Incidental finding of synchronous pleomorphic salivary adenoma and Warthin’s tumour within a parotid gland

Abstract

The presence of two histologically distinct lesions within the same salivary gland is rare. The majority of lesions detected in salivary glands are benign and unifocal. Ultrasound scans and MRI imaging may not detect separate lesions that are in close proximity and this presents a challenge for radiologists and surgeons in the diagnosis of salivary gland lesions. We present a case when incidentally two distinct lesions were discovered during extracapsular dissection of a suspected pleomorphic salivary adenoma. We aim to highlight the difficulty in diagnosing these rare entities using existing investigative techniques.

Uncommon Coexistence of Pleomorphic Adenoma and Warthin’s Tumor in a Painfully Swollen Left Parotid Gland: A Surgical Case Report

“…In either case the vast majority of multiple neoplasms of the parotid gland are identical in histology, namely WT [ 11 , 13 ]. However, simultaneous occurrence of multiple parotid tumors of different entities is rare and clinical experience on this subject is largely based on single case reports [ 7 – 10 , 18 ]. In such cases the tumors are, considering their high prevalence, ordinarily a combination of WT and PA [ 11 , 13 , 18 ].…”

“…Although clinical diagnosis by imaging methods such as MRI and ultrasound is usually successful in locating and assessing the malignant potential of singular/bilateral lesions of the parotid glands, the difficulty of correct preoperative radiological assessment of multiple ipsilateral parotid tumors is well known [ 7 , 19 ]. A definitive diagnosis is usually made only during histological tissue examination, as in the present case [ 7 , 11 ].…”

“…Although clinical diagnosis by imaging methods such as MRI and ultrasound is usually successful in locating and assessing the malignant potential of singular/bilateral lesions of the parotid glands, the difficulty of correct preoperative radiological assessment of multiple ipsilateral parotid tumors is well known [ 7 , 19 ]. A definitive diagnosis is usually made only during histological tissue examination, as in the present case [ 7 , 11 ]. It should be emphasized that even a correct preoperative determination of a single tumor entity by means of fine-needle aspiration cytology (FNAC) can be misleading in patients with multiple tumors with different histology, as the second intact tumor entity in situ cannot be taken into account by the pathologist [ 7 , 8 ].…”

“…A definitive diagnosis is usually made only during histological tissue examination, as in the present case [ 7 , 11 ]. It should be emphasized that even a correct preoperative determination of a single tumor entity by means of fine-needle aspiration cytology (FNAC) can be misleading in patients with multiple tumors with different histology, as the second intact tumor entity in situ cannot be taken into account by the pathologist [ 7 , 8 ]. In our case, non-invasive imaging (MRI) but no FNAC or other histological confirmation was performed prior to surgery, because even in benign tumors of the salivary glands, the masses including their capsule should be completely removed to avoid recurrences.…”

“…Although tumors of the salivary glands usually occur as solitary lesions, multiple parotid tumors have been reported in the literature [ 7 – 15 ]. Depending on the underlying patient population and therefore based on different incidences, multiple parotid tumors have been described with frequencies of 3.4% (Yu et al; cohort of 2055 patients, Peking) up to 5% (Ethunandan et al; cohort of 606 patients, Chichester) [ 11 , 13 ].…”