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Sonography of thyroid
 Left lobe : Heterogenous
mix echo lesion 15*13 mm
 Isthmus : mixed echo lesion 8*12 mm
 Right lobe : normal
Papillary carcinoma
•Follicular
•Tall cell
•Clear cell
poorly differentiated carcinoma
Squamous cell carcinoma???!!!
papillary cell carcinoma
 Areas with a solid/trabecular pattern of growth are
present in 20% of the papillary carcinoma and foci of
squamous metaplasia in a similar number .the
presence of such foci is not per se an indication that
the tumor is poorly differentiated unless accompanied
by other alteration
 Poorly differentiated squamous or anaplastic foci
have a markedly detrimental effect on prognosis.
Fortunately, they are present in fewer than
5% of the cases.
Squamous cell carcinoma
Squamous cells can be found in the thyroid as' a result of
persistence of thyroglossal duct or structures derived
from the branchial pouch (such as thymic epithelium) or
as an expression of squamous metaplasia in Hashimoto's
thyroiditis, papillary carcinoma, or other conditions.
Pure squamous cell carcinomas are exceptional.
Squamous cell carcinoma
Most high-grade thyroid tumors with squamous foci
blend with areas of undifferentiated (anaplastic)
carcinoma and are generally placed in the
latter category because of their similar natural history.
Indeed, many of them are seen to develop from papillary
carcinoma in a fashion analogous to that of
undifferentiated carcinoma.
has been suggested that the tall cell variant of papillary
carcinoma has a particular tendency to evolve into the
spindle cell type of squamous cell carcinoma.
Squamous cell carcinoma
Another rare entity occurring in or around the thyroid
that may exhibit squamous differentiation is the
malignant neoplasm we have chosen to designate as
carcinoma showing thymus-like differentiation
(CASTLE).
This tumor (of which a cystic variant has been
described) could be viewed as an ectopic thymic
carcinoma
Squamous metaplasia in papillary
carcinoma
Or
Branchial puoch(thymus)=CASTLE
Support for the thymic rather than thyroidal origin of
CASTLE is provided by its immunoreactivity for
CD5
CD117
HMWK
P63
BCL-2
mcl-1
all of them being markers associated with
thymic carcinoma) and negativity for TG and TTF-1.
Immunohistochemically, the cells of papillary carcinoma
are reactive for
pan-keratin CK7 + / CK20CK19
HMWK*
thyroglobulin and TTF-1 is the rule
CEA*
CA-125
Carcinoma showing thymus-like differentiation (CASTLE) is
a rare intrathyroidal neoplasm, a member of a tumor family
probably arising from ectopic thymus or branchial pouch
remnants. Thyroid solid cell nests (SCNs) may also be
derived from branchial pouch remnants. In normal
thyroid, only SCNs stained for p63, HMWK, and CEA. The
only CD5-positive cells in normal thyroid were T cells. All
CASTLE exhibited diffuse p63 and HMWK staining and
were positive for CEA and CD5. In contrast, none of the
other thyroid neoplasms exhibited consistent staining for
all 4 markers studied. These findings provide further
evidence that CASTLE is distinct from other thyroid
neoplasms, is probably of thymic origin, and may arise
from branchial pouch remnants, the thyroid SCNs.
Moreover CD5, HMWK, CEA and p63 can be used to help
distinguish CASTLE from other thyroid neoplasms.
We present the case of a 62-year-old woman who
consulted her physician in December 2009, suffering
from a mass at the left lower anterior neck with rapid
enlargement. Intraoperative frozen section was highly
suspicious of a CASTLE tumour (carcinomas showing
thymus-like differentiation). Finally,
immunohistochemical investigation revealing
positivity for CK5/6, c-kit (CD117) and CD5 as well as
negativity for thyroglobulin, calcitonin, vimentin and
TTF-1 confirmed the diagnosis.
Papillary:
Squamous:
 TTF-1 : +
 TTF-1 : -
 TG : +
 TG : -
 CD5 : -
 CD5 : +
Papillary carcinoma
CASTLE :‫عنوان‬