title: Fine-needle aspiration study of cystic papillary thyroid carcinoma: Rare cytological findings.
abstract: BACKGROUND
  Cystic papillary thyroid carcinoma (CPTC) is a variant of papillary carcinoma that has many mimickers in cytological grounds.
  
  
  OBJECTIVE
  To study the cytomorphologic features of CPTC and compare them to those of other cystic thyroid lesions using fine-needle aspiration cytology (FNAC). We also aimed to identify the cytomorphologic features that distinguish CPTC from other cystic thyroid lesions.
  
  
  METHODS
  Seventy-three cases of CPTC were included in the study. The cytomorphologic features of these cases were analyzed. The FNA smears of other thyroid lesions with cystic changes (300 colloid goiters, 290 adenomatoid nodules, 11 follicular neoplasms, and 9 hurtle cell neoplasm) were also studied.
  
  
  RESULTS
  The smears in CPTC revealed isolated follicular cells, small groups of cells with scalloped margins, cell swirls, small clusters with a cartwheel pattern, papillary clusters, intranuclear inclusions, nuclear grooves, sticky colloid, intracellular colloids, psammoma bodies, multinucleated giant cells, and foamy and hemosiderin laden macrophages. Small groups of cells with scalloped borders, cellular swirls, and small clusters with a cartwheel pattern were seen in CPTC, but not in other cystic lesions. Interestingly, mesothelial-like cells and hemophagocytic cells were seen in five and three cases of CPTC, respectively, but not in other cystic lesions.
  
  
  CONCLUSIONS
  Mesothelial-like cells and hemophagocytic cells were observed in five and three cases of CPTC, respectively. Similar finding have not been previously reported in the literature.
authors.affiliation: Department of Pathology, Shiraz Medical School, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Maral
authors.initials: M
authors.lastname: Mokhtari
authors.affiliation: Department of Pathology, Shiraz Medical School, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Perikala Vijayananda
authors.initials: PV
authors.lastname: Kumar
authors.affiliation: Department of Pathology, Shiraz Medical School, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Kamran
authors.initials: K
authors.lastname: Hayati
keywords: Cystic papillary carcinoma; fine-needle aspiration cytology (FNAC); hemophagocytosis; thyroid