Case 4
Clinical features :
Female patient, 54 years old. Euthyroid nodule since 12 years. FNA : atypical
follicular lesion
Gross features :
Left, 4,6 cm, solitary nodule, tan-brown and fleshy appearance. The capsule is
pearly, thick, irregular, with cacifications.
| Microscopy : |
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| Hypercellular follicular proliferation of medium size
elements (fig A) filled
with abundant colloid. |
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fig. A |
| The cells have a large nucleus, with quite prominent
nucleolus (fig B), without
any characteristics of papillary carcinoma. In some areas, there is mitosis. |
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fig. B |
| This lesion is surrounded by a thick fibrous capsule which
shows frequent protrusions of tumor cells within the fibers (fig C), and obvious vascular
invasion (fig D). |
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fig. C |
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fig. D |
Diagnosis :
Follicular thyroid carcinoma, minimally invasive, intra-thyroid, p T3
Comments :
The diagnosis of follicular carcinoma is only established by demonstration of
capsular and/or vascular invasion which must be searched by multiple sections especially
if this capsule is thick. For capsular invasion, irregularities of contours along the
inner borders are not sufficient, while mushroom-like expansion is characteristic of
invasion into and through the entire capsule.
Vascular invasion is a more reliable sign of malignancy. The vessels should be located
within the capsule, it should be of large caliber and have an identifiable wall of
endothelial lining. The intravascular cells should project into the vessel lumen and must
be attached at some point to the vessel wall.
Follicular carcinomas can be divided into 2 major categories on the basis of the degree of
invasiveness : minimally invasive or encapsulated and widely invasive.
The prognosis of minimally invasive is excellent perhaps as good or better as that of
papillary carcinoma.
For Lang, widely invasive carcinomas are more often associated with blood borne metastasis
(80%) and the death /rate is about 20%.
References :
CARCANGIU ML
Minimally invasive follicular carcinoma.
Endocrine Pathology, 1997, 8, 231-234.
FRANSILLA K.O., ACKERMAN L.V., BROWN C.L., HEDINGER C.E.
Follicular carcinoma.
Semin Diagn Pathol. 1985 ; 2 : 101-122.
LANG W., CHORITZ H., HUNDESHAGEN H.
Risk factors in follicular thyroid carcinomas.
Am J. Surg. Pathol. - 1984 - vol. 10 - p. 246-255.
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