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Thyroid. 2017 Dec;27(12):1498-1504. doi: 10.1089/thy.2017.0280. Epub 2017 Nov 7.

Pathologic Reporting of Tall-Cell Variant of Papillary Thyroid Cancer: Have We Reached a Consensus?

Author information

1 Department of Anatomic Pathology, Moffitt Cancer Center , Tampa, Florida.
2 Thyroid, Head and Neck Cancer (THANC) Foundation , New York, New York.
3 Department of Pathology, Laboratory Medicine Program, University Health System , Toronto, Canada .
4 Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania , Philadelphia, Pennsylvania.
5 Department of Pathology, Massachusetts General Hospital , Boston, Massachusetts.
6 Department of Pathology, Memorial Sloan-Kettering Cancer Center , New York, New York.
7 Department of Pathology and Laboratory Medicine, University of Wisconsin , Madison, Wisconsin.
8 Department of Pathology, The University of Pittsburgh Medical Center , Pittsburgh, Pennsylvania.
9 Department of Pathology, Medical College of Wisconsin , Milwaukee, Wisconsin.
10 Department of Pathology, Woodland Hills Medical Center , Woodland Hills, California.
11 Department of Pathology, New York-Presbyterian/Columbia , New York, New York.
12 Department of Otolaryngology-Head and Neck Surgery, Mount Sinai Beth Israel , New York, New York.



Tall-cell variant (TCV) is widely believed to be a more aggressive subtype of papillary thyroid carcinoma (PTC). Despite the significance of TCV with respect to risk stratification and therapeutic decision making, its diagnosis is subject to inter-observer variability. This study aimed to determine the level of agreement among expert pathologists in the identification and reporting of TCV.


Seventeen surgical resections for thyroid cancer containing the diagnostic term "tall cell" in their pathology reports and 22 cases diagnosed as classical PTC were selected. Cases were digitalized, and 14 expert pathologists reviewed the scanned slides blinded to the original interpretation. Each pathologist designated each case as TCV or not and answered multiple questions about diagnostic histopathologic features of TCV.


The overall strength of agreement for identifying TCV was fair (Fleiss kappa 0.34), and the proportion of observed agreement was 0.70. Of 22 cases originally diagnosed as PTC classical variant, 15 (68%) were reclassified as TCV by at least one expert pathologist. It was noted that four different definitions for TCV were used by the participants based on various combinations of cell height to width (H:W) ratio and the percentage of tumor cells showing that specific ratio. All pathologists agreed that the diagnosis of TCV does not rely solely on a specific H:W ratio.


Pathologic reporting of TCV varies among pathologists. This disagreement is a result of the lack of unanimous diagnostic criteria and variation in individual pathologists' interpretations. These discrepancies lead to over- and under-diagnosis of TCV, which has significant implications in patient management. It is imperative to understand this variability in diagnosis TCV as it relates to risk stratification and interpretation of clinical studies related to this histologic subtype of PTC. Further studies are needed to reach consensus on the diagnostic criteria of TCV.


consensus; inter-observer variability; papillary thyroid cancer; pathologic reporting; tall-cell variant

[Indexed for MEDLINE]

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