Numb chin syndrome revealing a mandibular metastasis: Case report

Abstract

Introduction and importance

Numb chin syndrome (NCS), although rare, is an important clinical finding. It may be a metastatic neurologic manifestation of malignancy, often with no clinically visible pathologic finding.

Case presentation

A 40-year-old female, with prior history of breast cancer, presented to our service with complaint of pain and left mandibular hypoesthesia for four months. Panoramic showed several irregular osteolytic lesions of the mandibular body. CT-scan images showed a large irregular hypodense lesion and a tissue infiltration of the left mandibular body blowing the buccal cortex. Histopathology showed a neoplastic proliferation of carcinomatous cells positive for the cytokeratin AE1/AE3. A diagnosis of breast carcinoma mandibular metastasis was made. The patient was referred sent to the oncology committee. She was treated with Palbociclib and hormone therapy.

Clinical discussion

In the oral cavity, the mandible is the most common site for metastasis. Metastatic tumors of the oral cavity may be asymptomatic or present different non-pathognomonic. Numb chin syndrome which is considered as an important presentation of oral metastases. The consideration of malignancy as a differential diagnosis may help in early diagnosis and intervention that may affect disease prognosis.

Conclusion

Dentists and other oral health care providers must be aware of this condition to consider metastatic cancer in patients with unexplained facial hypoesthesia.

Highlights

• •Mandible is the most common site for metastasis.
• •Metastatic tumors of the oral cavity may be asymptomatic or present different non-pathognomonic.
• •Numb chin syndrome is an important presentation of oral metastases.
• •Early detection of oral lesions could improve treatment outcome and survival.

1. Introduction and importance

Metastatic tumors to the oral cavity are uncommon and are generally detected at a late stage of the disease [1]. They are usually found in the jaws and less frequently in the surrounding soft tissues and salivary glands [1]^, [2]. Not only is it a sign of systemic spread of tumor cells, it can negatively affect oral functioning and esthetics [3]. The diagnosis of mandibular metastasis constitutes a challenge because its clinical symptomatology is nonspecific and it is characterized by a high clinical latency causing a delay in diagnosis [4]. Also usually seen as a clinical sign referred to in the literature is the NCS, which occurs because of the involvement of the inferior alveolar branch of the mandibular nerve. The lesion may indicate the presence of a metastasis, a yet unknown cancer, or recurrence of the disease [5]^, [6].

The authors report a numb chin syndrome as a manifestation of possible breast cancer metastasis in a 40-year-old woman. This case presentation followed SCARE Guideline Checklist 2020 [7].

2. Case presentation

A 40-year-old female patient was presented to our oral surgery department with complaint of pain and paresthesia in the lower left region of jaw for four months. The patient had been diagnosed with breast cancer two-years ago at an external center. The histological type of the primary tumor was an invasive mammary carcinoma of no special type. The TNM classification was cT4bN1Mx. She had received chemotherapy, mastectomy, radiotherapy and hormonal therapy (Tamoxifen) as treatment.

Extraoral examination showed a palpable left submandibular lymph nodes firm and fixed of size 2 × 2 cm approximately and lower lip and chin hypoesthesia. Intraoral examination revealed a slight increased volume on the left side of the mandibular body close to teeth 35 and 36. The oral mucosa had a normal appearance and texture. The analysis of the panoramic radiography showed several irregular osteolytic lesions of the mandibular body (Fig. 1).

Fig. 1.

Orthopantomogram showing a several irregular osteolytic lesions of the mandibular body.

Based on the patient's medical history and paraesthesia of the lower lip and chin, the metastatic disease was highly suspected. Contrast-enhanced computed tomography (CT) of the head was performed. The images obtained in the soft tissue window revealed an inflammatory infiltrate on the left side of the mandibular body blowing the buccal cortex (Fig. 2).

Fig. 2.

Contrast-enhanced axial CT images of the head in the soft tissue window showing an inflammatory infiltrate on the left side of the mandibular body blowing the buccal cortex (red arrow). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Serial coronal CT-scan images (bone window) showed a large irregular hypodense lesion invasion the inferior alveolar nerve (IAN) with destruction of the buccal cortex and erosions of the lingual cortex (Fig. 3).

Fig. 3.

Coronal CT-scan showing a large irregular hypodense lesion invasion the inferior alveolar nerve (IAN) with destruction of the buccal cortex and lingual cortical erosions (blue arrow). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Given the picture described, an incisional biopsy of the site was performed. The histological study found a neoplastic proliferation of carcinomatous cells made of tubular trabeculae and structures, lined by atypical cells. The stroma was fibrous (HE ×10) (Fig. 4). Immunohistochemistry showed a positivity of the tumor cells for the cytokeratin AE1/AE3 (Fig. 5). The final diagnosis was a breast carcinoma mandibular metastasis of no special type.

