Journal of Medical Imaging and Radiation Oncology 58 (2014) 700–705 bs_bs_banner
RADIATION O N C O LO GY —O R I G I N A L A RTICLE
Numb chin syndrome: A case series of a clinical syndrome associated with malignancy Neetu Tejani,1 Adam Cooper,2 Angela Rezo,1 Gane Pranavan2,3 and Desmond Yip2,3 1 Department of Radiation Oncology and 2Department of Medical Oncology, The Canberra Hospital, and 3ANU Medical School, Australian National University, Canberra, Australian Capital Territory, Australia
N Tejani MBSS; A Cooper MBSS, FRACP; A Rezo FRANZCR, MBBS, BSc(Med); G Pranavan MBBS, FRACP; D Yip MBBS, FRACP. Correspondence Dr Angela Rezo, Department of Radiation Oncology, The Canberra Hospital, Yamba Drive, Garran, ACT 2905, Australia. Email: [email protected] Conflict of interest: None. Submitted 14 November 2013; accepted 4 March 2014. doi:10.1111/1754-9485.12177
Abstract Introduction: Information regarding the appropriate work-up and outcomes in patients receiving palliative treatment for numb chin syndrome (NCS) in the setting of malignancy is sparse. This study aims to describe NCS in malignancy and evaluate the disease trajectory, significance of diagnostic modalities and outcomes with palliative treatment. Methods: A retrospective study was performed on patients presenting with NCS between March 2007 and October 2013 at the Capital Region Cancer Service, Canberra. Results: Thirteen patients were identified who presented with numbness of the chin between March 2007 and October 2013. Seven patients had breast cancer, two had prostate cancer, two had multiple myeloma, one had medulloblastoma and one had an adenoid cystic salivary gland tumour. The mean interval from initial cancer diagnosis to development of the syndrome was 4.32 years. Twelve out of 13 patients had had prior chemotherapy with two or more lines of treatment (with a median of two lines), indicating this condition tended to present late in the course of disease in our patients. Four patients developed bilateral symptoms, and in two of these cases the metastatic lesion was in the base of the skull. Eleven out of 13 patients had positive signs on imaging. Nine out of 13 patients received palliative radiotherapy, with clinical response in eight patients. Conclusion: Patients with malignancy presented with NCS late in the disease trajectory, often after multiple lines of treatment. In our cohort of patients, 84% had positive imaging signs to aid diagnosis, and 77% had resolution of numbness with palliative treatment. Key words: facial numbness; inferior alveolar nerve; mandibular metastasis; mental nerve; numb chin syndrome.
Introduction The numb chin syndrome (NCS) is characterised by sensory changes along the distribution of the inferior alveolar nerve or mental nerve (Fig. 1). It is a seemingly innocuous symptom, but cases in which dental pathology is excluded are frequently associated with cancer. NCS can be a sign of tumour progression or the presenting symptom of a malignancy, or it can be due to benign causes (which is less common).2–4 Clinicians should therefore be aware that the seemingly trivial symptom of lower facial numbness may signal serious pathology. It is an uncommon but well-documented manifestation of metastatic malignancy and was first described in a 700
patient with breast cancer in 1830.5 Any type of malignancy can metastasise to the mandible, although this is a rare event. Adenocarcinoma is the most frequent histological subtype reported.4 The most common primary cancers associated with this syndrome are breast, lung, lymphoma, thyroid, prostate and colon. Bone marrow infiltration of the jaw leading to nerve compression has been proven in cases of lymphoma, acute lymphoblastic leukaemia and multiple myeloma.4 Common symptoms include numbness over the lower lip, chin and gingival mucosa.6 Patients can suffer pain from an expanding metastasis but often do not present with pain. Patients can also develop morbidity from inadvertent biting of the lower lip and may complain of © 2014 The Royal Australian and New Zealand College of Radiologists
Numb chin syndrome
Fig. 1. The mandibular branch of the trigeminal nerve exits the base of skull through the foramen ovale (in the sphenoid) and divides into anterior and posterior trunks. The latter divides into the lingual and inferior alveolar nerves. The inferior alveolar nerve enters the mandibular canal and travels within the mandible. The mental nerve exits at the mandibular foramen (at the level of the canine teeth) and innervates the chin and lower lip.1
difficulty eating with dribbling of food and drink. The discovery of this symptom should alert the clinician to the possibility of disseminated disease and thus help avoid unnecessary delay in the work-up and treatment. Treatment is palliative and mostly involves radiotherapy. Prognosis of NCS in patients with cancer is poor, and median survival after diagnosis is generally less than 1 year.4
Methods We review our experience with patients with this condition treated at the Capital Region Cancer Service in recent years. Clinicians recalled the patient details in a number of cases, and further cases were identified by searching electronic records of correspondence for the terms ‘numb chin’, ‘inferior alveolar nerve’ and ‘mental nerve’. Data were obtained on patient demographics, primary cancer diagnosis, time to onset of symptoms from cancer diagnosis, previous systemic treatments, imaging findings, anatomical site, details of treatment and palliation of symptoms.
