INTRODUCTION

Meningiomas are one of the largest groups of brain tumors. They come in two forms:intracranial and extracranial. The extracranial location is very rare. Approximately 6%-17% of all meningiomas can be found in extracranial regions[1]. Male patients are more likely to have extracranial meningiomas[2]. We describe a rare case of primary extracranial meningioma of the maxillary sinus in a 54-year-old female patient presenting as buccal swelling and headache. Regardless of the grade, the recommended treatment is complete surgical excision if possible; we used a combined surgical approach to achieve complete excision of the lesion. The clinical, histological and immunohistochemical features are described. The possible histogenesis and the differential diagnosis are also discussed. Subsequently, we reviewed the literature on this respect.

CASE PRESENTATION

Chief complaints

A 54-year-old female patient presented with right buccal swelling for 2 years and headache for 2 mo to the Department of Head and Neck Oncology Surgery, West China College of Stomatology, Sichuan University.

History of present illness

The patient visited a local hospital and started anti-inflammatory and analgesic drugs as they considered the symptoms to be caused by cold and toothache, but the pain did not improve significantly. The patient again visited Guangyuan People’s Hospital seeking further treatment. The biopsy taken showed the spindle cell tumor in the right maxillary sinus, which was further examined by immunohistochemistry. The patient denied any shortness of breath, nausea, dysphagia, hoarseness, loss of consciousness and any neurological or constitutional symptoms at any time.

History of past illness

The patient had no previous medical history.

Personal and family history

She was a non-smoker with no specific family history.

Physical examination

On extra-oral examination the mass located in the right face was non-tender, fixed and non-pulsatile and sessile (Figure 1A). The patient did not have any palpable lymph nodes or associated neck masses. Upon intra-oral examination, an obvious buccal swelling covered with slightly red oral mucosa was present. The majority of the mass was located in the right maxillary sinus and involved the base of the maxilla.

Laboratory examinations

The patient underwent biopsy of the mass using gingival incision extending as far as the upper first molar teeth under local anesthesia. Biopsy reported a grade I primary extracranial meningioma with low mitotic activity. Hematological examinations were within normal limits.

Imaging examinations

March 31, 2021

On June 6, 2016, under general anesthesia “extended resection of right maxillary meningioma; right maxillary extended resection; inferior turbinate partial resection;middle turbinate partial resection; right-sided canal neurotomy; right trigeminal peripheral branch transection; A1 extraction; A1-A7 gingival flap; and free skin patch repair” was performed.

Computed tomography (CT) demonstrated the presence of a large, well-defined soft tissue mass measuring about 7 cm × 6 cm × 6 cm occupying the entirety of the right maxillary sinus, affecting nearby sphenoid and ethmoid sinuses, without affecting the dura mater or endocrinal structures. The surrounding structures were compressed by the mass, and the mass extended from the roof of the oral cavity into the skull base. CT on bone window setting showed an expansive mass with a high density area in the right maxillary sinus. The anterior and lateral walls of the maxillary sinus were thinned and destructed by the expanding mass, with erosion of the wall of the right maxillary sinus as well as orbital floor. (Figure 1D and E). Imaging study based on comprehensive detection of the lesion revealed that there was no evidence of intracranial extension and metastatic nests.

FINAL DIAGNOSIS

Grade D (Fair): 0

TREATMENT

As intracranial invasive meningioma was excluded, the surgery was decided to be performed by the Oral and Maxillofacial Surgeons. Total maxillectomy together with the excision of the tumor and the adjacent paranasal structures, following reconstruction of the orbit and maxilla with tissue patch was performed.

2）引入第三方评价机构。为提高中医类专业实践教学评价效能，避免高校在实践教学评价体系中既是运动员又是裁判员的尴尬，结合当前教育评价环境，综合来看，引入社会第三方教育评价机构是目前更加科学合理的评价机制。由高校制定好相关评价标准和制度，第三方教育评价机构负责组织实施，双方各司其职，共同促进教学评价工作朝健康、良性的方向持续发展[3]。

（三）缺乏责任感。做作业没有明确的意识，不能正确的解读文本材料。对作业练习等应付了事。不重视考试，缺乏竞争意识。抱着我反正不会做，可有可无的态度参加考试，考后更不注意总结反思。久而久之，造成误差积累，使学习更加困难，丧失学习信心。

Frozen pathology showed spindle cell tumor with extensive necrosis in the right maxilla, which was confirmed by extensive biopsy and immunohistochemical staining.The operation lasted for 2 h and 5 min. The blood loss was 650 mL, and the fluid infused was 2600 mL during the operation. After the operation, the patient returned to the intensive care unit. The vital signs of the patient were observed. Ceftriaxone 2.0g IV BD for 4 d was used to treat infection and prevent intracranial infection.Postoperative nutritional support and antitumor therapy were used.

Meningiomas can exist as intracranial or extracranial brain tumors and are benign,slow-growing tumors. The extracranial location accounts for 2% of all these tumors[3]and found most often in male patients and in young individuals[4]. Due to their unusual symptoms and lack of prevalence, primary extracranial meningiomas are often misdiagnosed[5]. Fortunately, 80% of extracranial tumors are benign[6]. Cases of extracranial meningioma of the sinonasal tract[7], retromolar area[8], eyebrows[9],pelvis[10],have also been reported. Some of the published reports of extracranial meningiomas are listed in Table 1. Histologically, primary extracranial meningiomas do not differ from intracranial, and most of these tumors are sporadic with unclearetiology[11]. Primary extracranial meningiomas have been considered as arising independently from cranial nerve sheaths or from extracranial embryonic rests of arachnoid cells and as extracranial metastases of a primary intracranial meningioma,but their origin has not been completely established[12].

