Sabato 27 ottobre 2012 - Pacini Editore

PoStER
believed the use of atypical adenoma should be discouraged. P53
is a well characterized tumour suppressor gene. This gene encodes
for a nuclear phosphoprotein which is important in the regulation
of the cell cycle. Mutations of the p53 tumor-suppressor gene represent
the most common genetic alteration in human tumours. The
products of this gene is a nuclear protein thought to be involved
in the control of the cell cycle, apoptosis, and the maintenance
of genomic stability. The altered protein product of the mutant
gene has a much extended half-life and can be detected with immunohistochemical
techniques. It should be noted, however, that
accumulation of the protein can also occur as a result of epigenetic
changes, and therefore it is not an obligatory indicator of a gene
mutation. As far as the thyroid gland is concerned, p53 mutation is
frequently detected in anaplastic and poorly differerentiated carcinomas
6-9 . Tzen et al. 10 have analyzed the p53 genes in 2 atypical
adenomas. Mutations of p53 where detected in the bizarre cells
but not in the bland-looking follicular cells. Tzen et al. believed
atypical adenomas showed an identical point mutation in codon
273 (CGT-CAT), a common mutation in various human cancers,
including anaplastic carcinoma of the thyroid. This finding supports
the view of the authors that atypical follicular adenoma is
a precursor of thyroid anaplastic carcinoma and suggests that
“atypical adenoma” should not be used to express diagnostic uncertainty
about the nature of a lesion. Sato et al. 11 have examined
the immunohistochemical expression of p53 protein in the bizarre
nuclei of thyroid adenomatous nodule with micro-and macrofollicular
components, cystic degeneration, a hyalinised region and
papillary structure. The bizarre cells diffusely expressed p53 protein,
but the follicular cells were negative. In the study of sato et
al. no mutation of exons 5-9 of the p53 gene was detected in the
bizarre nuclei. Sato et al. believed that bizarre nuclei can be seen
in benign thyroid lesions and overdiagnosis should be avoided
regardless immunohistochemical overexpression of p53.
The immunohistochemical expression for p53 has been examined
in thyroid adenomas. Kanthan
et al. 12 have examined the p53 expression in twenty five cases of
thyroid adenomas with hurtle cells changes, both pure and focal.
The majority of the Hurtle cells where p53 positive and adenomas
with an increased number of hurtle cells had an a increased percentage
of p53 staining. Othman et al. 13 have studied the p53
protein expression in 52 cases of thyroid follicular adenomas
and have found in 6 case(11.5%). P53 positive. Nasir et al. 14
have studied p53 expression in 20 follicular adenomas and 21
follicular carcinomas of the thyroid. These authors found 90%
of follicular carcinomas exhibited strong nuclear p53 expression.
P53 stain was seen in only 15% of follicular adenomas. These
authors believed that immunohistochemical detection of p53 with
others markers(CD44V6 and CD57) may have practical utility
differential diagnosis of follicular carcinoma from follicular carcinomas
from follicular adenomas in routine surgical pathology.
Hosal et al. 15 also reported weak p53 positivity using immunohistochemistry
in 1 out of 6 (16,66%) follicular adenoma while
the positivity was diffuse and strong in all five anaplastic carcinomas
examined. The present case is the fast report of coesistence
variant follicular of papillary carcinoma, atypical adenoma and
adenoma with nuclei bizarre in the same thyroid. The diffuse
expression of p53 in the bizarre, atypical cells of the adenomas is
of difficult interpretation. Further studies has been necessary and
critical review was made regarding the of the utility of immunohistochemical
detention in the differential diagnosis of follicular
adenomas from follicular carcinomas.
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GASTrOEnTErICO
Incidental well differentiated papillary mesothelioma
of the omentum in a male patient: a case report
L. Abete, E. Pacella, B. Bocca, T. Celiento, F. Sarocchi, A. Guadagno,
F. Grillo, L. Mastracci
Histopathology, DISC, University of Genova - IRCCS Azienda Ospedaliera
Universitaria San Martino, IST, Istituto Nazionale per la Ricerca
sul Cancro
Introduction. Well-differentiated papillary mesothelioma
(WDPM) is a rare tumor most frequently observed in women
of reproductive age. It involves most commonly the peritoneum
although it is rarely seen in other anatomic sites. This neoplasm is
considered a tumor of uncertain malignant potential although information
about its biological behavior is still limited. We report
a rare case of a WDPM in an elderly man.
Methods and materials. A 70 year old male with a prior recent
history of complicated inguinal hernia presented to hospital with
right upper quadrant pain consistent with biliary colic. An abdominal
ultrasound scan demonstrated multiple small echogenic
foci in the lumen of the gallbladder suggestive of calculi. He
underwent an elective laparoscopic cholecystectomy for cholelithiasis.
During laparoscopic inspection, an unexpected incidental
lesion located to the omental tissue was noted. It consisted in a
well-demarcated, rough, whitish ovalar plaque-like proliferation
on the serosal surface of the omentum measuring 5x4 cm (Fig. 1).
Moreover, in the abdominal cavity a peritoneal pseudonodule
containing a Prolene hernioplastic implant and an infarcted epiploic
appendix were also observed.
Results. Along with the gallbladder, the omental lesion, the
infarcted epiploic appendix and the nodular lesion with the entrapped
Prolene implant were submitted to our Institution for
pathological examination. The gallbladder grossly measured
8 cm in length, and several small luminal calculi were found