Results Thirteen patients were identified (six men and seven women) who presented with numbness of the chin in the presence of cancer between March 2007 and October © 2014 The Royal Australian and New Zealand College of Radiologists
2013. Seven (54%) had breast cancer, two (15%) had prostate cancer, two (15%) had multiple myeloma, one (8%) had medulloblastoma and one (8%) had an adenoid cystic salivary gland tumour. The mean age of patients at the time of development of symptoms was 54 years (range 19–72 years). The median interval from initial cancer diagnosis to development of the syndrome was 4.3 years (range 8 months to 12 years). Twelve out of thirteen patients (92%) had prior chemotherapy with two or more lines of treatment (with a median of two lines), indicating this condition tended to present late in the course of disease. Only two patients were alive at the time of writing of this article. The median survival from diagnosis of NCS was 6 months in our cohort of patients. Four patients (31%) developed bilateral symptoms, and in two of these cases the metastatic lesion was in the base of the skull. Five out of thirteen patients (38%) were referred for dental review, and dental pathology was excluded in all these patients. Dental abscess and osteonecrosis of the jaw were some of the differential diagnoses being considered. The details of the patient demographics, results of investigations and treatments are summarised in Table 1. Eleven out of thirteen patients (85%) had positive imaging examinations. One patient refused imaging, and extensive tests including CT and MRI of the brain and spine failed to reveal the cause in the other patient. The 701
702
Prostate cancer
Breast cancer Breast cancer
Breast cancer Breast cancer Breast cancer Multiple myeloma Multiple myeloma Prostate cancer Medulloblastoma Breast cancer Breast cancer
Adenoid cystic salivary gland tumour
72 (M)
54 (M) 42 (F)
57 (F) 52 (F) 45 (F) 65 (M) 59 (M) 59 (M) 19 (M) 63 (F) 68 (F)
49 (F) 20 months
5 years 8 years 4 years 8 months 13 months 2.5 years 18 months 3.5 years 6 years
2 years 9 years
12 years
Time to onset of numb chin syndrome from initial diagnosis‡
2
3 2 2 2 3 2 0 2 4
4 3
4
Lines of chemotherapy§
No
No No No No Yes No No Yes No
Yes Yes
Yes
Dental review
MRI
CT N/A CT X-ray OPG, CT N/A PET MRI MRI
MRI MRI, WBBS
MRI
Positive imaging modality
Mandible
Mandible with perineural involvement of the inferior alveolar nerve Mandible Left hemimandible Right hemimandible with perineural infiltration of the mandibular branch of the trigeminal nerve Base of skull Unknown Base of skull Mandible Mandible Unknown Mandible Leptomeningeal disease Leptomeningeal disease
Anatomical site
No
Yes No Yes No No No No No No
Yes Yes
No
Bilateral symptoms
RT to L and R mandible RT to L hemimandible RT to R hemimandible and following course of mandibular nerve to base of skull Chemotherapy Chemotherapy RT to base of skull Surgery, RT to L mandible RT to L mandible Chemotherapy RT to Mandible No RT to whole brain and leptomeninges RT to R mandible
RT to left hemimandible and base of skull
Treatment
16 Gy in 8 fractions
N/A N/A 30 Gy in 10 fractions 20 Gy in 5 fractions 20 Gy in 5 fractions N/A 8 Gy in 1 fraction N/A 20 Gy in 5 fractions
20 Gy in 5 fractions 20 Gy in 5 fractions 21 Gy in 7 fractions
20 Gy in 5 fractions
Radiation dose and fractionation
Yes
Yes Yes No Yes Yes No Yes No Yes
Yes Yes
Yes
Palliation of symptoms
†Mean age = 54 years. ‡Mean time to onset = 4.32 years. §Median = 2.5 lines of treatment. N/A, not applicable; OPG, orthopantomogram; PET, positron emission tomography; RT, radiotherapy; WBBS, whole-body bone scan.
