A polymorphous low-grade adenocarcinoma (PLGA) is the second most common malignancy of the minor salivary glands (after a mucoepidermoid carcinoma); the hard palate is the most frequently involved head-and-neck site ¹. PLGAs affect patients of all ages, from 16 to 94 years reported, with a mean age of 59 years, and exhibit a female predilection. The typical presentation is an indolent submucosal mass, which may occasionally be painful or even ulcerated ². The most common site of a PLGA is the palate, followed by the buccal mucosa, the upper lip, the retromolar triangle, and the tongue ³¹. We present a (rare) case of tongue PLGA in which total surgical excision was performed.

A 41-year-old male presented to our otolaryngological department with a mass at the left side of the tongue. He complained of no symptom other than the mass. On rigid laryngoscopy, a tumour 1 cm in diameter with an intact overlying mucosa was evident at the left side of the tongue near the papilla circumvallatta (Figure 1). Neither neck palpation nor ultrasonic neck evaluation revealed any cervical lymphadenopathy. Computed tomography of the head-and-neck was performed after administration of intravenous contrast, and revealed that the tongue mass was both superficial and small. The patient underwent surgical excision under general anaesthesia both as treatment and to allow pathological diagnosis. The mass was hard and the overlying mucosa was clearly distinguishable from the surrounding normal mucosa. After resection, we performed primary wound closure. The pathological diagnosis was a PLGA and the resection margins were negative.

Figure 1: A tumor 1 cm ın sıze with intact overlying mucosa, was found at the left side of the tongue near the papilla sırcumvallatta (as shown by black arrow).

The lesion was encapsulated; the cells formed tubular, cribriform, and trabecular patterns (Figure 2).

Figure 2: A and B. Polymorphous low grade adenocarcinoma: the invasive tumor was near the mucous salivary glands (∗) and Tumour cells arranged in tubuler, cribriform, solid, trabecular pattern.

The patient did not complain of postoperative dyspagia or pulmonary aspiration. He has received close follow-up, and no recurrence has been observed during the first postoperative year.

A PLGA is a low-grade malignancy, first described by Evans and Batsakis ⁴¹ as a malignant tumour arising in the minor salivary glands; the condition was previously considered to be a lobular carcinoma or a terminal duct carcinoma. PLGA constitutes around 19–26% of the malignant tumours of the minor salivary glands ⁵, developing most commonly in the hard palate, principally at the base of the tongue ⁶. We here describe a PLGA in a rare location.

Histopathologically, a PLGA is characterised by cytologically uniform, anonymous round cells arranged in several architectural patterns (hence the polymorphous descriptor). The cell growth patterns include solid, trabecular, tubular, cribriform, microcystic, and papillary presentations. In the present case, tubular, trabecular, and cribriform growth patterns were evident among cells of the periphery.

Regional and distant metastases develop in 5–15% ⁷ and 0.6–7.5% ⁸ of patients, respectively. Therefore, elective neck dissection is not recommended when treating early T- stage tumours ⁹. The prognosis is relatively good and wide surgical resection is the recommended primary treatment. Any role for radiotherapy remains controversial. However, postoperative radiotherapy may be considered if the surgical margins are positive ⁸. We found no perioperative cervical lymphadenopathy; we thus considered that the condition was benign and did not perform neck dissection. We did not schedule radiotherapy because the surgical margins were negative upon postoperative histopathological examination.

Long-term follow-up is essential to prevent transformation of the condition into a high-grade malignancy, and to detect recurrence ¹⁰. We have followed-up the patient closely; there has been no recurrence to date, 1 year postoperatively.