PMA -Pleomorphic adenoma, FNAC - Fine needle aspiration biopsy, ACC -Adeniod cystic carcinoma, RT -Radiotherapy,NM - Not Mentioned, NAD -No abnormality detected.
The present tumor was also, provisionally described as a lymphoepithelial cyst or Warthins tumor on the CECT examination. Predicting a benign neoplasm with negligible metastatic potential, the case was surgically managed by a minimally invasive option of superficial parotidectomy with facial nerve preservation. The pathology was disparate from the pre-operative diagnosis and reported as the rare polymorphous low-grade adenocarcinoma of the parotid gland. It was concluded to be the classical variant as per the WHO 2017 classification due to clinical evidence of slow growth with the absence of local or distant metastasis over the last 10 years and the presence of small to medium cells in multiple patterns, targetoid cells, and <30 % of cribriform areas.4 It was further confirmed by the diffuse positivity for the S-100 stain, which is reported to be associated with more than 90 % of reported cases.16
The recommended treatment of PLGA, independent of its location, consists of the wide local surgical excision, and neck dissection should be added only in cases with cervical lymphadenopathy.17 The complete surgical excision of the parotid gland was not accomplished for the present case as the initial treatment plan was framed, considering it a benign lesion. The role of postoperative radiotherapy is ambiguous in the treatment of PLGA. It may diminish the local recurrence of tumors having high-risk features, closed margins, perineural invasion, etc [6]. However, the recurrence might take years to develop in PLGAs without adverse features with negative or even positive margins.6,17 The main limitation of the present case is the non-accomplishment of radiotherapy due to the patient’s denial. As the tumor was a classical variant suspected to have an indolent course and the postoperative CT scan also recorded minimal residual disease, he is kept under the regular three-month follow-up to detect the earliest sign of any anticipated complications.
CONCLUSION AND RESULTS
PLGA of the parotid gland is a rare entity in the Asian population with diverse morphology and cytological patterns. The available pre-operative investigations have a limited role in its diagnosis, and a detailed histopathological examination is the standard for confirmation.
AUTHOR CONTRIBUTION: IPK, PD, MS Conceptualization; data curation; resources; software; writing – original draft; writing – review and editing. VP, AM, JS, NS Conceptualization; formal analysis; supervision; writing – original draft; writing – review and editing. All authors agreed to the final version of the manuscript.