Fig. 4.

Photomicrograph showing a carcinomatous tumoral proliferation made of tubes and trabeculae lined by atypical cells, and developing in a fibrous stroma (HE ×10).

Fig. 5.

Automated immunohistochemistry (Autostainer:): tumor cells were diffusely positive for keratin AE1/AE3 (×20).

The patient was referred to the oncology committee for breast cancer, where she underwent bone scintigraphy and spinal magnetic resonance imaging (MRI), which showed secondary spinal tumors. Liver metastasis was detected on the abdominal, pelvic, and thoracic computed tomography scan (CT-scan), confirmed later by ultrasound. Liver function tests were also impaired.

Zoledronic acid, Palbociclib, and hormone therapy were indicated. The patient was followed up monthly. As of yet, she has received 4 cures from the palliative treatment. Pain relieved by level 3 analgesics; no jaundice or visceral crisis.

3. Discussion

Cancer is a complex disease in which cells develop aberrant proliferation and survival. The progression of metastasis severely increases morbidity and eventually mortality [8]. Oral cavity metastases account for only 1 % of all oral malignancies; these metastases to the oral cavity are commonly from the lung, kidney, liver, and prostate for men and breast, female genital organs, kidney, and colorectum for women [3]. In the oral cavity, the mandible is the most common site for metastasis, with the areas distal to the canine (including the ramus and the body of the mandible) being the most commonly involved [1].

The pathogenesis of mandibular metastasis is not completely understood; however, it is supposed to be hematogenous connected with Batson venous plexus and the presence of abrupt vessel angulation, especially in the molar and premolar regions, leading to bloodstream slowing and favoring the deposit of malignant cells [1]^, [9].

Breast cancer (BC) is the most frequently diagnosed cancer in women worldwide with more than 2 million new cases in 2020 and is also the leading cause of cancer death in women worldwide [10]. The mortality of this pathology is essentially linked to metastases (up to 90 % of case). Breast carcinoma has a great tendency to be spread by metastasis, thus it is a common clinical problem associated with bone destruction and a poorer prognosis. Breast carcinoma metastasizes to the mandibles three times as often as any other malignant tumor [8]. Clinically, metastatic tumors of the oral cavity may be asymptomatic or present different non-pathognomonic symptoms mimicking odontogenic infections such as pain, swelling, altered sensation, halitosis, gum irritation, tooth loosening and mobility, exophytic masses of soft tissues, ulceration, regional lymphadenopathy, trismus, and rarely pathologic fractures. In the present case, the only symptom was paresthesia of the left lower lip and chin, also called numb chin syndrome which is considered as an important presentation of oral metastases [1]^, [3]^, [11].

The radiological aspect of mandibular metastasis is also nonspecific and it varies according to the nature of the primary tumor. Usually, metastatic lesions present as osteolytic areas, poorly-defined with a “moth-eaten” appearance [9] and are most often secondary to breast cancer [4]. However, metastases from sites such as prostate present as a radiopaque or mixed radiopaque-radiolucent lesion [6]. In approximately 5 % of cases, the radiograph does not show any pathological image [12]. This variety of imaging features makes their diagnosis challenging, especially in the initial stages of the disease [4]^, [6]. Confirmation of the diagnosis requires histopathological examination of the presumed metastatic lesion which must be identical to that of the primary tumor [12]. A clinical and radiological extension assessment is necessary in order to evaluate the loco-regional extension of metastasis and to direct it towards the site of the primary cancer.

Since breast carcinoma will be at an advanced stage when there are oral metastases, the primary management is palliative therapy. Early detection of oral lesions could improve treatment outcome and survival [13].

4. Conclusion

This clinical situation illustrates the importance of good medical history review prior to all procedures by the medical professions dealing with oncology patients. Mandibular metastasis should not be overlooked in these patients. An awareness of this condition is crucial, especially in cases with symptoms of unexplained facial pain and numbness.

Patient consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethical approval

N/A. Ethical approval is exempt at our institution.

Funding

None.

Author contribution

Fouzia Hakkou and Hajar Ouaabbou are co-first authors, they contributed equally to this work: Diagnostic workup, Drafting the manuscript and Literature research.

Saliha Chbicheb: Supervision and critical revision.

Hafsa El Ouazzani and Nadia Cherradi: histological examination.

All authors read and approved the final manuscript.

Guarantor

Fouzia Hakkou and Hajar Ouaabbou.

Research registration number

N/A.

Declaration of competing interest

N/A.