Metaplastic (infarcted) Warthin's tumour of the parotid gland: a possible consequence of fine needle aspiration biopsy

Focal sarcoid-like change of the thyroid gland. A possible consequence of aspiration cytology?

An unusual case of focal accumulation of sarcoid-like granulomas occurring within the thyroid gland of a 43-year-old female patient is reported. The granulomas were found solely at the site of previous fine needle aspiration biopsy. The follow-up did not show any symptoms of systemic granulomatous disease. The pathogenesis of this lesion is discussed.

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

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.

Parotid Warthin's tumour Bristol Royal Infirmary (1985-1995): a study of histopathology in 33 cases

This is a study of 33 (32 patients) confirmed Warthin's tumours (adenolymphomas) treated surgically at Bristol Royal Infirmary (1985--1995) focussing specifically upon 17 salient histopathological features together with capsular measurement by micrometry. Twenty-four out of 33 tumours had 'thin' capsules (< or = 200 microm), whereas 5/9 'thick' capsules were associated with gross tumour degeneration. The degenerative features including cystic change, squamous metaplasia, corpora amylacea like bodies, etc. were quantified. Tumours were classified into subtypes (typical, stroma poor, etc). These variations were not associated with age or sex. In 20/33 tumours a marginal sinus suggested a lymph node origin. Fine needle aspiration cytology (FNA) smears showing degeneration features are a diagnostic problem, but histopathological features are reflected in such smears and their recognition enhances diagnostic precision, enabling controlled surgical enucleation, the ideal operation, to be performed in most cases. In this study only 12 tumours were so treated; 11 others received parotidectomy. The theories of histogenesis are reviewed and discussed.

Cytokeratin expression and epithelial differentiation in Warthin's tumour and its metaplastic (infarcted) variant

AIMS

Warthin's tumour is characterized by a bilayered columnar epithelium. Transformation into metaplastic (infarcted) Warthin's tumour includes squamous metaplasia of the epithelium along with regressive changes in the stroma. Misinterpretation of metaplastic Warthin's tumour for malignancy is a serious diagnostic pitfall. This study assesses the utility of cytokeratin expression in Warthin's tumour and its metaplastic variant.

METHODS AND RESULTS

Twenty-six cases of Warthin's tumour, among them eight metaplastic Warthin's tumours, were investigated employing immunohistochemistry. Both Warthin's tumour and its metaplastic variant regularly expressed cytokeratins (CK) 7, 8, 18, and 19. Staining results with antibodies to CK10, 10/13, 1/2/10/11, and 20 were negative in all specimens. Immunoreactivity for CK 5/14 and 17 was restricted to basal cells in Warthin's tumour, but involved basal as well as surface cells in metaplastic Warthin's tumour.

CONCLUSIONS

Warthin's tumour and its metaplastic (infarcted) variant both express CK 7, 8, 18, and 19, which are typical for columnar differentiation. Cytokeratins typical of squamous differentiation are absent from Warthin's tumour and its metaplastic variant, irrespective of the squamous morphology of the epithelium in metaplastic Warthin's tumour. The expression of CK 5/14 and 17, which are typical of regenerative cells, is restricted to basal cells in Warthin's tumour, but is expressed also in surface cells in metaplastic Warthin's tumour.

Tissue effects of salivary gland fine-needle aspiration. Does this procedure preclude accurate histologic diagnosis?

Recent reports have alluded to various tissue effects secondary to fine-needle aspiration (FNA), particularly infarction observed in resected salivary gland masses, precluding accurate histologic diagnosis. Our experience with the use of 25-gauge needles indicates otherwise. We retrospectively reviewed 94 resected salivary gland masses previously sampled by FNA, looking for infarction, hemorrhage, needle track tumor seeding, and fibrosis. We assessed the significance of these complications and their impact on the histologic diagnosis. The median interval from FNA to excision was 25 days. Variable degrees of infarction and hemorrhage were present in 7 cases (7%) and 9 cases (10%), respectively. Infarction ranged from 5% to 80% (average, 20%), while hemorrhage averaged less than 20% of the material on the tissue sections. Significant infarction was present in acinic cell carcinomas (3/7), but histologic diagnosis was not compromised, and tissue alterations were absent. We conclude that FNA of salivary gland lesions using 25-gauge needles is safe and does not significantly alter the histologic diagnosis. The tissue effects observed did not preclude accurate diagnostic interpretation in any case.

Malignancy-simulating change in parotid gland oncocytoma following fine needle aspiration. Report of 3 cases

We report here there cases of benign parotid gland oncocytoma with pseudomalignant change that mimic acinic cell carcinoma. All patients underwent fine-needle aspiration biopsy of the tumor 62, 725 and 33 days before surgical excision. In histologic sections, there were clusters of pigmented cells with PAS-positive foamy to finely granular cytoplasm similar to those seen in salivary gland acinic cell carcinomas. This report provides another, previously undescribed, example of a diagnostic pitfall that may be observed in histologic tissue specimens removed after FNA of oncocytic tumors.