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Squamous metaplasia in a multinodular goiter: a case
report.Indian
J Pathol Microbiol. 2003 Jan;46(1):100-1.
Squamous
epithelium in thyroid is an unusual finding. It is seen in a variety
of inflammatory and neoplastic conditions. It's presence has been
attributed to metaplastic change of follicular epithelium by some
authors and to the persistence of ultimobranchial body by others. We
encountered a case of multinodular goiter with groups of squamous
cells lining a cystic cavity. We report it because of it's rarity with
a brief review of literature.
Extensive
squamous metaplasia in nodular goiter--a diagnostic dilemma in the
fine needle aspiration (FNA) cytology--a case report.
Indian J
Pathol Microbiol. 2002 Jan;45(1):111-3.
Metaplastic
changes are commonly found at widespread locations occurring in both
reactive and neoplastic conditions. They can simulate tumors
histologically. Squamous metaplasia is rarely seen in areas of
fibrosis and inflammation secondary to hemorrhage in nodular goiters.
If it is extensive with associated degenerative changes and present
clinically in the form of a nodule, cytopathologist must take care to
differentiate this from primary or metastatic squamous cell carcinoma
or even anaplastic carcinoma.
Squamous cells
in the human thyroid gland.Am
J Surg Pathol. 1978 Jun;2(2):133-40.
Squamous
epithelium in the thyroid, which may be basaloid, epidermoid, or truly
squamous, may be derived from several sources. In the normal thyroid,
usually rests of one type or another are responsible for these cell
nests. Thus, thymic or ultimobranchial remanants may be found in the
lateral lobes of normal thyroid glands. Maldevelopment or excessive
descent of thyro-glossal duct remnants may be responsible for squamous
epithelial cysts noted in the central portions of the thymus,
especially in the isthmus. In diseased thyroids, the most likely
derivation of squamous or epidermoid epithelium is through metaplasia
of follicular epithelial cells. Thus, in adenomatous goiter and
various types of thyroiditis as well as follicular derived neoplasms,
such a derivation is most likely. In tumors containing malignant
squamous epithelium (adenoacanthoma, adenosquamous carcinoma, or pure
squamous carcinoma) there is a range of such lesions, and since many
of them appear to be derived from follicular epithelium, it is most
likely that squamous metaplasia which has undergone malignant
transformation has occurred in these neoplasms.
Cystic goiter with squamous-cell metaplasia--case
report and comment on origin of squamous-cell cyst.
Acta Pathol
Jpn. 1976 Jul;26(4):503-8.
A 53-year-old
woman with a left unilocular cystic goiter of the size of a small
orange was reported. Approximately four-tenths of the innter surface
was lined with several layered squamous epithelium with few follicles
remaining. A gradual metaplastic transition from the follicular
epithelium to the flattened cuboidal and to the squamous epithelium
was observed. The ultimobranchial body has been understood to be a
possible origin of an entirely squamous cell cyst of the thyroid,
three of which have been reported. The difference between the ultimo-branchial
and metaplastic origins will be discussed, and a new
designation-primary (ultimo-branchial) and secondary (metaplastic)
squamous-cell cyst will be proposed.
Massive
squamous metaplasia of the thyroid gland-- report of three cases.Pathol
Res Pract. 2006;202(2):99-106.
Three cases of
massive squamous cell metaplasia in Hashimoto's thyroiditis are
reported. The patients were two men and one woman aged 24, 52, and 55
years, respectively. In all three patients, the glandular parenchyma
was replaced by hypocellular fibrous tissue with scattered chronic
inflammatory infiltrate. Follicular cells were almost absent; the
majority of residual epithelial cells formed squamous nests that were
partly solid and partly cystic. There were three types of epithelial
cells - squamous, basaloid, and follicular, with oncocytic
differentiation. The squamous and basaloid cells showed strong
positivity high molecular weight (HMW) cytokeratin, moderate to strong
expression of galectin-3 (2/3), and nuclear expression of p63 protein
(2/3). The staining pattern of p63 was identical to that of HMW, with
predominant positivity at the periphery of cell nests. In one case,
weak but unequivocal positivity of thyroid transcription factor-1 also
was present. We believe that metaplasia was caused by Hashimoto's
thyroiditis. The cases presented here are extremely rare, and only two
convincing similar cases have been reported in the English literature
so far. They may represent a diagnostic pitfall and should not be
misdiagnosed as a malignancy, in particular as squamous cell or
mucoepidermoid carcinoma.
Squamous epithelium in the human thyroid gland.J
Clin Pathol. 1966 Jul;19(4):384-8.
Four cases are
reported in each of which squamous epithelium was an incidental
finding in surgically excised thyroid gland tissue. The occasional
thyroid cyst lined throughout by squamous cells probably represents a
persistent ultimo-branchial body, but the evidence indicates that the
usual source of such cells in this gland is metaplasia of the
follicular epithelium. An explanation is offered for the infrequency
of this transformation in the thyroid, despite the frequent occurrence
of the changes which predispose to epithelial metaplasia at other
sites. There is no evidence to suggest that squamous cells arising in
this gland by either of these means have any sinister significance.
Unusual non-neoplastic lesions in the "surgical
pathology" of the thyroid.Pathologica.
2006 Apr;98(2):119-38.
This review aims
to describe and assist in the categorization of most of the unusual
non-neoplastic conditions, encountered in the surgical pathology of
the thyroid. The conditions included are: normal intrathyroidal
vestigial tissues/structures (i.e. rests of the ultimobranchial body
and thyroglossal duct) and their relevant pathological derivatives (ultimobranchial
body cyst, intrathyroidal lymphoepithelial cyst, thyroglossal duct
cyst); mature intrathyroidal heterologous tissues/organs of either
metaplastic or heterotopic origin (adipose tissue, striated skeletal
muscle, cartilage, parathyroid glands, thymus, salivary gland tissue)
and their relevant pseudotumoural lesions; varieties of metaplastic
and non-metaplastic morphologic changes of the thyroid follicular
epithelium (oncocytic, clear cell/signet ring cell, darkly pigmented
cell, mucinous (myxoid), squamous, spindle cell); amyloid goiter; some
reactive and/or degenerative cytologic and nuclear atypicalities
(nuclear pseudoclearing and cell pleomorphism) as well as some
hyperplastic or peculiar growth patterns (capsular pseudoinvasion;
vascular invasion; papillary carcinoma-like and paraganglioma-like
patterns) of benign conditions mimicking neoplasia; and finally. some
pseudotumoural lesions of the stroma (pseudoangiosarcomatous vascular
proliferation, and post-fine-needle aspiration spindle cell nodule).
The pathogenetic mechanism, the morphologic interpretation, and the
differential diagnosis of each of the above-listed conditions are
discussed and pertinent illustrations for many of them are also
provided. Lesions of thyroid tissue situated outside of the gland
itself are not discussed.
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