Journal of the Neurological Sciences 345 (2014) 265–266
Contents lists available at ScienceDirect
Journal of the Neurological Sciences journal homepage: www.elsevier.com/locate/jns
Letter to the Editor A pitfall of brain MRI in evaluation of numb chin syndrome: Mandibular MRI should be included to localize lesions Keywords: Numb chin syndrome Mandible Brain Cancer Metastasis Magnetic resonance imaging
Dear Editor Numb chin syndrome (NCS) refers to abnormal sensation in the chin and lower lip within the mental nerve distribution. NCS is caused by malignant infiltration of the inferior alveolar nerve or the mental nerve and its branches, or through compression of these nerves by jaw metastases or local tumors [1]. This syndrome sometimes presents as the first symptom of metastasis, and therefore requires prompt and accurate diagnosis. However, its diagnosis can be difficult due to the low sensitivity of imaging studies such as computed tomography (CT), panoramic radiography of the jaw or bone scan [2–5]. In addition, routine brain magnetic resonance imaging (MRI) may give false negative results in skull base and maxillo-mandibular lesions. We present a series of three consecutive patients with NCS. Dental problems were excluded in all patients. Two patients had been diagnosed with hematologic cancer, and one with breast cancer. Numb chin syndrome in these patients was accurately diagnosed by oromandibular MRI after other imaging tools failed to diagnose the condition or after it had been evaluated using routine brain MRI. 1. Case series 1.1. Patient 1 A 56-year-old woman previously diagnosed with multiple myeloma presented with numbness of the right chin. An oncologist ordered a brain MRI and no corresponding lesion was found; however, these MRI sequences did not cover the oromandibular area where the inferior alveolar nerve and mental nerve are located. A corresponding lesion was also not found on bone scan or panoramic radiography of the jaw, either. We performed MRI of the mandible area, which demonstrated a contrast-enhancing lesion of the right mandibular bone suggestive of multiple myeloma involvement (Fig. 1A–C).
mandible area. We performed MRI of the mandible area and found contrast-enhancing lesions suggestive of breast cancer metastasis to the mandible bone (Fig. 1D, E). 1.3. Patients 3 An 18-year-old man with acute myeloid leukemia presented with a 3-month history of numbness and paresthesia of the left lower lip and chin. On evaluation, there were no abnormalities in the mandible area on skull base CT, enhancement brain MRI and panoramic radiography of the jaw. MRI of mandible area revealed a contrast-enhancing lesion of the left mandible bone suggestive of leukemic infiltration (Fig. 1F). 2. Discussion In patients with NCS, affected localized areas that could result in isolated chin or lower lip sensory changes are very limited, and most affecting lesions found on the inferior alveolar or mental nerves or these branches in the mandible. In addition, skull base lesions involving the pathways of the mandible branches of the trigeminal nerve such as Meckel's cave or the foramen ovale also represent candidate pathologies. In contrast, axial brain lesions including supratentorial or infratentorial parenchymal lesions are uncommonly to be associated with these isolated symptoms. Nevertheless many neurologists and oncologists perform routine enhancement brain MRI and this is arguably indicated anyway, to examine for other causes such as leptomeningeal metastasis. Thus, abnormalities are not found on imaging studies, despite comprehensive evaluation of the whole brain [3,4,6–8]. Routine brain MRI does not cover the mandible area, which is the most common location of metastatic lesions causing NCS [9]. In addition, mandibular MRI could detect contrast-enhancing soft tissue lesions that were not apparent on panoramic X-ray, CT or bone scan. Therefore, we suggest that the clinicians should include the mandible to detect metastatic lesions in patients with NCS. Since a prompt diagnosis can significantly improve treatment course and prognosis, recognizing the potential clinical significance of unilateral chin or lip numbness is critical. This report presents further examples for the importance of appropriate imaging in NCS patients and suggests that physicians should employ oromandibular MRI in addition to brain MRI. Conflict of interest The authors have no conflicts of interest to disclose. References
1.2. Patient 2 A 65-year-old woman with breast cancer presented with numbness of the left chin and lower lip. Another oncologist performed brain MRI and no corresponding lesion was found, but this MRI did not cover the
http://dx.doi.org/10.1016/j.jns.2014.07.029 0022-510X/© 2014 Elsevier B.V. All rights reserved.
[1] Laurencet FM, Anchisi S, Tullen E, Dietrich PY. Mental neuropathy: report of five cases and review of the literature. Crit Rev Oncol Hematol 2000;34:71–9. [2] Friedrich RE. Mental neuropathy (numb chin syndrome) leading to diagnosis of metastatic mediastinal cancer. Anticancer Res 2010;30:1819–21. [3] Fan Y, Luka R, Noronha A. Non-Hodgkin lymphoma presenting with numb chin syndrome. BMJ Case Rep 2011. http://dx.doi.org/10.1136/bcr.01.2011.3712.