Primary diagnosis
Age (sex)†
Table 1. Patient characteristics, cancer details, imaging findings and treatments given
N Tejani et al.
© 2014 The Royal Australian and New Zealand College of Radiologists
Numb chin syndrome
Fig. 2. T1-weighted axial MRI image through the mandible of a patient with breast cancer. The arrow indicates an area of abnormal signal due to a sclerotic metastasis.
causative abnormality was seen on CT scan, bone scan, orthopantomogram (OPG) or fluorodeoxyglucose positron emission tomography (FDG-PET scan) in some cases, but in five cases the lesion was seen only on MRI. Lesions were seen on plain X-rays in the two patients with multiple myeloma. In both cases with metastases in the base of the skull, the lesions were seen on CT scanning. The anatomical sites of metastasis included the base of skull, the mandibular angle and the mandibular body. In one patient, MRI revealed an abnormal signal in the mandible due to sclerotic metastasis (Fig. 2). In one case, infiltration of the inferior alveolar nerve was seen on MRI (Fig. 3). Nine patients (69%) were treated with radiotherapy, and eight showed improvement in numbness. Four
Fig. 4. Isodose distribution curves from the radiotherapy treatment plan of a patient treated with 21 Gy in seven fractions to the right hemimandible.
patients initially presented with or subsequently developed contralateral symptoms. In two cases, this was due to a second metastasis in the contralateral hemimandible, and in two cases it was due to base-ofskull disease. The radiation dose and fractionation delivered varied from 8 Gy in one fraction to 30 Gy in 10 fractions. The most common prescribed schedule was 20 Gy in five fractions using megavoltage photon beams. Figure 4 shows isodose plans of a three-field photon beam arrangement used to treat one of the patients who had disease in the hemimandible causing NCS. Figure 5 is a digitally reconstructed radiograph of a lateral photon field used to treat NCS when the cause was a sclerotic metastasis from breast cancer in the base of the skull. As illustrated in these diagrams, the radiotherapy portals varied depending on the location of the nerve impingement. All patients treated with radiotherapy to the mandible reported some mucositis following treatment, but none went on to develop long-term sequelae such as xerostomia. Two patients treated with palliative chemotherapy also reported improvement in facial numbness.
Discussion
Fig. 3. T1-weighted sagittal MRI image (with contrast) of a patient with prostate cancer. The arrow shows an area of abnormal enhancement in the inferior alveolar nerve due to tumour invasion. © 2014 The Royal Australian and New Zealand College of Radiologists
NCS, or mental nerve neuropathy, is a sensory neuropathy presenting with numbness of the chin in the distribution of the mental nerve and the branches of the mandibular division of the trigeminal nerve. Though it can be caused by a benign process, NCS should be regarded as being due to malignancy until proven otherwise. The diagnosis of NCS is largely clinical; however, various radiographic studies are helpful to confirm 703
N Tejani et al.
Fig. 5. Beam’s eye view of a right lateral photon beam treating the involved inferior alveolar nerve following its course to the base of skull.
