chin. Arch Intern Med 1963;112:819e821. 4. Lossos A, Siegal T. Numb chin syndrome in cancer patients: etiology, response to treatment, and prognostic significance. Neurology 1992;42:1181e1184. 5. Sanchis JM, Bagan JV, Murillo J, et al. Mental neuropathy as a manifestation associated with malignant processes: its significance in relation to patient survival. J Oral Maxillofac Surg 2008;66:995e998. 6. Ryba F, Rice S, Hutchinson IL. Numb chin syndrome: an ominous clinical sign. Br Dent J 2010;208:283e285. 7. Kim T-W, Park J-W, Kim J-S. A pitfall of brain MRI in evaluation of numb chin syndrome: mandibular MRI should be included to localize lesions. J Neurol Sci 2014;345: 265e266. 8. Gil SG, Diago MP, Diago MP. Malignant mental neuropathy: systematic review. Med Oral Patol Oral Cir Bucal 2008; 13:616e621.