|Year : 2014 | Volume
| Issue : 1 | Page : 54-56
An unusual cause of trigeminal neuralgia
Narendra Hulikal1, Nadiminti Raghu Vamsi1, Radhika Kottu2, Bhuma Vengamma3
1 Department of Surgical Oncology, Sri Venkateswara Institute of Medical Science, Tirupati, Andhra Pradesh, India
2 Department of Pathology, Sri Venkateswara Institute of Medical Science, Tirupati, Andhra Pradesh, India
3 Department of Neurology, Sri Venkateswara Institute of Medical Science, Tirupati, Andhra Pradesh, India
|Date of Web Publication||10-Mar-2014|
Department of Surgical Oncology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Adenoid cystic carcinoma (ACC) of minor salivary glands is an uncommon malignancy. The disease is a paradox with slow, indolent growth; but high local recurrence rates. Late metastasis is a characteristic feature. We present an unusual presentation of ACC of the posterior third of tongue masquerading as trigeminal neuralgia.
Keywords: Adenoid cystic carcinoma, minor salivary gland tumors, tumors of the tongue, trigeminal neuralgia
|How to cite this article:|
Hulikal N, Vamsi NR, Kottu R, Vengamma B. An unusual cause of trigeminal neuralgia. J NTR Univ Health Sci 2014;3:54-6
| Introduction|| |
Adenoid cystic carcinoma (ACC) is an infrequent malignant lesion that originates from salivary glands. It represents approximately 1-2% of all malignant neoplasms of the head and neck, and up to 10-15% of all malignant salivary gland neoplasms.  The most common intraoral site for minor salivary gland tumors is the hard palate, followed by the base of the tongue where up to 96% of all tumors are malignant, and ACC represents 30% of them. ,
| Case Report|| |
A 50-year-old postmenopausal lady presented to us with complaints of shooting pain over the left hemi face, ear, and neck for the past 2 years, present throughout the day. There were no specific aggravating factors and it was relieved temporarily by medications. The patient also gave history of nonprogressive dysphagia for solids. The patient had been shuttling around for the past 2 years across various departments such as dental; ear, nose, and throat (ENT); and surgical gastroenterology without any relief; and was finally diagnosed to have atypical trigeminal neuralgia involving maxillary and mandibular branches. The patient was treated for a couple of months without any improvement and was referred to surgical oncology department with an interesting finding.
On examination, there was no visible abnormality in the oral cavity; but an indurated submucosal lesion of size 2 × 2 cm was palpable on the left lateral aspect of posterior one-third of tongue. There were no palpable neck nodes. Contrast enhanced computed tomography (CECT) showed a soft tissue density lesion at base of tongue left side 3 × 2 cm size extending onto the tonsillar fossa with no midline extension. We proceeded with examination under anesthesia and an incisional biopsy which was called out as ACC. The patient was taken up for definitive surgery and a wide local excision of the lesion with a margin of more than 2 cm all around was done [Figure 1]. The defect was closed primarily. Postoperative period was uneventful and the patient was relieved of the pain which was tormenting her for the past 2 years. The final histopathology report revealed a tumor of size, 2.6 × 0.8 cm, reported as ACC; grade II arising from minor salivary gland of tongue [Figure 2] and [Figure 3]. Since the tumor showed perineural infiltration and positive base, she was referred for adjuvant radiation. Patient received adjuvant radiotherapy and is free of pain 6 months from surgery, but with mild difficulty in swallowing due to surgery on the posterior tongue and xerostomia.
|Figure 3: Hematoxylin and eosin (H and E; ×10, low power view) stained section showing predominantly tubular pattern, focal cribriform pattern, and perineural infiltration|
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| Discussion|| |
The minor salivary glands are distributed throughout the mucosa of upper aerodigestive tract. The most common site of minor salivary gland tumors is palate followed by tongue. Neoplasms of the minor salivary gland occur less frequently than those arising from the major glands. ACC is an extremely unpredictable neoplasm regarding its evolution and behavior, growing slowly, and producing late metastasis. In various reported series, the frequency in which the tongue has been the site of origin ranges from 3.4 to 17.1%.  ACC tongue is commonly seen in the 5 th to 6 th decades and is more common in females.
ACC is thought to arise from the mucous secreting glands. It arises from the intercalated ducts, specifically from cells that can differentiate into epithelial and myoepithelial cells. Histologically; ACC presents three patterns, cribriform, tubular and solid; the most common variant is the cribriform pattern. The solid type has a poor prognosis and the cribriform type has a better prognosis. The clinical behavior of ACC is difficult to predict. The tumor grows slowly, in a relentless, progressive fashion. Though operative intervention is usually feasible, multiple recurrences are the rule. The metastatic spread to regional lymph nodes is uncommon, but distant spread to the lungs and bones is frequent. The 5-year survival rates are optimistically high, but 10-20-year survival rates are dismally low. The recognized prognostic factors include clinical stage (most important), histological variable, perineural invasion, anatomical localization, margin status, and the histopathology grade. ,, Diagnosis is by biopsy and CT/magnetic resonance imaging (MRI) can be used for evaluating the tumor extent. MRI with gadolinium is the preferred modality in evaluating possible perineural spread into the skull base.
Surgery is the cornerstone of treatment, may be performed in the form of partial glossectomy, hemiglossectomy, total glossectomy with or without preservation of the larynx which depends on the extent of the lesion. For cases requiring reconstruction, this can be accomplished with a flap, either pedicled myocutaneous or free microvascular flap.  In contrast to more common squamous cell cancers of the tongue, surgery for ACC is more likely to be associated with positive excision margins mainly due to presence of perineural invasion. , Following surgery, adjuvant radiotherapy is recommended in cases of advanced T stage, nodal involvement, presence of positive margins, and perineural invasion.  Delayed onset of distant metastasis is a characteristic feature which mandates prolonged follow-up. Lung is the most common site; but many sites including cerebrum, bone, liver, thyroid, spleen, and pancreas have been published. Metastasis in lung may remain dormant for many years.
The interesting fact about our case was the presence of facial pain/trigeminal neuralgia which has been so far reported in ACC originating from skull base, infratemporal fossa, intracranial-temporal region. This would be discernible due to the sites of origin and involvement of fifth cranial nerve in its pathway. There has been a case report of ACC with perineural invasion even without mass lesion hypothesized to cause the symptoms.  Perineural invasion was seen in our case and irritation of the branches of fifth cranial nerve might be the possible mechanism involved here, as the patient was relieved of her symptoms postsurgery.
To conclude, ACC of the tongue is a rare entity where early diagnosis and adequate treatment are important factors from a functional point of view, since these are indolent tumors that produce diffuse invasion. Surgery is the cornerstone of treatment and adjuvant radiotherapy plays an important role. Metastatic disease is still a difficult situation to handle due to lack of adequate therapies.
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[Figure 1], [Figure 2], [Figure 3]