diagnosis. Perhaps the most important step in the diagnosis of NCS is recognising the significance of unilateral chin or lip numbness. The mechanism of this syndrome may be peripheral (i.e. metastasis or invasion of the mandible causing compression on the nerve) or central (i.e. due to baseof-skull lesions, leptomeningeal seeding, or perineural or neural invasion), or it may be a paraneoplastic syndrome. In the largest series of NCS reported in the literature, by Lossos et al., the aetiology was identified as bone metastases in the mandible in 50% of cases, metastases in the base of the skull in 14% of cases and leptomeningeal seeding in 22% of cases and was unidentified in the remaining cases.7 If the syndrome is caused by a base-of-skull lesion it may be associated with other signs, such as sixth- or seventh-nerve palsies, and if leptomeningeal seeding is the cause, the syndrome is often followed by multiple cranial nerve palsies.4 This study’s findings are similar to those of previously published papers and are consistent with larger series. NCS can also have benign causes, such as periapical inflammation, cysts, benign tumours and fracture of the craniofacial region.8 In the non-oncological setting, these patients present to general practitioners and dentists. NCS is rare in the general population, and metastasis causing NCS occurs in
RADIATION O N C O LO GY —O R I G I N A L A RTICLE
Numb chin syndrome: A case series of a clinical syndrome associated with malignancy Neetu Tejani,1 Adam Cooper,2 Angela Rezo,1 Gane Pranavan2,3 and Desmond Yip2,3 1 Department of Radiation Oncology and 2Department of Medical Oncology, The Canberra Hospital, and 3ANU Medical School, Australian National University, Canberra, Australian Capital Territory, Australia
N Tejani MBSS; A Cooper MBSS, FRACP; A Rezo FRANZCR, MBBS, BSc(Med); G Pranavan MBBS, FRACP; D Yip MBBS, FRACP. Correspondence Dr Angela Rezo, Department of Radiation Oncology, The Canberra Hospital, Yamba Drive, Garran, ACT 2905, Australia. Email: [email protected] Conflict of interest: None. Submitted 14 November 2013; accepted 4 March 2014. doi:10.1111/1754-9485.12177
Abstract Introduction: Information regarding the appropriate work-up and outcomes in patients receiving palliative treatment for numb chin syndrome (NCS) in the setting of malignancy is sparse. This study aims to describe NCS in malignancy and evaluate the disease trajectory, significance of diagnostic modalities and outcomes with palliative treatment. Methods: A retrospective study was performed on patients presenting with NCS between March 2007 and October 2013 at the Capital Region Cancer Service, Canberra. Results: Thirteen patients were identified who presented with numbness of the chin between March 2007 and October 2013. Seven patients had breast cancer, two had prostate cancer, two had multiple myeloma, one had medulloblastoma and one had an adenoid cystic salivary gland tumour. The mean interval from initial cancer diagnosis to development of the syndrome was 4.32 years. Twelve out of 13 patients had had prior chemotherapy with two or more lines of treatment (with a median of two lines), indicating this condition tended to present late in the course of disease in our patients. Four patients developed bilateral symptoms, and in two of these cases the metastatic lesion was in the base of the skull. Eleven out of 13 patients had positive signs on imaging. Nine out of 13 patients received palliative radiotherapy, with clinical response in eight patients. Conclusion: Patients with malignancy presented with NCS late in the disease trajectory, often after multiple lines of treatment. In our cohort of patients, 84% had positive imaging signs to aid diagnosis, and 77% had resolution of numbness with palliative treatment. Key words: facial numbness; inferior alveolar nerve; mandibular metastasis; mental nerve; numb chin syndrome.
Introduction The numb chin syndrome (NCS) is characterised by sensory changes along the distribution of the inferior alveolar nerve or mental nerve (Fig. 1). It is a seemingly innocuous symptom, but cases in which dental pathology is excluded are frequently associated with cancer. NCS can be a sign of tumour progression or the presenting symptom of a malignancy, or it can be due to benign causes (which is less common).2–4 Clinicians should therefore be aware that the seemingly trivial symptom of lower facial numbness may signal serious pathology. It is an uncommon but well-documented manifestation of metastatic malignancy and was first described in a 700
patient with breast cancer in 1830.5 Any type of malignancy can metastasise to the mandible, although this is a rare event. Adenocarcinoma is the most frequent histological subtype reported.4 The most common primary cancers associated with this syndrome are breast, lung, lymphoma, thyroid, prostate and colon. Bone marrow infiltration of the jaw leading to nerve compression has been proven in cases of lymphoma, acute lymphoblastic leukaemia and multiple myeloma.4 Common symptoms include numbness over the lower lip, chin and gingival mucosa.6 Patients can suffer pain from an expanding metastasis but often do not present with pain. Patients can also develop morbidity from inadvertent biting of the lower lip and may complain of © 2014 The Royal Australian and New Zealand College of Radiologists
Numb chin syndrome
Fig. 1. The mandibular branch of the trigeminal nerve exits the base of skull through the foramen ovale (in the sphenoid) and divides into anterior and posterior trunks. The latter divides into the lingual and inferior alveolar nerves. The inferior alveolar nerve enters the mandibular canal and travels within the mandible. The mental nerve exits at the mandibular foramen (at the level of the canine teeth) and innervates the chin and lower lip.1
difficulty eating with dribbling of food and drink. The discovery of this symptom should alert the clinician to the possibility of disseminated disease and thus help avoid unnecessary delay in the work-up and treatment. Treatment is palliative and mostly involves radiotherapy. Prognosis of NCS in patients with cancer is poor, and median survival after diagnosis is generally less than 1 year.4
Methods We review our experience with patients with this condition treated at the Capital Region Cancer Service in recent years. Clinicians recalled the patient details in a number of cases, and further cases were identified by searching electronic records of correspondence for the terms ‘numb chin’, ‘inferior alveolar nerve’ and ‘mental nerve’. Data were obtained on patient demographics, primary cancer diagnosis, time to onset of symptoms from cancer diagnosis, previous systemic treatments, imaging findings, anatomical site, details of treatment and palliation of symptoms.