266
Letter to the Editor
Fig. 1. (Patient 1) The scan lines of midsagittal scout view of routine brain magnetic resonance imaging (MRI) (A); it could not cover the mandible, which is the most common location of metastatic lesions causing numb chin syndrome. The scan lines of midsagittal scout view of mandibular MRI (B); contrast enhanced T1-weighted fat suppression sequence revealed an enhancing lesion (white arrow) of the right mandible (C). (Patient 2) Contrast enhanced T1-weighted fat suppression mandibular MRI showed enhancing masses (white arrows) of the bilateral mandible (D and E), which were not shown on computed tomography. (Patient 3) Contrast enhanced T1-weighted fat suppression mandibular MRI demonstrated an enhancing lesion (white arrow) of the left mandible (F). This lesion was not found on skull base computed tomography or panoramic radiography of the jaw.
[4] Seymour JF, Rodriguez MA. Mental neuropathy (numb chin syndrome): a harbinger of tumor progression or relapse. Cancer 1993;71:874–5. [5] Baskaran RK, Krishnamoorthy, Smith M. Numb chin syndrome—a reflection of systemic malignancy. World J Surg Oncol 2006;4:52. [6] Zaheer F, Hussain K, Rao J. Unusual presentation of ‘numb chin syndrome’ as the manifestation of metastatic adenocarcinoma of the lung. Int J Surg Case Rep 2013;4:1097–9. [7] Jenkins RW, McDonald K, Greenberg CS. Numb chin syndrome in acute myeloid leukemia. Am J Med Sci 2012;344:237–40. [8] Sasaki M, Yamazaki H, Aoki T, Papadhimitriou S, Paterakis G, Stiakakki E, et al. Bilateral numb chin syndrome leading to a diagnosis of Burkitt's cell acute lymphocytic leukemia: a case report and literature review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;111:e11–6. [9] Assaf AT, Jürgens TP, Benecke AW, Riecke B, Blessmann M, Zrnc TA, et al. Numb chin syndrome: a rare and often overlooked symptom. J Oral Facial Pain Headache 2014;28:80–90.
Tae-Won Kim Jeong-Wook Park Joong-Seok Kim⁎ ⁎Corresponding author at: Department of Neurology, Seoul St. Mary's Hospital, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul 137-701, Republic of Korea. Tel.: +82 2 2258 6078; fax: +82 2 599 9686. E-mail address: [email protected] (J.-S. Kim). 6 May 2014
Contents lists available at ScienceDirect
Journal of the Neurological Sciences journal homepage: www.elsevier.com/locate/jns
Letter to the Editor A pitfall of brain MRI in evaluation of numb chin syndrome: Mandibular MRI should be included to localize lesions Keywords: Numb chin syndrome Mandible Brain Cancer Metastasis Magnetic resonance imaging
Dear Editor Numb chin syndrome (NCS) refers to abnormal sensation in the chin and lower lip within the mental nerve distribution. NCS is caused by malignant infiltration of the inferior alveolar nerve or the mental nerve and its branches, or through compression of these nerves by jaw metastases or local tumors [1]. This syndrome sometimes presents as the first symptom of metastasis, and therefore requires prompt and accurate diagnosis. However, its diagnosis can be difficult due to the low sensitivity of imaging studies such as computed tomography (CT), panoramic radiography of the jaw or bone scan [2–5]. In addition, routine brain magnetic resonance imaging (MRI) may give false negative results in skull base and maxillo-mandibular lesions. We present a series of three consecutive patients with NCS. Dental problems were excluded in all patients. Two patients had been diagnosed with hematologic cancer, and one with breast cancer. Numb chin syndrome in these patients was accurately diagnosed by oromandibular MRI after other imaging tools failed to diagnose the condition or after it had been evaluated using routine brain MRI. 1. Case series 1.1. Patient 1 A 56-year-old woman previously diagnosed with multiple myeloma presented with numbness of the right chin. An oncologist ordered a brain MRI and no corresponding lesion was found; however, these MRI sequences did not cover the oromandibular area where the inferior alveolar nerve and mental nerve are located. A corresponding lesion was also not found on bone scan or panoramic radiography of the jaw, either. We performed MRI of the mandible area, which demonstrated a contrast-enhancing lesion of the right mandibular bone suggestive of multiple myeloma involvement (Fig. 1A–C).
