Warthin's tumour: unusual vs. common morphological findings in fine needle aspiration biopsies

Abstract

Fine needle aspiration biopsies (FNA) of 47 Warthin's tumours confirmed by histology were re-evaluated for cytomorphological findings. The majority of aspirates (37/47) contained a typical background with proteinaceous substance and cell debris, along with cellular elements represented by oncocytic, lymphoid, and mast cells with degranulated cytoplasm. Uncommon cellular findings were true squamous cells (1/47), atypical cells with vacuoles (1/47), osteoclastic giant cells (1/47), epithelioid cells (1/47), mast cells with preserved granules in cytoplasm (3/47), and siderophages (4/47). Uncommon findings in the background were corpora amylacea-like structures and homogeneous bright red droplets. Squamous cells and atypical cells with vacuoles caused diagnostic difficulties in distinguishing a Warthin's tumour from a squamous cell or mucoepidermoid carcinoma. However, other unusual cellular and background findings were not worrying; therefore, they are merely regarded as a curiosity in the cytomorphological appearance of the tumour.

Is Surgery for an FNA proven Warthin's Tumor Passé?

“…The cytological accuracy was 81% (3 cases had a preoperative FNA suggesting a malignant tumor) [5]. In another study, 37 out of 47 patients (79%) had a correct FNA diagnosis confirmed by histology [6]. Similar to these results, the sensitivity in our series was 78.7%.…”

“…It typically presents as a slow-growing parotid mass. Squamous metaplastic cells may be identified in more than 60% of cases [5,6].…”

“…Although most previous studies analyzed Warthin tumor patients who underwent a pre-operative FNA [5][6][7][8], the risk of missing malignant tumors, falsely demonstrating a cytological benign Warthin tumor in the pre-operative FNA, is still slight. We present our experience in managing Warthin tumor and the accuracy of a pre-operative FNA-based diagnosis.…”

An algorithm for preoperative differential diagnostics of parotid tumours on the basis of their dynamic and diffusion-weighted magnetic resonance images: a retrospective analysis of 158 cases

“…However, a growing body of evidence suggest that this examination does not provide adequate diagnostic accuracy, especially in the case of small and/or deeply located lesions. In up to 5% of the cases, material obtained during biopsy of such tumours may be not representative enough to determine their character [6,14,16,23]. Moreover, an incorrectly performed biopsy may lead to various complications, including systemic spread of cancer cells and ascending infection of the head and neck [2,9].…”

Warthin Tumor with Signet-Ring Cell Features as a Pitfall in Salivary Gland Cytopathology

“…In a background rich with lymphocytes and granular debris, the recognition of oncocytic cells make the diagnosis straightforward and accurate, in most cases. On occasion, however, unusual features challenge even the experienced cytopathologist [1,2]. In particular, squamous or mucinous metaplasia changes may overlap with mucoepidermoid carcinoma features [1,2,3].…”