Journal of Rare Disorders: Diagnosis & Therapy

Keywords

Sleep-disorderd breathing; Palatine mass; Pleomorphic adenoma

Introduction

Pleomorphic adenoma is a common salivary benign tumor mostly affecting parotid glands. It draws its name from its histological architecture which can be subdivided in three types: classical, myxoid and hypercellular. The myxoid type accounts for more than half of cases. In the major salivary glands, the tumor is enclosed by a layer of fibrous tissue termed a capsule. Incomplete capsule is observed in 33-49% of pleomorphic adenomas [1]. A small minority of tumors are located in the oral and nasal cavity [2]. They appear as slowly growing mass usually without symptoms. The differential diagnosis includes abscess, cysts, fibroma, lipoma, neurofibroma or squamous cell carcinoma [3,4]. Tumour spillage increases the risk of recurrence. Meticulous surgical excision with capsular integrity is the treatment of first choice. Recurrence is described in about 46% of cases and risk of malignant transformation in 3.3 to 13% [1]. It is rarely associated with obstructive sleep-disordered breathing. Obstructive sleep apnea (OSA) is a common well recognised entity mainly caused by obesity. The Apnea-Hypopnea Index (AHI) is defined as the number of apneas or hypopneas per hour of sleep and is mapped to disease severity [5]. Patients are considered to have OSA if their AHI is greater than 15 or if they have minimum oxygen saturation below 90 (American Academy of Sleep Medicine). In 1981, Moses et al. first reported a patient with OSA caused by nasopharyngeal carcinoma [6]. Since then 30 articles about tumors of the upper aerodigestive tract causing sleep disorder have been published [7,8]. Rada et al. studied the relationships between OSA and head and neck tumors [9]. The most frequent localisations were salivary gland, larynx, nasopharynx and oropharynx. There were 16 benign and 8 malignant neoplasms. The most frequent benign neoplasm related to OSA were lipomas. Among malignant lesions the most common were squamous cell carcinoma and non-Hodgkins lymphoma. We report a case of pleomorphic adenoma of the soft palate causing OSA and make a literature review.

Case Report

A 62-year-old woman was addressed to Ear Nose and Throat (ENT) consultation because of sleep obstructive breathing disordered symptoms including snoring and daytime fatigue.

She was non-smoker and had a social alcohol consumption. The ENT work-up included clinical exam, head and neck computed tomographic scan and sleeping test. On physical exam we discovered a submucosal mass of the right soft palate crossing the midline (Figure 1). The patient had a good oral care and satisfactory dental condition. There was no mucous lesion in the oral cavity and no cervical lymph node. The rest of the ENT exam was normal. The computed tomographic scan identified a mass of 3 × 2.4 × 2.3 cm in the soft palate without invasion of the adjacent tissues (Figure 2). Preoperative polygraphy confirmed OSA with AHI of 17, 2 per hour (Table 1). Therapy consisted of surgical tumor removal preserving the soft palate (Figure 3). No OSA surgery was performed. The defect of the soft palate was treated by primary closure without reconstruction. Histopathology concluded to entirely resected pleomorphic adenoma (Figure 4). Soft palate healed without complication (Figure 5). Snoring during night disappeared. Postoperative polygraphy realised 6 months later confirmed normal sleep with AHI of 5, 9 per hour (Figure 6 and Table 1).

Figure 1: Oropharyngeal examination: submucosal mass of the right soft palate crossing the midline.

Figure 2: Sagittal view of CT scan. Mass in the soft palate, measuring 3 x 2.4 x 2.3 cm.

Table 1: Pre- and postoperative polygraphy, AHI=Apnea- Hypopnea Index, ODI=Oxygen Desaturation Index.

Figure 3: Endoscopic view during tumor resection.

Figure 4: Microscopy analysis findings confirm pleomorphic adenoma.

Figure 5: Endoscopic view of soft palate at 1 month of follow.

Figure 6: Macroscopic specimen resected.

Discussion

Pleomorphic adenoma accounts for approximately 60% of all salivary gland neoplasms [10]. A small minority of tumors are located in the oral cavity, neck and nasal cavity [4,11]. In those localisations it appears as slowly growing painless mass [9] usually in the fourth or fifth decade of life, with a higher frequency in female [4,1]. The diagnosis is established on the basis of history, physical examination and histopathology [12]. Computed tomography scan and MRI can provide information on the location and size of the tumor, besides extension to surrounding structures [13,14]. Treatment consists of surgical tumor excision and/or continuous positive airway pressure [9]. Recurrence is rare after complete removal and the prognosis is excellent [15-17]. In the English-language literature, nine articles relate pleomorphic adenomas causing OSA; five cases of deep-lobe parotid tumors extending into the parapharyn-geal space [18-22], four cases arising from the minor salivary gland in the oral cavity and pharynx [23-27]. Tumors of the upper aerodigestive tract causing secondary OSA have been rarely reported in large series. Rada et al. [9] make a review finding only 30 articles about OSA caused by head-and-neck tumors, including 16 benign and 8 malignant neoplasms. Payne et al. [27] conclude that 13 of 17 (76.4%) patients with oral and oropharyngeal cancer have OSA. The most common symptom is sudden aggravation of snoring or gasping during night [17,27].

Conclusion

All patients with sleep disordered breathing should undergo a thorough ENT clinical examination [12,21]. Oral cavity and oropharyngeal tumors belong to the differential diagnosis of OSA. Sudden aggravation of snoring should raise suspicion of an oropharyngeal tumor.

References

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