|Year : 2015 | Volume
| Issue : 2 | Page : 298-301
Tubular adenoid cystic carcinoma of palate: A rare case report
Deepanshu Garg1, Mysore Kantharaja Sunil2, Ashwarya Trivedi2, Deepika Kapoor3
1 Department of Oral Medicine and Radiology, College of Medical sciences, Bharatpur, India
2 Department of Oral Medicine and Radiology, Guru Nanak Dev Dental College and Research Institute, Sunam, Punjab, India
3 Department of Pedodontics and Preventive Dentistry, College of Medical sciences, Bharatpur, India
|Date of Submission||04-Jul-2014|
|Date of Acceptance||18-Oct-2015|
|Date of Web Publication||21-Nov-2015|
Chanchal Hospital, Royale Estate, Bhawanigarh, District - Sangrur, Sangrur - 148 026, Punjab
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Adenoid cystic carcinoma (ACC) is a rare malignant tumor that affects the major and minor salivary glands, the lacrimal glands, the ceruminous glands and occasionally the excretory glands of the female genital tract. 30-40% of these carcinomas occur in the head and neck region. Approximately 50-70% of the cases have been reported in the minor salivary glands. The most common location is the palate, generally in the area of the greater palatine foramen. ACC is generally characterized by a slow growth rate, and it is often present for several years before the patient seeks treatment. Here we present a case of 42-year-old female who came to the department for the complaint of a swelling over the right side of palate since 2-3 months which was diagnosed as a benign tumor initially, but was confirmed as tubular ACC histologically.
Keywords: Adenoid cystic carcinoma, cylindroma, malignant tumor, palate, salivary gland tumor
|How to cite this article:|
Garg D, Sunil MK, Trivedi A, Kapoor D. Tubular adenoid cystic carcinoma of palate: A rare case report. J Indian Acad Oral Med Radiol 2015;27:298-301
|How to cite this URL:|
Garg D, Sunil MK, Trivedi A, Kapoor D. Tubular adenoid cystic carcinoma of palate: A rare case report. J Indian Acad Oral Med Radiol [serial online] 2015 [cited 2021 Jul 29];27:298-301. Available from: https://www.jiaomr.in/text.asp?2015/27/2/298/170164
| Introduction|| |
Adenoid cystic carcinoma (ACC) is an epithelial malignant neoplasm of the salivary glands which was first described by three Frenchmen (Robin, Lorain, and Laboulbène) in their reports published in 1853 and 1854. It was they who described the cylindrical appearance of this tumor.  Approximately 31% of the lesions affect the minor salivary glands, particularly the palate, though they can also be observed in the submandibular and parotid glands. Although it presents a widespread age distribution, peak incidence occurs predominantly among women, between the fifth and sixth decades of life. Typical clinical findings include slow growth, local recurrence, perineural invasion, and distant metastasis. 
ACC is well known for its prolonged clinical course and the tendency for delayed onset of the distant metastases. The distant metastases and regional lymphatic spread may even occur as late sequela, with the patient often dying of disease, sometimes many years after the original diagnosis. The lungs are the sites of predilection for distant metastases. Metastases to bone, liver, and brain have been also reported in previous articles. Regional lymphatic spread is rather uncommon. The clinical course is often relentless and fatal if this occurs. Long-term survival can be achieved particularly with combined surgery and radiotherapy.  Three histological subtypes of ACC are known: Cribriform, tubular, and solid. They may occur either separately or together in the same tumor, and the solid subtype is the most aggressive. A unique feature of ACC is the propensity for perineural invasion, even with early-stage tumors. Tumor is graded according to Szanto et al. as cribriform or tubular (grade I), less than 30% solid (grade II), or greater than 30% solid (grade III). 
| Case Report|| |
A 42-year-old female patient visited the Department of Oral Medicine and Radiology with a chief complaint of swelling in the right palatal region since 2-3 months. History of presenting illness revealed a small swelling which gradually increased to attain the present size. Pain was mild, dull aching in nature, intermittent, radiated to neck region, aggravated on chewing food, and relieved on its own. Extraoral examination revealed no facial asymmetry [Figure 1]; a solitary right submandibular lymph node, approximately 1.5 cm in diameter, was palpable which was hard in consistency, fixed to underlying tissue, and non-tender. Examination of the lesion revealed a diffuse swelling, approximately 2 × 2 cm, present over the right posterior palate, starting from the distal aspect of 14 up to the distal aspect of 17 and from the cervical region of upper teeth up to the midpalatal raphe [Figure 2]. On palpation, the swelling was firm to hard in consistency, moderately tender, non-compressible, and no pus was seen extruding from the swelling. Based on history and clinical examination, a provisional diagnosis of benign tumor of palate was made with differential diagnoses including pleomorphic adenoma and fibrous dysplasia.
