title: Thyroid hemiagenesis associated with medullary or papillary carcinoma: report of cases.
abstract: BACKGROUND
  Thyroid hemiagenesis is a rare congenital anomaly in which 1 thyroid lobe fails to develop. Co-occurrence of hemiagenesis and thyroid carcinoma is extremely rare. Here, we report 2 cases of thyroid hemiagenesis with carcinoma.
  
  
  METHODS
  The first patient was referred with a left thyroid mass and absent right lobe. The frozen section examination revealed medullary thyroid carcinoma (MTC); therefore, a left thyroid lobectomy plus neck dissection was performed. Another patient was referred with a right thyroid mass and absent left lobe. Fine-needle aspiration biopsy was suspicious for papillary carcinoma. The patient underwent right thyroid lobectomy plus neck dissection.
  
  
  RESULTS
  The operative findings confirmed hemiagenesis of the right lobe and MTC in the left lobe for the first case, and hemiagenesis of the left lobe and papillary carcinoma in the right lobe for the second case.
  
  
  CONCLUSIONS
  Our case represents the first reported case of association between thyroid hemiagenesis and MTC.
authors.affiliation: Department of Head and Neck Surgery, Institute of Minimally Invasive Surgery of Zhejiang University, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
authors.forename: Jianbiao
authors.initials: J
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Gao
authors.forename: Chunyi
authors.initials: C
authors.lastname: Song
mesh_terms: D044963:Biopsy, Fine-Needle; D018278:Carcinoma, Neuroendocrine; D002291:Carcinoma, Papillary / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D037981:Neck Dissection; D035583:Rare Diseases; D018570:Risk Assessment; D013961:Thyroid Gland / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler
keywords: embryologic anomaly; medullary carcinoma; papillary carcinoma; thyroid disease; thyroid hemiagenesis