Gross: Small, poorly encapsulated, grayish lesions.
Microscopy: Cells composed of dark compact nuclei with scanty cytoplasm disposed in tubular, solid and cribriform patterns. Intercellular spaces are filled with hyaline material which is thought to represent excess basement membrane.
Swelling which may be associated with pain e/o nerve paralysis. Occasionally, trismus, temporomandibular joint dysfunction,discoloured saliva, formication may be the presenting feature.
FNAC may be done to obtain a histological diagnosis.
MRI Scan is particularly useful in differentiating a neoplasm of the deep lobe of the parotid from a parapharyngeal tumour by demonstration of fat planes.It also helps to identify involvement of vital structures and assess operability. Staging is usually done according to AJCC recommendations (TNM) .
Superficial/total parotidectomy – depending on the lobe involved. Facial nerve is sacrificed if paralysis is present pre operatively,if the nerve is encased by the tumour or if preservation would mean leaving behind gross residual disease. Presence of pulmonary metastasis is not a contra indication to surgery. Facial nerve function may be preserved by direct resuturing, nerve grafting or by dynamic muscle transfer.
Post operative radiotherapy is usually necessary ; especially when there is extraglandular disease, perineural invasion, direct invasion of regional structures and high grade histology. Adverse effects include mucositis and xerostomia.
Post operative chemotherapy is indicated if there is evidence of visceral spread. A combination of cisplatin, adriamycin and cyclophosphamide is usually preferred.
Neutron radiotherapy is an improvement over conventional radiotherapy. Here, neutrons are generated by accelerating protons or deuterons and impacting them on a beryllium target. The indications are nearly similar but local control can be achieved in 56 % of patients compared to 17 % for the latter. The five year survival rate is nearly 60 % for those with these tumours.
Dr.Vijay. R, P.G.Trainee – General Surgery, Room No. B-36, P.G. Annexe, Kozhikode Medical College, Kozhikode – 8.
D.P.Rajan (Associate Professor) Department of General Surgery, Kozhikode Medical College.