Results Thirteen patients were identified (six men and seven women) who presented with numbness of the chin in the presence of cancer between March 2007 and October © 2014 The Royal Australian and New Zealand College of Radiologists
2013. Seven (54%) had breast cancer, two (15%) had prostate cancer, two (15%) had multiple myeloma, one (8%) had medulloblastoma and one (8%) had an adenoid cystic salivary gland tumour. The mean age of patients at the time of development of symptoms was 54 years (range 19–72 years). The median interval from initial cancer diagnosis to development of the syndrome was 4.3 years (range 8 months to 12 years). Twelve out of thirteen patients (92%) had prior chemotherapy with two or more lines of treatment (with a median of two lines), indicating this condition tended to present late in the course of disease. Only two patients were alive at the time of writing of this article. The median survival from diagnosis of NCS was 6 months in our cohort of patients. Four patients (31%) developed bilateral symptoms, and in two of these cases the metastatic lesion was in the base of the skull. Five out of thirteen patients (38%) were referred for dental review, and dental pathology was excluded in all these patients. Dental abscess and osteonecrosis of the jaw were some of the differential diagnoses being considered. The details of the patient demographics, results of investigations and treatments are summarised in Table 1. Eleven out of thirteen patients (85%) had positive imaging examinations. One patient refused imaging, and extensive tests including CT and MRI of the brain and spine failed to reveal the cause in the other patient. The 701
702
Prostate cancer
Breast cancer Breast cancer
Breast cancer Breast cancer Breast cancer Multiple myeloma Multiple myeloma Prostate cancer Medulloblastoma Breast cancer Breast cancer
Adenoid cystic salivary gland tumour
72 (M)
54 (M) 42 (F)
57 (F) 52 (F) 45 (F) 65 (M) 59 (M) 59 (M) 19 (M) 63 (F) 68 (F)
49 (F) 20 months
5 years 8 years 4 years 8 months 13 months 2.5 years 18 months 3.5 years 6 years
2 years 9 years
12 years
Time to onset of numb chin syndrome from initial diagnosis‡
2
3 2 2 2 3 2 0 2 4
4 3
4
Lines of chemotherapy§
No
No No No No Yes No No Yes No
Yes Yes
Yes
Dental review
MRI
CT N/A CT X-ray OPG, CT N/A PET MRI MRI
MRI MRI, WBBS
MRI
Positive imaging modality
Mandible
Mandible with perineural involvement of the inferior alveolar nerve Mandible Left hemimandible Right hemimandible with perineural infiltration of the mandibular branch of the trigeminal nerve Base of skull Unknown Base of skull Mandible Mandible Unknown Mandible Leptomeningeal disease Leptomeningeal disease
Anatomical site
No
Yes No Yes No No No No No No
Yes Yes
No
Bilateral symptoms
RT to L and R mandible RT to L hemimandible RT to R hemimandible and following course of mandibular nerve to base of skull Chemotherapy Chemotherapy RT to base of skull Surgery, RT to L mandible RT to L mandible Chemotherapy RT to Mandible No RT to whole brain and leptomeninges RT to R mandible
RT to left hemimandible and base of skull
Treatment
16 Gy in 8 fractions
N/A N/A 30 Gy in 10 fractions 20 Gy in 5 fractions 20 Gy in 5 fractions N/A 8 Gy in 1 fraction N/A 20 Gy in 5 fractions
20 Gy in 5 fractions 20 Gy in 5 fractions 21 Gy in 7 fractions
20 Gy in 5 fractions
Radiation dose and fractionation
Yes
Yes Yes No Yes Yes No Yes No Yes
Yes Yes
Yes
Palliation of symptoms
†Mean age = 54 years. ‡Mean time to onset = 4.32 years. §Median = 2.5 lines of treatment. N/A, not applicable; OPG, orthopantomogram; PET, positron emission tomography; RT, radiotherapy; WBBS, whole-body bone scan.
