title: Cytologic features of hyalinizing trabecular adenoma of the thyroid.
abstract: OBJECTIVE
  To clarify the cytologic findings of hyalinizing trabecular adenoma (HTA) in order to reduce erroneous diagnoses of papillary carcinoma.
  
  
  METHODS
  Review of aspiration cytologic smears of 16 HTA cases and comparison with those of 20 papillary carcinoma cases.
  
  
  RESULTS
  The smears from HTA were slightly cellular, and 5 of 16 cases were insufficient for evaluation. Vague, curved nuclear palisading, radiating arrangement surrounding hyaline materials and yellow bodies were observed in 9 (81.8%) of 11 cases that had sufficient material. The tumor cells were mainly spindled; elongated, polygonal and stellate cells were also seen. In 9 of 11 cases, tumor cells with cytoplasmic processes were occasionally observed. The cytoplasm was faintly stained and somewhat filamentous. The cell border was indistinct. Neither papillary nor follicular structures were seen. Intranuclear cytoplasmic inclusions were identified in 100% of HTA and 75% of papillary carcinomas. The incidences of nuclear grooves in HTA and papillary carcinoma were 81.8% and 100%, respectively.
  
  
  CONCLUSIONS
  Cytologic findings indicating HTA are vague, curved nuclear palsiading; radiating arrangement surrounding hyaline material; elongated cells; cell processes; ill-defined cell border; faintly stained and filamentous cytoplasm; yellow bodies; and hyaline material in the background. All are useful cytologic characteristics in distinguishing HTA from papillary carcinoma. A lack of papillary architecture and sheetlike arrangement may also suggest HTA rather than papillary carcinoma.
authors.affiliation: Kuma Hospital, Kobe. skuma@basic.med.tokushima-u.ac.jp
authors.forename: Seiji
authors.initials: S
authors.lastname: Kuma
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Hirokawa
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
authors.forename: Kennichi
authors.initials: K
authors.lastname: Kakudo
authors.forename: Shoichi
authors.initials: S
authors.lastname: Katayama
mesh_terms: D000236:Adenoma / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D002291:Carcinoma, Papillary / Q000473:pathology; D002467:Cell Nucleus / Q000473:pathology; D003593:Cytoplasm / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006818:Hyalin / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology*