|Year : 2018 | Volume
| Issue : 5 | Page : 420-422
Primary pleomorphic adenoma of the parapharyngeal space
Shreeya Taresh Indulkar, Manisha Khare, Yasmeen Khatib, Yogita Mangaldas Talpade
Department of Pathology, HBT Medical College and Dr. R. N. Cooper Hospital, Mumbai, Maharashtra, India
|Date of Web Publication||5-Sep-2018|
Shreeya Taresh Indulkar
Department of Pathology, HBT Medical College and Dr. R. N. Cooper Hospital, Juhu, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
Parapharyngeal space (PPS) tumors are rare, accounting for 0.5% of all head-and-neck neoplasms. Most of them are benign and originate in the salivary glands. Pleomorphic adenoma is the most common benign salivary gland tumor originating from PPS. We report a case of a 32-year-old patient presented with the complaints of a snoring, excessive daytime sleepiness, and painless parapharyngeal mass from 3 to 4 years. As PPS tumors are difficult to diagnose early due to their complex anatomy and vague presentation, histopathological examination remains the gold standard for final diagnosis.
Keywords: Parapharyngeal space, parotid gland, pleomorphic adenoma
|How to cite this article:|
Indulkar ST, Khare M, Khatib Y, Talpade YM. Primary pleomorphic adenoma of the parapharyngeal space. Med J DY Patil Vidyapeeth 2018;11:420-2
| Introduction|| |
The parapharyngeal space (PPS) is an inverted cone-shaped fascial space of the suprahyoid neck extending from the base of the skull to the hyoid bone. It is further divided into prestyloid and poststyloid compartments by styloid process, and its attached muscles and fascia. It is one of the potential fascial planes of head-and-neck that may become involved by various infectious, inflammatory, and neoplastic pathological processes. PPS neoplasms are relatively rare and account for 0.5% of all head-and-neck neoplasms. Approximately 70%–80% of these tumors are benign. Among the PPS tumors, salivary glands neoplasms are most common followed by tumors of neurogenic origin and paraganglioma. Pleomorphic adenoma (PA) usually originate in the superficial lobe of parotid gland, but rarely, it may involve the deep lobe of the parotid gland, growing medially, and occupying the PPS. Parapharyngeal PAs may remain undetected for a long period and cause diagnostic difficulty.
| Case Report|| |
A 32-year-old male patient presented with the complaints of snoring, excessive daytime sleepiness since from 3 to 4 years. On oral examination, a smooth firm bulging mass was seen in the right tonsillar and paratonsillar region. No mucosal ulceration was seen. Computed tomography (CT) scan showed a well-defined mass in the right parapharyngeal region measuring 6.5 cm × 4.5 cm × 2.7 cm abutting the superior surface of the right submandibular gland and the deep lobe of right parotid gland inferioposteriorly. No other obvious mass/lymphadenopathy was noted. The patient underwent surgical excision of the lesion through the cervical-transparotid approach. The mass was removed as multiple large tissue fragments aggregating to 7 cm x 5 cm x 3 cm. It was predominantly cystic with few solid areas attached to the inner cyst wall [Figure 1]. Other tissue bits were firm, gray-white, irregular, and few were mucoid. Histopathological examination revealed a neoplasm with an admixture of epithelial and stromal components with extensive cystic change. The tumor showed ducts, tubules, and cords lined by inner epithelial cells surrounded by stellate and spindle myoepithelial cells in a fibromyxoid stroma [Figure 2]. Focal areas of hyalinization and calcification were also noted. The final diagnosis was PPS PA. Patient has been followed up postoperatively for 4 months and is disease free till date.
|Figure 1: Poorly circumscribed predominant cystic tumor with few solid gray-white areas|
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|Figure 2: (a) Benign epithelial elements composed of ducts and tubules in a chondromyxoid stroma (H and E, ×100). (b) High-power view of the ductal elements showing double-layered epithelium (H and E, ×400)|
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| Discussion|| |
Salivary gland tumors occupy the prestyloid PPS and account for 40%–50% of PPS lesions. PA is the most common benign tumor involving the PPS and accounts for 80%–90% of the salivary neoplasms in the PPS. PA involving the superficial lobe of the parotid gland can invade the deep lobe and may herniate through the stylomandibular membrane to involve the PPS. They can also arise through the displaced or aberrant salivary gland tissue within a lymph node. Rarely, PA can arise de novo from the minor salivary gland in the PPS as seen in this case.
These tumors usually present as a submucosal swelling and other varied symptoms of a parapharyngeal mass lesion, i.e., otalgia, neuralgia, cranial nerve deficits, or trismus can be seen. However, in some cases, the patient may present with snoring and obstructive sleep apnea syndrome due to the huge size of the tumor compressing the paratonsillar and tonsillar areas. In our case, as the symptoms progressed gradually, the patient presented late when the mass size was large enough to be visible in the oral cavity.
Fine-needle aspiration cytology (FNAC) is the modality of choice for obtaining the sample for diagnosis. In this case, patient preferred direct excision rather than FNAC for diagnosis. In PPS tumors, 25% of intraoral FNAC may not be diagnostic because of the lack of adequate cellular material. CT scan and magnetic resonance imaging are vital tools to demonstrate the dimensions, the extent of tumor, type, and invasion into surrounding structures. However, incision biopsy is not beneficial due to the risk of tumor dissemination and subsequent recurrence.,
Grossly, most of PA at PPS, are well circumscribed, lobulated with a homogenous gray-white cut surface. In this case, the tumor was predominantly cystic. These tumors are poorly capsulated, and the false capsule results due to fibrosis of the surrounding normal parenchyma. On microscopy, PA is an epithelial tumor showing epithelial and myoepithelial components arranged in different patterns against a mucopolysaccharide stroma. The risk of developing carcinoma ex-PA from this benign tumor is 5%–6% over twenty years. The incidence of malignant transformation depends on duration of tumor which is about 2% for tumors present <5 years and 10% for those more than 15 years.,
Various surgical approaches for removal of the tumor include transparotid, transcervical, and transmandibular routes. The surgical approach providing wide intraoperative visibility for safe radical dissection, minimal functional, and cosmetic after-effects is ideal for excision. In this case, the excision through cervical transparotid approach was preferred as there is lesser morbidity as compared with the historical direct path through mandibulectomy. Although these tumors are well encapsulated, resection with adequate margins of normal tissue is necessary to prevent local recurrence. In this case, the tumor was received in multiple bits; no comment on the surgical margin could be made. According to the study by Mendelsohn et al., the recurrence rate is 8%, and all the reported recurrences occurred within 5 years of resection.
| Conclusion|| |
Due to the complex anatomy, location and vital structures in the vicinity, resection of PPS tumors can prove challenging. PA arising de novo in the PPS is rare. An adequate clearance of the tumor with surrounding dispensable normal tissues is the key to successful treatment of such tumors.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]