Immunohistochemically, the tumor cells were strongly positive for vimentin(Figure 3A), focally positive for epithelial membrane antigen (Figure 3B) and CD99(Figure 3C). The cells showed negative staining for signal transducer and activator of transcription 6 (Figure 3D) and CD34 (Figure 3E). The MIB-1 (Ki-67) labeling index was 15% (Figure 3F),focally positive.

OUTCOME AND FOLLOW-UP

The patient was discharged with the following advice: perform mouth opening exercises; fabricate lumbar appendage in Prosthodontic Department a month later;radiotherapy should be done; proper nutritional support, proper oral hygiene and proper wound care; avoid spicy, acidic and irritating foods; and review after discharge for 1 mo and follow-up for discomfort.

扬中市位于镇江市东部江心，黄金水道——长江中下游，苏南现代化建设示范区内，是由太平洲、中心沙、雷公岛、西沙岛组成的城市。其东北与泰州、扬州隔江相望，西南与镇江、常州一衣带水，南桥与沪宁高速公路和京沪铁路相接，北渡可联京沪高速公路。其距上海浦东国际机场与南京禄口国际机场分别为2.5小时和1.5小时车程。

对两种不同频率激励下的柴油油样分别进行3次试验求其平均值，然后对比采用标准方法的检测值，求取两者的差值。柴油凝点检测结果见表2。

DISCUSSION

The entire tumor specimen was submitted for histology, and fresh tissue was fixed in formaldehyde solution for ultrastructural analysis. Histologically, the specimen consisted of epithelioid lobulated tissue, separated by abundant collagen fibers(Figure 2A and B). Image analysis at high magnification showed a thick fibrous capsule and was composed of interwoven fascicles of spindle-shaped meningiocytes and collagen fibers that were arranged into lobules. The tumor cells had abundant cytoplasm and indistinct cytoplasmic borders, arranged in whorled and lobulated patterns. There was osteoid formation in the tumor. No cytologic atypia or necrosis were discovered, but some mitoses were present. The specimen showed abundant cytoplasm and indistinct cytoplasmic borders, arranged in whorled and lobulated patterns (Figure 2C and D). Based on the hematoxylin and eosin sections, the lesion was diagnosed as a fibrous meningioma.

The present case shows the clinical and imaging aspects of extracranial meningioma of the maxillary sinus in an elderly lady. Primary extracranial meningioma of the paranasal sinuses is rare[13]. In general, the most common signs and symptoms of paranasal sinus meningiomas may mimic cases of sinusitis with nasal obstruction,anosmia, facial pressure or pain, epistaxis and rhinorrhea[14,15]. Meningiomas in the extracranial space often present with nonspecific symptoms until the tumor has reached a significant size. This was the case with our patient who had buccal swelling for 2 years, which has been neglected by the patient until the headache started. Clinical examination should be comprehensive because more than 10% of cases may remain asymptomatic even in advanced stages[15]. Imaging studies, especially CT and magnetic resonance imaging scans, have proved to be useful in the diagnosis and management of meningiomas. The differential diagnosis should include a variety of benign and malignant neoplasms such as melanoma, olfactory neuroblastoma,carcinoma, hemangioma, sarcoma and aggressive psammomatoid ossifying fibroma[10,14]. Histology is therefore essential, and the general histologic features and immunohistochemically findings can usually differentiate between these tumors, as extracranial meningioma presents with solid nests of meningothelial cells arranged in sheets or whorls with a fibroadipose background[5,13]. Immunohistochemistry is helpful in confirming the diagnosis; extracranial meningiomas tend to show strong positivity towards vimentin and epithelial membrane antigen, as indeed occurred in our patient, and are focally positive for CD99 and Ki-67.

Both CT and magnetic resonance imaging are essential in preoperative surgical planning. Surgery is the only curative treatment, and surgical excision of the mass should be performed if possible. External beam radiation therapy has been shown to be effective and therefore reserved as a palliative approach[16,17]. In the present study, surgical therapy was determined to be the optimal treatment approach for several reasons. The various treatment previously performed on the current patient did not result in an evident recession of the mass. Without surgical intervention, a firm mass and unbearable headache would remain.

CONCLUSION

The present study reports successful surgical treatment of a patient with a rare primary extracranial meningioma in the maxillary sinus. The present study demonstrated that imaging studies can aid in the diagnosis and biopsy and is useful to specify diagnosis. Surgical treatment is a viable option for the successful management of extracranial meningiomas in the maxillary sinus, and complete postoperative care often requires a multidisciplinary approach.

目前，世界各国都深刻意识到低碳经济是全人类发展的必然趋势。对于因二氧化碳等温室气体过量排放所导致的气候变化和能源短缺等一系列问题，都应靠发展低碳经济作为改善措施。众所周知，电力行业作为温室气体的主要排放行业，在我国低碳经济的大环境下，扮演着至关重要的角色。如何切实有效地提升电力企业会计核算制度，从根本上降低我国的碳排量，是目前每一个电力会计工作者都应思考的问题。

The authors thank Dr. Aladimi MT from the West China school of Stomatology,Sichuan University (Chengdu, China) for his kind help in the manuscript preparation and for certain important suggestions for the present manuscript.

李叔和听到这个消息，有点心惊肉跳。捻船的时候，李老鬼对他说，我早就知道，这个娘们属是非窝子，我不让你给她有来往，是看她面相上有杀气哩，还好，你早给她断了，这事儿粘不到咱身上。