Case 1
Clinical features :
Female patient, 32 years old. Euthyroid nodule, slowly growing since 7 months
Gross features :
Right, well circumscribed, 3,5 nodule, with fleshy appearance
| Microscopy : |
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| Pure follicular proliferation of medium to large size
follicles with irregular shape, rigid borders, sometimes elongated (tubular). Colloid has
a strong eosinophilic appearance with scalloped borders (fig B) |
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fig. B |
| Folliculars cells have clear cytoplasm and exibit constant
nuclear characteristics of papillary carcinomas (fig C) : large size, ground glass and overlapping ; nuclear
irregularities in contours with indentation,folds and grooves. |
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fig. C |
In some nuclei, a prominent nucleolus has been pushed against
the nuclear membrane.
Mitotic figures are very rare or absent.
The stroma is rare without psammomaa bodies.
This lesion is surrounded by a thick fibrous capsule, irregular (fig A). |
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fig. A |
Diagnosis :
Papillary carcinoma pure follicular variant, encapsulated, intra-thyroid, p T2 stage
Comments :
In this case, the differential diagnosis is with an atypical adenoma : however, in
this encapsulated tumor, the diagnosis can be ascertained by an unique sign : nuclear
features of papillary carcinoma. Those characteristics are more significant for the
diagnosis than papillae.
A follicular carcinoma, encapsulated variant can be ruled out because nuclear features.
When the nuclear features are less typical, one can be helped by positive immunostaining
with HBME1 antibody which is positive in case of papillary carcinoma, negative in atypical
adenoma (but not in all cases).
This tumor has many features of favorable pronostic :low pathologic stage, size under 4
cm, and almost encapsulated form. Encapsulated variant of papillary carcinoma represents
about 10 % of cases and the rate of lymph node metastasis is very low.
References :
BERGER N., BORDA A., BIZOLLON MH.
Le carcinome papillaire de la thyroïde et ses variantes.
Arch. Anat. Cytol. Path, 1998, 46, 45-61
CARCANGIU ML., ZAMPI G.
Papillary carcinoma of the thyroid.
Cancer - 1985 - vol. 55 - p. 805-828.
EVANS HL.
Encapsulated papillary neoplasms of the thyroid.
Am. J. Surg. Pathol. - 1987 - vol. 11 - p. 592-597.
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