mandible area. We performed MRI of the mandible area and found contrast-enhancing lesions suggestive of breast cancer metastasis to the mandible bone (Fig. 1D, E). 1.3. Patients 3 An 18-year-old man with acute myeloid leukemia presented with a 3-month history of numbness and paresthesia of the left lower lip and chin. On evaluation, there were no abnormalities in the mandible area on skull base CT, enhancement brain MRI and panoramic radiography of the jaw. MRI of mandible area revealed a contrast-enhancing lesion of the left mandible bone suggestive of leukemic infiltration (Fig. 1F). 2. Discussion In patients with NCS, affected localized areas that could result in isolated chin or lower lip sensory changes are very limited, and most affecting lesions found on the inferior alveolar or mental nerves or these branches in the mandible. In addition, skull base lesions involving the pathways of the mandible branches of the trigeminal nerve such as Meckel's cave or the foramen ovale also represent candidate pathologies. In contrast, axial brain lesions including supratentorial or infratentorial parenchymal lesions are uncommonly to be associated with these isolated symptoms. Nevertheless many neurologists and oncologists perform routine enhancement brain MRI and this is arguably indicated anyway, to examine for other causes such as leptomeningeal metastasis. Thus, abnormalities are not found on imaging studies, despite comprehensive evaluation of the whole brain [3,4,6–8]. Routine brain MRI does not cover the mandible area, which is the most common location of metastatic lesions causing NCS [9]. In addition, mandibular MRI could detect contrast-enhancing soft tissue lesions that were not apparent on panoramic X-ray, CT or bone scan. Therefore, we suggest that the clinicians should include the mandible to detect metastatic lesions in patients with NCS. Since a prompt diagnosis can significantly improve treatment course and prognosis, recognizing the potential clinical significance of unilateral chin or lip numbness is critical. This report presents further examples for the importance of appropriate imaging in NCS patients and suggests that physicians should employ oromandibular MRI in addition to brain MRI. Conflict of interest The authors have no conflicts of interest to disclose. References
1.2. Patient 2 A 65-year-old woman with breast cancer presented with numbness of the left chin and lower lip. Another oncologist performed brain MRI and no corresponding lesion was found, but this MRI did not cover the
http://dx.doi.org/10.1016/j.jns.2014.07.029 0022-510X/© 2014 Elsevier B.V. All rights reserved.
[1] Laurencet FM, Anchisi S, Tullen E, Dietrich PY. Mental neuropathy: report of five cases and review of the literature. Crit Rev Oncol Hematol 2000;34:71–9. [2] Friedrich RE. Mental neuropathy (numb chin syndrome) leading to diagnosis of metastatic mediastinal cancer. Anticancer Res 2010;30:1819–21. [3] Fan Y, Luka R, Noronha A. Non-Hodgkin lymphoma presenting with numb chin syndrome. BMJ Case Rep 2011. http://dx.doi.org/10.1136/bcr.01.2011.3712.
266
Letter to the Editor
Fig. 1. (Patient 1) The scan lines of midsagittal scout view of routine brain magnetic resonance imaging (MRI) (A); it could not cover the mandible, which is the most common location of metastatic lesions causing numb chin syndrome. The scan lines of midsagittal scout view of mandibular MRI (B); contrast enhanced T1-weighted fat suppression sequence revealed an enhancing lesion (white arrow) of the right mandible (C). (Patient 2) Contrast enhanced T1-weighted fat suppression mandibular MRI showed enhancing masses (white arrows) of the bilateral mandible (D and E), which were not shown on computed tomography. (Patient 3) Contrast enhanced T1-weighted fat suppression mandibular MRI demonstrated an enhancing lesion (white arrow) of the left mandible (F). This lesion was not found on skull base computed tomography or panoramic radiography of the jaw.
[4] Seymour JF, Rodriguez MA. Mental neuropathy (numb chin syndrome): a harbinger of tumor progression or relapse. Cancer 1993;71:874–5. [5] Baskaran RK, Krishnamoorthy, Smith M. Numb chin syndrome—a reflection of systemic malignancy. World J Surg Oncol 2006;4:52. [6] Zaheer F, Hussain K, Rao J. Unusual presentation of ‘numb chin syndrome’ as the manifestation of metastatic adenocarcinoma of the lung. Int J Surg Case Rep 2013;4:1097–9. [7] Jenkins RW, McDonald K, Greenberg CS. Numb chin syndrome in acute myeloid leukemia. Am J Med Sci 2012;344:237–40. [8] Sasaki M, Yamazaki H, Aoki T, Papadhimitriou S, Paterakis G, Stiakakki E, et al. Bilateral numb chin syndrome leading to a diagnosis of Burkitt's cell acute lymphocytic leukemia: a case report and literature review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;111:e11–6. [9] Assaf AT, Jürgens TP, Benecke AW, Riecke B, Blessmann M, Zrnc TA, et al. Numb chin syndrome: a rare and often overlooked symptom. J Oral Facial Pain Headache 2014;28:80–90.
Tae-Won Kim Jeong-Wook Park Joong-Seok Kim⁎ ⁎Corresponding author at: Department of Neurology, Seoul St. Mary's Hospital, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul 137-701, Republic of Korea. Tel.: +82 2 2258 6078; fax: +82 2 599 9686. E-mail address: [email protected] (J.-S. Kim). 6 May 2014
