A 42-year-old Nigerian male was referred to the outpatient clinic of the Oral and Maxillofacial Surgery Department of the Lagos University Teaching Hospital in May 2002 with a painless, slow growing recurrent left neck mass of 20 years, duration without any associated constitutional symptoms. There was no history of difficulty in swallowing. He had undergone surgical resection for the similar neck mass earlier in 1972 and 1982, which was diagnosed as pleomorphic adenoma. The patient gave a history of tuberculosis in 1973 and regular visit to the psychiatrist. Clinical examination revealed a firm non-tender multilobulated mass in the left submandibular region. The overlying skin appeared clinically normal with the incision scar of previous surgeries. Intra-oral examination revealed a firm non-tender bulge on the left parapharyngeal/tonsilar fossa. Bimanual palpation of the left parotid gland revealed no abnormalities. A provisional clinical diagnosis of pleomorphic adenoma or Warthin's tumor involving the left parapharyngeal space and submandibular gland was made.
Incision biopsy of the submandibular discrete lobule confirmed the diagnosis pleomorphic adenoma. Computed tomographic (CT) scan could not be done, as the patient could not afford the cost, while magnetic resonance imaging (MRI) facilities are not available at our centre.
The patient was subsequently admitted for surgical excision of the submandibular and parapharyngeal tumor. The submandibular lesion was approached through a left submandibular incision. The mass was found to be completely distinct from the parapharyngeal tumor, which was enucleated by blunt dissection. Recovery and immediate post-operative period were uneventful.
On gross examination, the submandibular tumor consisted of multiple nodules of solid, well encapsulated masses ranging from 1 to 4 cm (figure 1). While the parapharyngeal mass measured 8 cm x 4 cm x 2 cm and was well encapsulated (figure 2). Histological examination confirmed the diagnosis of pleomorphic adenoma (figure 3 and figure 4). Both lesions exhibited dense fibrous connective tissue stroma in which sheets and nests of neoplastic epithelium and epithelial lined ductal structures containing eosinophilic coagulum were seen. Myoepithelial cells were seen in a myxochondroid area. These were more prominent in the parapharyngeal tumor. Both lesions also contained squamous metaplasia and keratin pearl formation. Myxoid areas were predominant in the submandibular tumor. The stroma of the submandibular tumor showed hyalinization. There was no evidence of malignancy in any of the sections examined.