Cytologicky benigní folikulární léze

Cytologické diagnostické znaky

  • nízká nebo st?ední bun??nost
  • kohezivní bu?ky
  • p?evážn? mikrofolikulární úprava
  • uniformní, pravideln? uložené folikulární bu?ky
  • okrouhlá jádra, jemn? granulární chromatin
  • chudá nebo st?ední cytoplazma
  • málo makrofág?
  • nahá jádra

Koloid je obvykle hojný v podob? amorfních kapek nebo jako tenký pr?svitný film s bublinami a lineárními trhlinami.

N?které benigní folikulární léze jsou hypercelulární a mohou dokonce obsahovat fokální cytologické atypie. P?íležitostné se mohou objevit velké v?etenité bu?ky reprezentující bu? reaktivní stromální elementy nebo zm?n?né folikulární bu?ky vystýlající cystické dutiny. Fokální onkocytární transformace (Hürthleho bu?ky)  se rovn?ž mohou objevit.  Pokud je mikrofolikl? málo a atypie je fokální , m?la by diagnóza být benigní folikulární uzel i když je zrovna bun??nost vzorku vyšší.

A microbiopsy from a nodular goitre. A thick fragment in which round 3D follicles are separated by collagenous stroma. Orangiophilic colloid is visible inside some follicles whose contours are round. Where thinner a monolayer arrangement can be identified. 
Bland thyrocytes in a microfollicular arrangement. A monolayered sheet of bland thyrocytes with bland chromatin and moderate amount of pale, delicate cytoplasm. In the upper corner a follicle lined by similar cells is observed.  
Bare nuclei and microfollicles. Few microfollicles lined by uniform cells with delicate cytoplasm, round nuclei with fine chromatin and surrounded by bare nuclei (MGG).
A very low power view of a cellular lesion. A very lower power view of a MGG stained smear from a follicular lesion. It is very cellular, colloid is not visible and the cells are arranged in sheets, follicles or lie singly. At this magnification no commitment can be made as whether it is benign, suspicious or malignant. 
At high power the cells are uniform. A microfollicular pattern of regular, uniform thyroid cells exhibiting some "flaring" at their surface, usually seen in functioning cells; they are also monolayered and no reowding is observed.
A trabecular arrangement. The same cells may exhibit a trabecular arrangement; in this case the minimal degree of anisonucleosis is well within normal limits. Anisonucleosis (variability in the volume but not the shape of nuclei) is of very little significance in all endocrine glands and is certainly not a criteria for malignancy (MGG).
Bland, less cohesive thyrocytes. Nuclear detail is better seen in Papanicolaou stain: chromatin is fine and small chromocentres can be seen. Nuclear membrane is regular and thin while cytoplasm is delicate and transparent.
A cellular aspirate at low power. A medium power view of a microfollicular adenoma (MGG). At this magnification lack of background colloid, uniformity of cells and microfollicular pattern are obvious. In the absence of nuclear atypia, crowding or papillary architecture these lesions are classified differently either as follicular lesion, cytologically benign, Thy3 or follicular lesion - indeterminate. In all cases the physician must know that criteria to predict a well differentiated follicular carcinoma are only histological following excision of the lesion to search for capsular or vascular invasion. However an aggressive surgical approach will result in many benign lesions being excised.  
The cells are uniform and arranged in follicles. The same lesion at higher power confirms lack of nuclear atypia and a dominant microfollicular pattern. Bare nuclei are seen in the background, a feature which is reassuring as it is usually associated with benign lesions. 

A microfollicular pattern:

A microfollicular pattern. A microfollicular pattern (MGG); cells appear uniform and no crowding is observed, however few discohesive cells maintain their cytoplasm. 
A stromal fragment with mesenchymal nuclei. At MGG stroma is pinkish and fibrillary with mesenchymal cells appearing as elongated and usually hyperchromatic nuclei; the thyroid cells maintain a follicular architecture and are not arranged perpendicularly to the stroma as expected in a papillary lesion. 
A monolayered sheet of bland thyrocytes. A sheet of monoyared bland thyrocytes surrounded by smaller follicles and bare nuclei. 
A microfollicular arrangement. Bland follicles and bare nuclei. 

Folikulární adenom

Folikulární adenom je benigní nádor- obvykle solitární uzel do pr?m?ru 3cm. N?které mohou produkovat  thyroidální hormony  a vyvolat hyperthyroidismus (funk?ní - horké adenomy). Histologický obraz je variabilní: makrofolikulární (sestává z velkých folikl? vypln?ných koloidem), mikrofolikulární (s malými folikuly), trabekulární s folikulárními bu?kami upravenými do pruh?).

Klasificace (nemá prognostický význam)

  • prostý
  • mikrofolikulární
  • trabekularární
  • oxyfilní
  • atypický
  • papilární
  • z prsténcových bun?k
Nodular hyperplasia Follicular neoplasia
multiple solitary
poorly encapsulated encapsulated
architectural heterogeneity uniformity of the architecture
cytologic heterogeneity cytologic homogeneity
comparable areas in adjacent gland different from surrounding gland
no compression of surrounding gland compression of surrounding gland

Microfollicular groups:

Microfollicular groups - These microfollicles are lined by thyrocytes showing a round nucleus with 'open' chromatin, abundant clear delicate cytoplasm with 'flares'. These findings are in keeping with functioning cells. 
Microfollicular groups - This follicular aggregate shows uniform, bland thyrocytes with delicate, clear cytoplasm but no 'flares'. There is no cytological atypia. A benign follicular lesion may be suggested if the colloid/cells ratio is low and bare nuclei are present in the background. 
Microfollicular adenoma (histology) - A low power view of a histologic section of an adenoma which is clearly separated from the surrounding thyroid tissue (Masson Trichrome stain).
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