Primary diagnosis
Age (sex)†
Table 1. Patient characteristics, cancer details, imaging findings and treatments given
N Tejani et al.
© 2014 The Royal Australian and New Zealand College of Radiologists
Numb chin syndrome
Fig. 2. T1-weighted axial MRI image through the mandible of a patient with breast cancer. The arrow indicates an area of abnormal signal due to a sclerotic metastasis.
causative abnormality was seen on CT scan, bone scan, orthopantomogram (OPG) or fluorodeoxyglucose positron emission tomography (FDG-PET scan) in some cases, but in five cases the lesion was seen only on MRI. Lesions were seen on plain X-rays in the two patients with multiple myeloma. In both cases with metastases in the base of the skull, the lesions were seen on CT scanning. The anatomical sites of metastasis included the base of skull, the mandibular angle and the mandibular body. In one patient, MRI revealed an abnormal signal in the mandible due to sclerotic metastasis (Fig. 2). In one case, infiltration of the inferior alveolar nerve was seen on MRI (Fig. 3). Nine patients (69%) were treated with radiotherapy, and eight showed improvement in numbness. Four
Fig. 4. Isodose distribution curves from the radiotherapy treatment plan of a patient treated with 21 Gy in seven fractions to the right hemimandible.
patients initially presented with or subsequently developed contralateral symptoms. In two cases, this was due to a second metastasis in the contralateral hemimandible, and in two cases it was due to base-ofskull disease. The radiation dose and fractionation delivered varied from 8 Gy in one fraction to 30 Gy in 10 fractions. The most common prescribed schedule was 20 Gy in five fractions using megavoltage photon beams. Figure 4 shows isodose plans of a three-field photon beam arrangement used to treat one of the patients who had disease in the hemimandible causing NCS. Figure 5 is a digitally reconstructed radiograph of a lateral photon field used to treat NCS when the cause was a sclerotic metastasis from breast cancer in the base of the skull. As illustrated in these diagrams, the radiotherapy portals varied depending on the location of the nerve impingement. All patients treated with radiotherapy to the mandible reported some mucositis following treatment, but none went on to develop long-term sequelae such as xerostomia. Two patients treated with palliative chemotherapy also reported improvement in facial numbness.
Discussion
Fig. 3. T1-weighted sagittal MRI image (with contrast) of a patient with prostate cancer. The arrow shows an area of abnormal enhancement in the inferior alveolar nerve due to tumour invasion. © 2014 The Royal Australian and New Zealand College of Radiologists
NCS, or mental nerve neuropathy, is a sensory neuropathy presenting with numbness of the chin in the distribution of the mental nerve and the branches of the mandibular division of the trigeminal nerve. Though it can be caused by a benign process, NCS should be regarded as being due to malignancy until proven otherwise. The diagnosis of NCS is largely clinical; however, various radiographic studies are helpful to confirm 703
N Tejani et al.
Fig. 5. Beam’s eye view of a right lateral photon beam treating the involved inferior alveolar nerve following its course to the base of skull.
diagnosis. Perhaps the most important step in the diagnosis of NCS is recognising the significance of unilateral chin or lip numbness. The mechanism of this syndrome may be peripheral (i.e. metastasis or invasion of the mandible causing compression on the nerve) or central (i.e. due to baseof-skull lesions, leptomeningeal seeding, or perineural or neural invasion), or it may be a paraneoplastic syndrome. In the largest series of NCS reported in the literature, by Lossos et al., the aetiology was identified as bone metastases in the mandible in 50% of cases, metastases in the base of the skull in 14% of cases and leptomeningeal seeding in 22% of cases and was unidentified in the remaining cases.7 If the syndrome is caused by a base-of-skull lesion it may be associated with other signs, such as sixth- or seventh-nerve palsies, and if leptomeningeal seeding is the cause, the syndrome is often followed by multiple cranial nerve palsies.4 This study’s findings are similar to those of previously published papers and are consistent with larger series. NCS can also have benign causes, such as periapical inflammation, cysts, benign tumours and fracture of the craniofacial region.8 In the non-oncological setting, these patients present to general practitioners and dentists. NCS is rare in the general population, and metastasis causing NCS occurs in
