Defining Papillary Carcinoma of the Thyroid: A Short Review and Analysis

Solid Thyroid Follicular Nodules With Longitudinal Nuclear Grooves: Clinicopathologic, Immunohistochemical, and Molecular Genetic Study of 18 Cases

CONTEXT.—

Follicular thyroid nodules can be a source of diagnostic difficulties, particularly when they display atypical features commonly associated with malignancy, such as nuclear grooves.

OBJECTIVE.—

To differentiate lesions with atypical features from similar-appearing benign and malignant lesions.

DESIGN.—

Eighteen cases of atypical follicular thyroid nodules characterized by a solid growth pattern and prominent longitudinal nuclear grooves were studied and examined for clinicopathologic characteristics.

RESULTS.—

The lesions occurred in 16 women and 2 men aged 36 to 88 years and measured from 0.2 to 1.5 cm. The tumors were well circumscribed and noninvasive, and histologically characterized by a predominantly solid growth pattern with rare scattered follicles or a combination of solid growth pattern with minor follicular areas. A striking feature seen in all cases was the occurrence of longitudinal nuclear grooves. Immunohistochemical stains showed negativity for cytokeratin 19 (CK19) and HBME-1 in 8 cases; in the other 10, there was focal positivity for HBME-1 in 4 cases and diffuse positivity in 6. All cases were negative for galectin-3 and for CK19, with the exception of 1 case, which was CK19+/HBME-1-. Next-generation sequencing of 16 cases with a 161-gene panel detected 14 single nucleotide variants in 12 cases, predominantly NRAS and HRAS mutations. Clinical follow-up ranging from 18 to 72 months (median, 43.7 months) did not disclose any evidence of recurrence or metastases.

CONCLUSIONS.—

We interpret these lesions as low-grade, indolent follicular proliferations that need to be distinguished from papillary thyroid carcinoma, follicular adenoma, and noninvasive follicular thyroid neoplasms with papillary-like nuclear features.

Is an indistinct picture "exactly what we need"? Objectivity, accuracy, and harm in imaging for cancer

Assumptions about the epistemic ideal of objectivity, closely related to ontological assumptions about the nature of disease as pathophysiological abnormality, lead us into oversimplified ways of thinking about medical imaging. This is illustrated by current controversies in the early detection of cancer. Improvements in the technical quality of imaging failed to address the problem of overdiagnosis in breast cancer screening and exacerbate the problem in thyroid cancer diagnosis. Drawing on Douglas and on Daston and Galison, I distinguish 3 dimensions of objectivity (accuracy, reliability, and precision) and demonstrate ways they may be at odds, as illustrated in the early detection of cancer. Guidelines for evaluating the efficacy of diagnostic imaging are insufficiently sensitive to this complexity. Improving imaging quality may raise epistemic issues, place disease definitions in question, and lead to overall harm or to changes in the distribution of harms and benefits among population subgroups. With a nod to Wittgenstein, I argue that we cannot take for granted that "an indistinct picture" is not "exactly what we need."