title: Ectopic thymoma can mimic benign and malignant thyroid lesions on fine needle aspiration cytology: a case report and literature review.
abstract: BACKGROUND
  Ectopic cervical thymomas are rare and there are few descriptions of the cytologic findings based on fine needle aspiration. Their appearances can be misinterpreted as either benign or malignant lesions of the thyroid. The authors report such a case occurring in a patient with Sotos syndrome, a genetic disorder characterized by somatic overgrowth and cognitive impairment.
  
  
  METHODS
  The patient developed a neck mass that was examined first by fine needle aspiration and then by pathologic examination of the resected specimen. On fine needle aspiration, a diagnosis of papillary carcinoma of the thyroid was favoured, based on the presence of large cohesive sheets of anastomosing papillary tissue fragments with fibrovascular cores. Pathologic examination of the resection specimen showed a thymoma, subtype B3. The cytologic findings correlated with the presence of nuclear palisading of tumour cells around perivascular spaces.
  
  
  CONCLUSIONS
  To the best of our knowledge, this histologic subtype of thymoma has never been reported in ectopic cervical thymic tissue, nor these particular cytologic findings that can lead to an erroneous diagnosis of thyroid carcinoma. Moreover, this is the first description of thymoma in association with Sotos syndrome.
authors: Department of Pathology, Chulalongkorn University, Bangkok, Thailand.
authors: Mana
authors: M
authors: Taweevisit
authors: Pichet
authors: P
authors: Sampatanukul
authors: Paul Scott
authors: PS
authors: Thorner
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000473:pathology*; D002291:Carcinoma, Papillary; D002828:Choristoma / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008477:Mediastinal Diseases / Q000473:pathology*; D008875:Middle Aged; D009333:Neck; D009375:Neoplasms, Glandular and Epithelial / Q000737:chemistry / Q000473:pathology* / Q000628:therapy; D011237:Predictive Value of Tests; D058495:Sotos Syndrome / Q000473:pathology; D013950:Thymus Gland; D013953:Thymus Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000628:therapy; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor