Numb chin syndrome is an uncommon maxillofacial manifestation involving mental neuropathic complications of mandibular bone metastasis with prostate adenocarcinoma. We report a case of a male, 68 years, with a history of bone tibia and spinal metastatic prostate cancer, undergoing bilateral orchiectomy for hormonal blockade and chemotherapy; disease progression was confirmed by bone scintigraphy which noted no critical points but an increase in alkaline phosphatase; therapy with abiraterone and zoledronic acid quarterly was introduced 1 year after diagnosis. The patient attended a dental appointment after 10 months of bisphosphonate use, complaining of a “tingling” sensation in the right chin mental region, 6 months after tooth extraction, with diagnostic hypothesis of medication-related jaw osteonecrosis. Intra-oral exam showed edema in the right mandibular body region extending to the painless, hardened chin, with exudate drainage as compression. An incisional biopsy was performed and anatomopathological and immunohistochemical analysis showed positive staining for cytokines and NKX3, confirming the diagnosis of adenocarcinoma metastasis. The patient was referred to continue treatment with radiotherapy and, subsequently, Xofigo and zoledronic acid to improve symptomatology and control of the adenocarcinoma. Facial numbness should alert clinicians to the potential of metastatic disease in any patient who presents with chin or jaw numbness and has no other obvious cause for their complaint, and early differential diagnosis between jaw osteonecrosis and bone metastasis in the jaw is important for immediate management and improvement in treatment and quality of life.
Prostate carcinoma (PCa) is the most common form of cancer that affects men and adenocarcinoma corresponds to 95% of malignancies  Approximately 7.5% of prostate cancer shows no symptoms, meaning men do not seek medical support [2, 3], resulting in an advanced-stage of disease, with multiple metastases . Approximately 1% of oral cancers are metastases and can be found on soft tissue or jaw bones [5, 6]. One of the signs of oral metastasis can be numb chin syndrome (NCS) due to the involvement of the inferior alveolar of the mandible nerve. [4, 5, 7, 8] NCS describes a sensory neuropathy characterized by numbness (hypoesthesia, paresthesia, dysesthesia, anesthesia) in the distribution of the terminal branch of the mandibular division of the trigeminal nerve and may be caused by nerve damage occurring during dental and maxillofacial therapies, including mandibular block  (Fig. 1). It has different terms which have been referred to in the literature. The systematic review had used the term mental nerve neuropathy (MNN) which is a neurological manifestation of cancer, characterized by numbness in the region innervated by the mental nerve: skin of the chin, oral mucosa, and lower lip of the affected hemisphere, too . Since PCa can be silent, it is important for healthcare professionals to be aware that paresthesia or any level of pain or sensory discomfort around the chin, lower lip, or gingiva mucosa could be indicative of a malignant process occurring in the patient’s body [4, 7].
The purpose of the present article was to report a case of a patient diagnosed with metastatic prostate neoplasia in the mandible; describing the approach taken, facial numbness should alert clinicians to the potential of metastatic disease in any patient who presents with chin or jaw numbness and has no other obvious cause for their complaint and a differential diagnosis between osteonecrosis of the jaw and management to improve quality of life.
After approval by the National Bioethics Committee and the patient signed the consent form for data use, we report a 68-year-old male patient with a history of bone tibia and spinal metastatic prostate cancer, undergoing bilateral orchiectomy for hormone block and chemotherapy, with disease progression confirmed by bone scintigraphy, bone marrow biopsy compatible with prostate adenocarcinoma, and no critical points according to magnetic resonance imaging, which noted an increase in alkaline phosphatase; therapy with abiraterone (1 g day) and zoledronic acid (4 mg/5 ml) quarterly was introduced. The patient attended a dental appointment referred by the clinical oncologist, complaining of a “tingling” sensation in the right chin region after tooth extraction, 41, 42, 31, and 32, in an external service approximately 6 months previously, with a presumptive diagnostic hypothesis of medication-related osteonecrosis of the jaw (MRONJ). Intra-oral vision revealed inferior toothless patient and only the presence of a tooth in the right jaw in addition to edema in the region of the right mandibular body extending to the painless, hardened chin, with exudate drainage as compression. Extra-oral examination revealed facial asymmetry, edema extending from the jaw to submandibular region; the right submandibular lymph nodes were palpable and painless (Figs. 2 and 3). The panoramic radiographic examination identified a radiopaque area of volumetric enlargement in the mandible body, and a radiolucent circumscribed image of approximately 2 cm, with radiopaque halo, in the anterior region of the right mandible, with a diagnostic hypothesis of cystic lesion in the jaw (Fig. 4). An incisional biopsy in the right jaw cystic lesion area was sent for anatomopathological analysis; histological sections stained with hematoxylin-eosin (H.E.) demonstrated segments of dense hyaline fibrous connective tissue through the proliferative/infiltrative process of small cells with irregular hyperchromatic nuclei and small, indistinct cytoplasm. These cells are arranged in the middle of the said tissue to form small amorphous infiltrates, as well as cellular cables and outlines of acinar glanduliform structures (Figs. 5 and 6; Table 1). Small pieces of material observed in one of the fragments suggested bone particles. Crushing artifacts resulting from distortions of the examined tissue limited and impaired evaluation of patient who was referred to the oncology medical team to continue treatment with radiotherapy with beam intensity modulation (IMRT) in right fields, dose of 800 cGy, in a single fraction due to secondary bone involvement and subsequent continuation of therapies with Xofigo and zoledronic acid to improve symptomatology and control disease.
