Adenoid cystic carcinoma (ACC) was first described by Robin, Lorian and Laboulbene in their articles published in 1853 and 1854, in which the cylindrical appearance of the tumor was discussed. Billroth in 1859 has identified the tumor as cylindroma and has also reported great recurrent tendency of this tumour. Spies in 1930 gave the name “adenoid cystic carcinoma” in his discussion of cutaneous and non-cutaneous tumors of the basal cell type.[1]
ACC is an uncommon epithelial tumor of the salivary glands. It accounts for about 5% to 10% of all salivary gland neoplasms with 2% to 4% of malignant occurrences of the head and neck region. Approximately 31% of lesions are seen in minor salivary glands, especially the palate, but they may also be seen in the submandibular and parotid glands. [2]
ACC has a widespread age distribution but is observed predominantly in women, between the 5th and 6th decades of life.[3] Typical clinical findings contain local recurrence, slow growth, perineural invasion and distant metastasis. [4]
We present adenoid cystic carcinoma of the base of tongue, and a brief literature review on the report.
CASE REPORT
A 65-year-old female patient had complained of a swelling in the median part of the tongue and pain in tongue since 10 months, which had started spontaneously and then showed increase in size. She had difficulty with speech and swallowing. The patient reported an insignificant past medical and family history except she had hypertension as systemic disease. Extra-oral examination and palpation revealed cervical lymph node chain with normal size. On intraoral clinical exam, a firm sessile nodule of about 2×1 cm in diameter with a similar coloration to that of the buccal mucosa was observed (Figure 1). There was pain in palpation. Based on patient´s history and clinical exams, associated with suspicious appearence of observed lesion with irregular form, malignant neoplasm was thought as early diagnosis.
Magnetic resonance imaging (MRI) revealed a ill-defined, hypointense lesion on T1 and T2 weighted images (Figure 2a,b). The lesion enhanced markedly on post-contrast T1 with fat suppression (Figure 3a,b). Lesion was seen in left lateral and posterior aspect of the base of tongue extending upto lingual septum and crossing the midline. The lesion was involved the genioglossus and intrinsic muscles of the tongue base and infiltrated to posterior of left sublingual space. There was indistinct border between the lesion and left lingual tonsil. It was not seen lymph nodes which pathological size were not observed. There was oval shaped lymph node measured 10×5 mm in the cervical level 2b. (Figure 4)
Due to hypointense lesion on T2, Squamous cell carcinoma was eliminated and we thought ACC and tongue of lymphoma as differential diagnosis.
Soon after, the patient was referred to surgery and the biopsy was performed and specimen was sent for histopathologic study. Macroscopically, grayish white the tissue piece measured 1.3 × 0.9 × 0.5 cm was observed. The immunohistochemical results revealed EMA and PanCK in positive in tumour cells. However, there was perineural infiltration on serial sections.
Based on the clinical, MRI and histopathological findings, a final diagnosis was made as adenoid cystic carcinoma of tongue base.
DISCUSSION
Neoplasms of accessory salivary gland origin occur less commonly than major salivary glands. Tongue is a slightly uncommon region for salivary gland neoplasms. [5]
ACC derives from both the minor and the major salivary glands. It is an uncommon lesion and constitutes about 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 comprises 30% of them. [6] Similarly, in the study of Moran et al. [7], the hard palate is the most common site of origin, with the neoplasm arising in that site in 9 of 38 cases of ACC.
Evesson and Cawson [8] found a discreet predominance of ACC cases in women (F:M 1.2:1) with ages varying from 24 to 78 years. Similarly, our patient was female and 65 years old.
In the clinical examination, ACC of the tongue is painless, slow submucosal growth which blocks the early diagnosis of ACC. Previous studies reported that the elapse time from the first clinical appearance to the entity of symptoms ranges from 2.5 to 7 years, [9] with one case reported by Luna Ortiz et al. that had a duration of 10 months. [10] Similarly, in our case, the patient had pain and swelling within the duration of 10 month.
Table 1 shows case series of adenoid cystic carcinoma in tongue. In the study of Spiro et al. [11] lesions involving accessory glands were observed in 171 patients of 242 salivary gland ACC cases while the palate was observed as the affected site in 64 patients (26%) and the tongue was reported as the second most affected area. Isacsson and Shear [12] reported neoplasm occurrences in the palate, floor of the mouth, tongue and gingiva, respectively. Khan et al. [13] reported that ACC originates from major salivary glands in 26 of 68 cases and from minor salivary glands in rest of them, and 5 ACC cases in tongue of 68 cases.
MRI has higher accuracy in describing the soft tissue lesion. [14] For this reason, in our case, MRI was used as imaging modality.
Histologically, ACC has three different types as cribriform, tubular and solid. Worst prognosis was based on the presence of increased mitotic figures. It also has a strong neurotrophism including the nerves neighboring on the lesion. [15] Soares et al. [15] and Batsakis et al.[16] reported that survival rate was less in the solid pattern than the cribriform and tubular patterns in their studies about the relationship between the histological pattern and the prognosis.
Surgical excision of the tumor with adjuvant radiotherapy in patients with advanced T stage and/or positive surgical margins is the treatment choice. [17] The deficiency of survival advantage for patients treated with combination surgery and radiotherapy is presumed to be because of the high rate of distant metastases and the relatively high possibility of long-term survival after salvage therapy for patients who experienced locoregional recurrence. [18] Nascimento et al. [19] reported that local recurrence was identified in 17 (37%) of the 46 patients.
Patients who have ACC in the tongue complain insufficient function. Thereby, improvement the speech and swallowing of the patient must be the purpose of the treatment. As a result, the quality of life for the patient will increase.