|Figure 2: Intraoral picture showing swelling over the right palatal region|
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The patient was subjected to investigations such as intraoral periapical radiograph (IOPA) with respect to 15, 16, 17 [Figure 3] which showed a diffuse area of altered trabecular pattern and increased radiolucency starting from the mesial aspect of 15 up to 1 cm distal to 17 and superoinferiorly from the crest of alveolar ridge up to 1 cm superior to the apical portion of 17 with loss of lamina dura in relation to the radicular portion of 16 and 17. Maxillary cross-sectional occlusal view [Figure 4] showed a diffuse area of increased radiolucency, approximately 1 cm in diameter, with respect to the occlusal and radicular portions of 16. Panoramic radiograph (OPG) [Figure 5] showed a diffuse area of increased radiolucency starting from the mesial aspect of 15 up to 0.5 cm distal to 17 and superoinferiorly from the crest of alveolar ridge up to 1 cm superior to the apical portion of 17 with loss of inferior wall of maxillary sinus depicting involvement of the maxillary sinus. Incisional biopsy of the swelling was taken which confirmed the lesion to be Grade-I Stage-III tubular ACC [Figure 6]. The patient was treated at PGI, Chandigarh by performing partial maxillectomy followed by postoperative radiotherapy.
|Figure 3: IOPA showing increased radiolucency starting from the mesial aspect of 15 up to 1 cm distal to 17|
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|Figure 4: Maxillary cross-sectional occlusal view showing a diffuse area of increased radiolucency approximately 1 cm in di ameter in relation to the occlusal and radicular portions of 16|
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|Figure 5: OPG showing increased radiolucency starting from the mesial aspect of 15 up to 0.5 cm distal to 17|
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| Discussion|| |
ACC accounts for 21-42% of minor salivary gland cancers and occurs most frequently on the hard palate. It is characterized by its infiltrative growth and perineural invasion. Spread to regional lymphatics is relatively uncommon, but hematogenous spread occurs in 25-50% of the cases which directly affects the prognosis. Systemic involvement is said to occur in the presence of uncontrolled disease at the primary site.  ACC is thought to arise from the mucus-secreting glands. It arises specifically from the intercalated ducts, and electron microscopy shows that it arises from cells that can differentiate into epithelial and myoepithelial cells.  These mucus-secreting tumors are confined to structures derived from the foregut (i.e. the parotid, submandibular, and sublingual glands, and the mucus glands throughout the upper respiratory tract). 
The clinical behavior of ACC is a paradox. First, the tumor growth is slow, but its clinical course is relentless and progressive, and the same behavior was shown by the lesion in this case. Second, operative intervention is usually feasible, but multiple local recurrences are the rule. Third, metastatic spread to regional lymph nodes is uncommon, but distant spread to the lungs and bones is frequent. And fourth, 5-year survival rates are optimistically high, but 10-to 20-year survival rates are dismally low. 
Histopathologically, it presents three patterns: Cribriform, tubular, and solid. The histologic variety of this case was tubular. The most common variant is the cribriform pattern, in which the epithelial cells are arranged in multiple cylindrical spaces, having a pseudocystic appearance, and many of these pseudocysts contain a hyaline material. It shows "honeycomb or Swiss cheese pattern." Stromal connective tissue becomes hyalinized and surrounds the tumor cells forming a structural pattern of cylinders from which the lesion derived the name cylindroma. The tubular type is made up of ducts that can be formed by one or two layers of cells similar to the myoepithelial cells. It is less aggressive than cribriform type. The solid variant is composed of solid epithelial islands with central areas of necrosis; the cells are small, basophilic, and hyperchromatic with a densely granulated nucleus and scarce mitotic figures. This type has the worst prognosis among all the above. 
Radiological investigations, especially computed tomographic (CT) scans, are important to delineate the tumor, to plan the extent of surgery, and to look out for recurrences as a follow-up postoperatively. Pulmonary and skeletal surveys are important to rule out distant metastasis.  A combination of surgery followed by radiotherapy is highly recommended to control the local disease and limit distant metastasis. The case discussed here also was treated by a combination of surgery and radiotherapy. 
| Conclusion|| |
Although ACC is a relatively uncommon neoplasm, it is a problematic pathology due to the high tendency toward local recurrence and development of distant metastasis; therefore, it requires close monitoring throughout the life of the patient. For this reason, early detection of the tumor is needed in order to enable early prognosis and provide a better quality of life for the patient.
Declaration of Patient Consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]