title: Secondary tumors involving the thyroid gland: A multi-institutional analysis of 28 cases diagnosed on fine-needle aspiration.
abstract: BACKGROUND
  Fine-needle aspiration (FNA) is routinely used to evaluate primary thyroid lesions (PTLs), however, its role in diagnosing secondary thyroid neoplasms (STNs) has not been extensively studied. The goal was to examine the clinical and cytopathologic features of STNs diagnosed on FNA.
  
  
  METHODS
  The clinico-pathologic features of 28 STNs were analyzed. All PTLs, lymphomas, and locally invasive tumors were excluded.
  
  
  RESULTS
  There were 28 STNs (0.18% incidence) out of 15,800 thyroid FNAs (12 males, 16 females, 32 - 85 years), all occurring metachronously (3 weeks-20 years, average 78.3 months) comprising 24 (85.7%) metastatic carcinomas (14 [50%] renal; 4 [14.3%] head and neck squamous cell carcinomas, 3 [10.7%] breast, and 1 [3.6%] colorectal, uterine serous carcinoma, and lung adenosquamous carcinoma, respectively), 3 sarcomas (10.7%) and 1 melanoma (3.6%).
  
  
  CONCLUSIONS
  STNs are rare and diverse tumors which may occur decades after primary malignancy. Renal carcinomas are the most common. Prior history of malignancy, high index of suspicion, and attention to key distinguishing cytologic clues are critical for accurate diagnosis.
authors: Department of Pathology, Louisiana State University Health Sciences Center, Shreveport, Los Angeles.
authors: Kim
authors: K
authors: HooKim
authors: Department of Biology, Georgia State University, Atlanta, Georgia.
authors: Jennifer
authors: J
authors: Gaitor
authors: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York.
authors: Oscar
authors: O
authors: Lin
authors: Department of Pathology, Emory University School of Medicine, Weill Cornell Medical College, Atlanta, Georgia.
authors: Michelle D
authors: MD
authors: Reid
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle / Q000379:methods; D002292:Carcinoma, Renal Cell / Q000175:diagnosis / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000473:pathology*; D008175:Lung Neoplasms / Q000175:diagnosis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D013961:Thyroid Gland / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000556:secondary
keywords: cytology; fine-needle aspiration; metastasis; secondary thyroid neoplasm; thyroid