Oral metastases are not common and represent 1% of oral malignancies [4,5,6,7]. The primary sites can vary, and prostate cancer is one of the most common, representing approximately 12% of cases [4, 5]. PCa bone metastases, such as lower back vertebras or pelvis, are not unusual [7, 9]. Our case had a history of metastatic lesions in L1 vertebrae and tibial bone and mandible. Hirshberg et al. analyzed 673 cases of metastatic lesions to the oral cavity and found a 2:1 predominance to the jawbone compared to soft tissues and also stated that this lesion is difficult to recognize for access reasons. For cellular and molecular factors, PCa seems to prefer jawbone and skeletal bones, with large red marrow components, as a metastatic target [6, 7].
The symptoms associated with metastatic lesions are pain, swelling, tooth mobility (when involved), halitosis, and NCS [4,5,6,7,8]. The symptoms associated with NCS follow the path of the mental nerve, a terminal branch of the inferior alveolar nerve . A tingling in the chin area is often described—which was the main complaint of our patient. However, as he reported the symptoms after extraction of inferior teeth, the first hypothesis was osteonecrosis due to the use of bisphosphonate, also common in cancer patients after chemotherapy. On intra-oral clinical examination, swelling and edema were noted in the right mandibular body region, extending to the painless, hardened chin, with exudate drainage as compression. A clinical examination is not sufficient to locate a lesion; therefore, the appearance of a mental neuropathy obliges a complete radiographic examination of the trigeminal nerve and the pain is an infrequent symptom in NCS .
Several authors report that NCS can be an important neurological indication of malignancy, and Galán-Gil (2008) had etiology relationship of the 136 cases analyzed; the most frequent primary malignant disease was breast cancer in 40.4% of cases, followed by lymphomas in 20.5%, prostate cancer in 6.6%, and leukemia in 5.1%. Table 2 shows possible diagnoses that should be considered when signs and symptoms compatible with NCS are related by a patient. Other than cancer manifestation, patients with MRONJ due to osteoporosis or cancer can present the syndrome, followed by trigeminal neuropathy, benign tumor, and other odontogenic causes, such as trauma after an extraction .
We conclude with this case report that facial numbness should alert clinicians to the potential of metastatic disease in any patient who presents with chin or jaw numbness and has no other obvious cause for their complaint and early differential diagnosis between jaw osteonecrosis and bone metastasis in the jaw is important for immediate management and improvement in treatment and quality of life.
Shen ML, Kang J, Wen YL, Ying WM, Yi J, Hua CG, et al. Metastatic tumors to the oral and maxillofacial region: a retrospective study of 19 cases in West China and review of the Chinese and English literature. J Oral Maxillofacial Surg. 2009;67:718–37. https://doi.org/10.1016/j.joms.2008.06.032.
Hirshberg A, Shnaiderman-Shapiro A, Kaplan I, Berger R. Metastatic tumors to the oral cavity - pathogenesis and analysis of 673 cases. Oral Oncol. 2008;44:743–52. https://doi.org/10.1016/j.oraloncology.2007.09.012.
Van der Waal RIF, Buter J, van der Waal I. Oral metastases: report of 24 cases. Br J Oral Maxillofac Surg. 2003;41:3–6. https://doi.org/10.1016/S0266-4356(02)00301-7.
Kim I-K, Lee DH, Cho HY, Seo JH, Park SH, Kim JM. Prostate adenocarcinoma mandibular metastasis associated with numb chin syndrome: a case report. J Korean Assoc Oral Maxillofac Surg. 2016;42:301–6. https://doi.org/10.5125/jkaoms.2016.42.5.301.
Pruckmayer M, Glaser C, Marosi C, Leitha T. Mandibular pain as the leading clinical symptom for metastatic disease: nine cases and review of the literature. Ann Oncol. 1998;9:559–64. https://doi.org/10.1023/A:1008286117771.
Lossos A, Siegal T. Numb chin syndrome in cancer patients: etiology, response to treatment, and prognostic significance. Neurology. 1992;42:1181–4.
Tejani N, Cooper A, Rezo A, Pranavan G, Yip D. Numb chin syndrome: a case series of a clinical syndrome associated with malignancy. J Med Imaging Radiat Oncol. 2014;58:700–5. https://doi.org/10.1111/1754-9485.12177.
Aerden T, Grisar K, Neven P, Hauben E, Politis C. Numb chin syndrome as a sign of mandibular metastasis: a case report. Int J Surg Case Rep. 2017;31:68–71. https://doi.org/10.1016/j.ijscr.2017.01.001.
Lu SY, Huang SH, Chen YH. Numb chin with mandibular pain or masticatory weakness as indicator for systemic malignancy. A case series study. J Formos Med Assoc. 2017;116:897–906.
Galán-Gil S, Peñarrocha-Diago M, Peñarrocha-Diago M. Malignant mental nerve neuropathy: systematic review. Med Oral Patol Oral Cir Bucal. 2008;13(10):E616–21.
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Ielo, N., Biancardi, M., Trevisan, F. et al. Jaw Metastasis from a Prostate Adenocarcinoma Associated with Numb Chin Syndrome: Case Report. SN Compr. Clin. Med. (2021). https://doi.org/10.1007/s42399-020-00720-3
- Prostate carcinoma
- Numb chin syndrome
- Osteonecrosis in jaw
- Neoplasm metastasis