Diapositiva 1
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Transcript Diapositiva 1
SOLITARY METASTASIS OF RENAL CLEAR CELL
CARCINOMA TO HÜRTHLE CELL ADENOMA OF
THYROID GLAND: REPORT OF A CASE
RITA PASSANTINO - LORENZO MARASA’
Department of Pathology, A.R.N.A.S. Civico, Palermo
INTRODUCTION
Metastases to the thyroid gland are a common finding at
autopsy in patients who died of malignancy and are
often misdiagnosed as primary thyroid neoplasms
clinically.
Metastatic Renal Cell Carcinoma (RCC) to the thyroid
gland is a rare occurence but must be considered in the
differential diagnosis of Clear Cell Tumours (CCT) of the
thyroid gland to prevent misclassification, potentially
resulting in inappropriate clinical management.
We present a patient with a rare, unusual case of RCC
metastatic to a Hürthle cell adenoma of the thyroid
gland.
CASE REPORT
The patient was a 77-year-old sicilian woman who was
referred to our department after a thyroid tumour was
identified in February 2008.
She had a history of RCC of the left kidney, which had
been resected 3 years previously.
Ultrasound
sonography
demonstrated
a
welldemarcated hypoechoic mass which measured 3.5 cm
in greatest diameter and occupied the left lobe.
A total thyroidectomy was performed on March 2008.
A solitary, well circumscribed, encapsulated, bright
yellow to reddish-tan mass with hemorrhage and
degenerative changes, which measured 3.5 cm in
greatest diameter and occupied the left lobe of the
thyroid gland.
HISTOLOGICAL EXAMINATION
A Hürthle cell adenoma containing large clusters of
cells with abundant clear cytoplasm and round
nuclei.
The
predominant
histologic
pattern
was
characterized by the presence of small nests, cords
and “pseudofollicles” made up of neoplastic cells
separated by a prominent vascular stroma with
sinusoidal-type blood vessels and intraluminal fresh
hemorrhage.
Metastatic cells contained variable amounts of PASpositive material which was indicative of glycogen in
the cytoplasm of the clear cells.
Metastasis showed morphological characteristics
identical to the RCC resected 3 years previously.
IMMUNOHISTOCHEMICAL EXAMINATION
Specific markers of Hürthle cell adenoma such as
thyroglobulin, CK14, CEA, S-100 protein and HMB-45
stained negatively in the clear neoplastic cells.
Specific markers of RCC such as EMA and vimentin
stained positively.
THYROGLOBULIN
EMA
VIMENTIN
CONCLUSIONS
The thyroid gland is a rare site of tumour metastasis.
RCC is one of the more common neoplasm to
metastasize to the thyroid gland (<0.1%).
Metastatic RCC to a thyroid neoplasm is extremely rare,
with only three reports found in the international
literature.
The possibility of metastatic RCC should always be
taken under consideration, especially when nests of
clear cells are seen infiltrating into the thyroid
parenchyma or neoplasm.
CONCLUSIONS
Our report shows that the architectural, cytologic, histologic, histochemical, and immunohistochemical features are sufficiently distinctive to allow differentation
of a primary thyroid epithelial neoplasm with clear cell
changes from metastatic RCC.
This distinction is important to correctly manage the
patient.
Surgical treatment is recommended as the patient may
enjoy a prolonged survival.
MAIN REFERENCE:
Qian L. Renal cell carcinoma metastatic to Hürthle cell
adenoma of thyroid. Ann Diagn Pathol. 2004 Oct; 8(5):
305-8.