Salivary gland tumors accounts for 2–6% of all head and neck neoplasms. Among all salivary gland tumors, pleomorphic adenoma is the most common tumor accounting for 60% of salivary gland tumors. Pleomorphic adenoma most commonly arises in major salivary glands which include parotid or submandibular glands. Rarely, pleomorphic adenoma arises from minor salivary glands. Among the minor salivary glands, hard palate is the most common site. Tumor in minor salivary glands are more likely to be malignant than their counterpart in major salivary glands. In contradiction to this only benign pleomorphic adenoma of minor salivary glands were found in our institute in last one year which prompted us to write this case series.

All four patients visited in the ENT outpatient department of our institute from where they were sent to department of pathology for fine needle aspiration cytology (FNAC). The clinical, radiological and histopathological features of the patients are given in (Table 1).

Clinical features: Out of the four patients, three were female and one was male. Age ranged from 30–45 years. All patients presented with the complaints of painless swelling over the hard palate for last 6–10 months. None of the cases had associated ulceration or any discharge (Figure 1). General examination of all patients did not reveal any significant findings. No history of chronic alcoholism or tobacco was given by any patient.

In all cases on examination there was a firm, smooth, non-tender, well circumscribed lesion in the middle of the hard palate. Overlying mucosa was healthy. No significant lymphadenopathy was found in the neck region.

Cytological features: Fine needle aspiration cytology of the lesion was performed and the smears were stained with Giemsa stain. Smears revealed the presence of bimodal pattern of epithelial cells and spindle cells in a myxoid stroma. The epithelial cells were of uniform size with round to oval nuclei, moderate amount of cytoplasm and well defined cell boundaries (Figure 2). A diagnosis of pleomorphic adenoma was made. All patients had surgery for removal of mass and tissues were sent for histopathological examination.

Histopathological features: Histopathological examination revealed a well encapsulated tumor outside which small amount of normal salivary gland tissue was seen (Figure 3A-B). Tumor tissue consisted of gland like structures and sheets of epithelial cells (Figure 4) (Figure 5) with myxoid (Figure 6A-B) and chondroid areas (Figure 4) (Figure 7). No mitotic figures were found. These features were consistent with diagnosis of a pleomorphic adenoma.

Tumors of minor salivary glands constitute 2–4% of the head and neck tumors and about 10% of tumors of oral cavity. [1] About 22% selivary gland tumors arise in the minor salivary glands. [2] [3] [4] Most common tumor of minor salivary glands is a pleomorphic adenoma. [5] Most common site for minor salivary gland pleomorphic adenoma is the hard palate followed by lip, buccal mucosa, floor of mouth, tongue tonsils, pharynx, retro molar area and oral cavity. [2] [4] In our study of four cases we found all arising from the palate.

Intraoral pleomorphic adenoma appears as slow growing painless mass, usually in the fourth or fifth decade. [6] Study done by Moshy et al. showed slight predilection for older patients. [5] On the other hand, study done by Waldrom et al. revealed that tumor was more common in younger age group. [7] These findings suggest a possible variation in the presentation of intraoral minor salivary gland tumors in different population. In our study, the tumor was found in fourth and fifth decade.

Most studies have shown that minor salivary gland tumors are more common in females than male. [8] Male to female ratio is 1:1.8 to 1:2.4. [9] [10] The tendency for female predominance is especially marked in benign tumors. [9] Our case series of four cases also underscores this fact.

Study done by Moshy et al. and Waldron et al. shows predominance of malignant neoplasm over benign ones, [5] [7] while other studies show higher number of benign salivary gland tumors than malignant ones. [8] [11] This difference may be because these studies are from major referral centre which receives all the referred and complicated cases. [8] [11] Therefore, we can conclude that relative incidence of benign versus malignant tumors reflects the character of each institute. Likewise, in our study also we found all cases to be benign, as our institute is having many referral hospitals nearby.

Pleomorphic adenoma of the palate although being a benign tumor has a high recurrence rate. Lack of well defined fibrous capsule is a feature most commonly associated with a high recurrence rate. [7]

The diagnosis of pleomorphic adenoma is suspected on the basis of history and physical examination and confirmed with cytology and histopathology. Comupted tomography scan and magnetic resonance imaging are helpful in providing information about the size and extension of the tumor to the surrounding structures. This tumor usually does not recur after adequate surgical removal.

We presented four cases of pleomorphic adenoma from one of the rare site of minor salivary gland tumor. These tumors should be evaluated thoroughly for any extension into deeper tissues. During surgery complete removal must be ensured so that tumor does not recur.

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