title: Medullary thyroid carcinoma presenting as rectangular cell type on fine-needle aspiration.
abstract: Medullary thyroid carcinoma typically presents as dyscohesive plasmacytoid, spindled, or polygonal cells on fine-needle aspiration smears. We recently encountered a case of sporadic medullary thyroid carcinoma that presented as a hypercellular aspirate composed of cohesive aggregates of rectangle-shaped cells. The case was mistakenly reported as a hypercellular follicular neoplasm on cytology. Subsequent thyroidectomy revealed medullary carcinoma. We draw attention to this distinctive rectangular cell type as an additional morphology for medullary thyroid carcinoma.
authors.affiliation: Department of Pathology and Laboratory Medicine, New York Presbyterian Hospital-Weill Cornell Medical Center, New York, New York 10065, USA. ams2033@med.cornell.edu
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Schreiner
authors.forename: Grace C H
authors.initials: GC
authors.lastname: Yang
mesh_terms: D000368:Aged; D044963:Biopsy, Fine-Needle; D018276:Carcinoma, Medullary / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D006801:Humans; D008297:Male; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000473:pathology