Download 每月一例 2015 December

每月一例 2015 December
• A 32-year-old woman was healthy and denied
any systemic disease.
• Multiple thyroid nodules were found incidentally
during a routine healthy check. Ultrasound
examination revealed multiple nodules in both
lobes of the thyroid, with a hypoechoic one, 0.8
cm, in the left lobe.
• Thyroid function was within normal limits. No
other lesions were identified in the head and
neck area.
Clinical presentation
• Fine needle aspiration of the nodule was performed and
the aspirate was submitted to the cytology laboratory as
one ethanol-fixed smear for Papanicolaou stain, one airdried smear for Liu’s stain, and one SurePath BD
CytoRichTM vial for liquid-based preparation (Becton,
Dickinson and Company).
Your interpretation ?
PTC ?
Variant ?
Cytology findings
• The smears showed moderate cellularity in a clean
background devoid of colloid and blood. It consisted of
loosely cohesive three-dimensional and mono-layer
clusters of cells.
• Occasional papillary fragments with vascular cores were
present.
• Pseudostratified epithelium composed of cigar-shaped,
elongated hyperchromatic nuclei in a picket-fence-like
arrangement was apparent.
• Nuclear grooves and intranuclear pseudoinclusions were
found in very limited area.
Diagnosis
Papillary thyroid carcinoma (PTC),
columnar cell variant
Differential diagnosis
• Papillary thyroid carcinoma, tall cell variant
• Metastatic endometrioid or colorectal
adenocarcinoma
• Upper respiratory epithelial cells contamination
from the aspiration procedure
DDx: Papillary thyroid carcinoma,
tall cell variant
• The criteria of tall cell variant PTC was recently lowered
to over 50% of cancer cells with 2-3:1 height/width ratio.
• The nuclei frequently have the characteristic classic PTC
features showing oval and optically clear nuclei with
nuclear grooves and pseudoinclusions.
• Therefore, it is easy to be interpreted as a PTC.
• However, you will find loosely cohesive clusters of cells
with rows or parallel cords of tall cells, which raises the
possibility of the tall cell variant.
Columnar cell vs Tall cell variant
• On the contrary, the characteristic PTC nuclear features
are not apparent in the columnar cell variant.
• Although both subtypes will have tall or columnar cell
features, the differential is not very difficult.
DDX: Metastatic endometrioid or colorectal
adenocarcinoma
• The elongated overlapping and stratified nuclei with
occasional supranuclear and/or subnuclear cytoplasmic
vacuoles of columnar cell variant PTC will resemble
those of metastatic endometrioid or colorectal
adenocarcinoma.
• However, these cancers seldom metastasize to the
thyroid. If it is a metastatic lesion in the thyroid, usually it
will happen in an advanced stage of disease. So, the
differential diagnosis could be easily made by the clinical
presentation and history.
DDX: Metastatic endometrioid or colorectal
adenocarcinoma
• The immunocytochemical stains for ER and CDX2 are
not useful; because they have been found to be positive
in up to two thirds and 55% of columnar cell variant PTC,
respectively.
DDx: Upper respiratory epithelial cells
contamination from the aspiration procedure
• The pseudostratification pattern of columnar cell variant
PTC may show a resemblance to the upper respiratory
epithelial cells which are sometimes inadvertently
aspirated during the thyroid aspiration procedure.
• However, no cilia could be identified in any of these
cells.
• In addition, the presence of vague PTC nuclear features
or background colloid material would help a lot in the
differential diagnosis
Discussion & Conclusions
• Columnar cell variant PTC is a rare thyroid cancer
(accounting for 0.2% of PTC) and characterized by
columnar cells with hyperchromatic elongated nuclei in
pseudostratified arrangement.
• The classic nuclear features of conventional PTC are not
frequent.
• The differential diagnoses, including tall cell variant PTC,
metastatic endometrioid or colorectal cancers, and
contaminated respiratory epithelial cells, are not
problematic after consideration of clinical presentation,
past history, and overall cytomorphology.
Discussion & Conclusions
• Columnar cell variant was previously thought to be more
aggressive than conventional PTC. However, recent
studies showed that the behavior was more related to
tumor size and extra-thyroid involvement rather than
histologic subtype per se.
• Better prognosis was found in small sized circumscribed
or encapsulated tumor in younger female patients.
• The V600E BRAF mutation was identified in
approximately one third of this variant, which is similar to
that in conventional PTC.
• More studies are needed for further evaluation of the
prognosis and behavior of this tumor in the future.