title: Warthin tumor with signet-ring cell features as a pitfall in salivary gland cytopathology.
abstract: BACKGROUND
  Warthin tumor (WT) is a common parotid lesion reliably diagnosed by fine-needle aspiration (FNA). Worrisome metaplastic changes may occur in WT. Their interpretation as mucoepidermoid carcinoma represents a diagnostic pitfall. Moreover, WT and mucoepidermoid carcinoma may coexist, making this distinction difficult. So it is worthwhile to report unusual WT features. We describe a WT with signet-ring cells (SRCs).
  
  
  METHODS
  A 61-year-old male presenting with a 3.6-cm right parotid gland mass underwent FNA with rapid on-site evaluation. DiffQuik-stained smears showed groups of oncocytic cells with abundant granular cytoplasm in a background rich with debris, foamy macrophages and lymphoid cells. SRCs were observed on Papanicolaou-stained smears prepared from a second pass. A WT with SRC features was diagnosed. Histology revealed a WT with post-FNA infarctual changes.
  
  
  CONCLUSIONS
  To avoid false-positive diagnoses, the cytopathologist should be aware that SRC features may occur in WT. The concomitant presence of oncocytes and SRCs is useful to correctly diagnose this unusual WT variant.
authors: Department of Biomorphological and Functional Sciences, University Federico II, Naples, Italy.
authors: Claudio
authors: C
authors: Bellevicine
authors: Antonino
authors: A
authors: Iaccarino
authors: Umberto
authors: U
authors: Malapelle
authors: Giancarlo
authors: G
authors: Troncone
mesh_terms: D000235:Adenolymphoma / Q000473:pathology* / Q000601:surgery; D044963:Biopsy, Fine-Needle; D018279:Carcinoma, Signet Ring Cell / Q000473:pathology* / Q000601:surgery; D003581:Cytodiagnosis / Q000379:methods; D003951:Diagnostic Errors / Q000517:prevention & control; D005189:False Positive Reactions; D005487:Foam Cells / Q000473:pathology; D006801:Humans; D008214:Lymphocytes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D018193:Neoplasms, Complex and Mixed / Q000473:pathology* / Q000601:surgery; D010307:Parotid Neoplasms / Q000473:pathology* / Q000601:surgery; D011237:Predictive Value of Tests; D013194:Staining and Labeling