Acinic Cell Carcinoma of the Nasal Lateral Wall

Primary acinic cell carcinoma arising in the nose is exceptionally rare. In this report, we present a unique case of an acinic cell carcinoma of the nasal lateral wall, and it is only the second such case to be reported. We also engage in a systematic review of all 18 cases of acinic cell carcinoma of the nose reported in the literature in English so far.


Introduction
Acinic cell carcinoma is an uncommon salivary tumor, which arises most frequently in the parotid gland and rarely in the minor salivary glands [1]. Most of the acinic cell carcinomas originating in minor salivary glands have been found in the oral cavity [1]. Primary acinic cell carcinoma arising in the nose is exceptionally rare, and it is thought to account for only 1-4% of all malignant nasal neoplasms [2]. Only 18 cases of acinic cell carcinoma arising in the nasal cavity have been previously reported in the literature in English [3].

Case Presentation
A 62-year-old male patient presented to our emergency room with a history of right nasal mass for 10 years. The patient reported occasionally experiencing epistaxis and in the last six months, there had been a slow, gradual growth. However, it had not been noticed during that period.
He had a round, soft, well-defined mass on the lateral nasal wall (Figure 1). An ultrasound revealed a solid oval lesion with some internal vascularization in the right wing of the nose, measuring 15 x 11 x 19 mm, which apparently caused an interruption of the cortical bone. For additional characterization of the lesion, a CT scan was performed. The CT scan showed a homogeneous nodular structure of soft tissue, centered on the region of the frontal maxillary apophysis on the right, with its erosion, and extending into the nasal vestibule. The structure measured approximately 17-18 mm in diameter; it had smooth, regular contours, and the adjacent bone limit was molded, constituting characteristics suggestive of benignity (Figures 2, 3). The surgical removal of the mass was performed. The macroscopic findings during the procedure suggested that the primary site of the mass was the right lateral wall, with expansion to the vestibule and without invasion of the nasal septum. The mass was totally excised along with the area of the surrounding skin. The postoperative period was uneventful and the patient was discharged on the same day.
Microscopically, the tumor had the appearance of classic acinic cell carcinoma. Necrosis and mitosis were absent. The neoplasm was intersected by the margins (fulguration). Given the unexpected histological diagnosis, a staging CT was performed, which showed a total excision of the lesion and no signs of local recurrence or metastasis. It was decided that the patient should undergo radiotherapy by the oncology department. At the follow-up six months later, the patient had no signs of recurrence ( Figure 4).  The mean age of the patients was 57.2 years (range: 42-76 years). Women constituted the majority of the patients (63%). Nine cases developed on turbinate, five were located on the nasal septum, two on the nasal cavity and nasal lateral wall, and only one case was reported on the vestibule. The most common presenting complaint was nasal obstruction (84%), followed by epistaxis (42%) and hyposmia (10.5%). There were no tumor markers or imaging characteristics that allowed for a preoperative diagnosis, and all cases were diagnosed after surgical excision. The diagnoses were based entirely on histopathological evaluations [3].

Author/references
Acinic cell carcinomas should be treated by complete surgical excision and the prognosis is related to tumor extension and the quality of resection [3,5,17]. Postoperative radiation is not routinely advocated for these low-grade salivary malignancies but may be used for tumors with positive surgical excision margins, tumors with extensive perineural and/or lymphovascular invasion, advanced or high-grade tumors, or recurrent tumors [18]. Chemotherapy for acinic cell carcinoma is considered ineffective [3]. Elective neck dissection is not warranted, because the incidence of cervical nodal metastasis is relatively low, with the reported nodal metastasis rates for parotid acinic cell carcinomas being 5-10% [2,17,18].
The treatment in all cases was surgery, and in five cases, patients underwent radiotherapy as well. To date, recurrence has been reported in only one case.

Conclusions
Acinic carcinoma is rarely located in the nasal cavity. Its nasal lateral wall origin is highly unusual. Curative treatment is surgery alone or surgery associated with radiotherapy. Patients with acinic cell carcinoma should be followed up for long periods, because recurrence may occur many years after the treatment. However, further studies with longer follow-up periods are needed to gain deeper insight into the clinical behavior of nasal acinic cell carcinoma.

Additional Information Disclosures
Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.