269 / 366
8
–
84 age range). The body of the mandible was the commonest
site (
n
= 131), followed by the maxilla (
n
= 54, mostly in the
alveolar process region).
Conclusion:
Diagnosis of jaw cysts requires the integration of clinical
and pathological findings. This study showed that the majority of the
odontogenic cystic mass of the jaws are inflammatory.
PS-23-001
Immunohistochemical analysis of a series of rhabdomyosarcomas
diagnosed at a Tertiary Cancer Referral Centre
C. Gupta
*
, B. Rekhi, S. Qureshi, G. Chinnaswamy, T. Vora, J. Bajpai, N.
Khanna, S. Laskar
*
Tata Memorial Hospital, Pathology, Mumbai, India
Objective:
To evaluate immunohistochemical features of a series of 300
rhabdomyosarcomas (RMSs).
Method:
Immunohistochemical expression of myogenin and MyoD1
was graded, based on percentage of tumour cells displaying positive
intranuclear immunostaining, namely grade 1 (1
–
25 %); grade 2 (26
–
50 %); grade 3 (51
–
76 %) and grade 4 (76
–
100 %).Outcomes/ follow-
up details were available in 272 (90.7 %) patients. High myoD1 and
myogenin immunoexpression (in more than, equal to 51 % tumour cell
nuclei) were correlated with various subtypes.
Results:
There were 140cases (46.7 %) of alveolar RMS(ARMS),
90 of embryonal RMS(30 %), 61(20.3 %) of spindle cell/ scle-
r o s i ng RMS a n d 9 c a s e s ( 3 %) o f p l e omo r ph i c RMS .
Immunohistochemically, desmin was expressed in 292/
299(97.6 %) tumours, myogenin in 238/267(89.1 %), MyoD1 in
192/266(72.2 %), synaptophysin in 17/71(23.9 %), S100 protein
in 11/75(11.5 %), WT1 in 18/29(62 %) and variable MIC2/CD99
in 61/148(41.2 %) tumours. High myogenin expression was sig-
nificantly associated with cases of ARMSs (95/121,78.5 %), com-
pared to other subtypes(48/117, 41 %)(
p
< 0.001). High MyoD1
expression was seen in more cases of pure sclerosing and spindle
cell/ sclerosing RMSs (10/10, 100 %), compared to the other
subtypes (91/141, 67.4 %)(
p
= 0.032).
Conclusion:
This study reinforces significant association between
high myogenin expression and cases of ARMS, as compared to
other subtypes. High MyoD1 expression was seen more in cases
of spindle cell/sclerosing RMSs. Certain RMSs, especially ARMS
also display neuroendocrine differentiation.
PS-23-002
Desmoid type fibromatosis: Clinicopathologic analysis of 113 cases
E. Buyuktalanci
*
, B. Yaman, T. Akalin
*
Ege University, Pathology, Izmir, Turkey
Objective:
Recurrence relation with surgical margin status, tumour loca-
tion and patient age were evaluated in desmoid type fibromatosis with
current follow-up.
Method:
Patients diagnosed as desmoid type fibromatosis between 2000
and 2016 were evaluated.
Results:
Of these 113 cases, 42 were male and 71 were female, median
age was 33 ± 18 (4
–
95). Twenty two (19 %) of them were younger than
17 years old. Of these cases 74 (66 %) were extraabdominal, 24 (21 %)
were abdominal and 15 (13 %) were intraabdominal. Extraabdominal
tumours were mostly located at lower extremity (%47). Of the 54
follow-up known cases, recurrence occurred in 18 cases (33 %). Of these
18 cases, 6 were younger than 17 years old. Of these 18 cases
extraabdominal, abdominal and intraabdominal locations were 16, 1
and 1 respectively and the relation between tumour location and recur-
rence was significant (
p
= 0,031) . Of the 90 cases whose surgical margin
was evaluated, 81 % were positive. Significant correlation was found
between surgical margin status and recurrence (
p
= 0,023). There was
no recurrence in 16 cases whose the surgical margins were positive (me-
dian follow up 59 months). Sixty four tumour were studied
immunohistochemically with Beta catenin and nuclear positivitiy was
seen in 53 tumour (83 %).
Conclusion:
Desmoid type fibromatosis is a locally agressive tumour.
Extraabdominal location and positive surgical margin status are risk fac-
tors for recurrence. Some tumours may stable for some years though
margin positivity.
PS-23-003
Review of pleomorphic liposarcomas in La Paz Hospital
D. Roldán
*
, Y. Brygadyr, D. Fuel Gómez, A. Berjón García, J. J. Pozo
Kreilinger
*
Hospital Universitario La Paz, Madrid, Spain
Objective:
Our aim was to review all the pleomorphic liposarcomas and
dedifferentiated liposarcomas with pleomorphic components (considered
separately due to differences in prognosis) diagnosed in La Paz In the
period 1965
–
2017.
Method:
We searched our database for all liposarcomas and selected the
pleomorphic liposarcomas and dedifferentiated liposarcomas with pleo-
morphic features diagnosed in our centre and retrieved clinical data about
sex, age and location.
Results:
Among the 291 liposarcomas diagnosed in our centre we found
20 cases of pleomorphic liposarcoma and dedifferentiated liposarcoma
with a pleomorphic component. The mean age was 58 years (range 32
–
88) and the distribution was similar among sexes (55%F/45%M). The
most common location was the leg (60 %), followed by the
retroperitoneum (10 %) and the chest wall (10 %). Most of the tumours
were predominantly composed of a high grade sarcoma (pleomorphic
undifferentiated sarcoma-like), with the diagnostic pleomorphic
lipoblasts being a minoritary component.
Conclusion:
Pleomorphic liposarcoma is a rare entity, and the most un-
common subtype of liposarcoma. We submit the experience from our
centre for over more than 50 years in order to help to define and under-
stand better this infrequent tumour. The scarcity of the diagnostic areas
emphasizes the necessity of an extensive sampling in order to avoid
underdiagnosing.
PS-23-004
Case report: Secondary osteosarcoma arising in the femur of a 26-
year-old woman with a long-standing benign orthopaedic condition
O.-M. Andreoiu
*
, D. M. Pop
*
Emergency University Hospital, Dept. of Pathology, Bucharest,
Romania
Objective:
Osteosarcoma arising in association with metallic ortho-
paedic devices(DCS) in benign conditions (symple bone cyst-
SBC) is rare, understudied and has unknown mechanisms. Our
pacient known with SBC had multiple surgical orthopaedic inter-
ventions for complications (infection, fracture) and ultimately de-
veloped an osteosarcoma.
Method:
We present a case of a 26-year-old woman with a long history of
disease. Thirteen years ago the patient suffered a pathologic fracture of
the right femoral neck due to SBC, underwent orthopaedic reduction and
plaster cast immobilization, healed with secondary coxa vara, limb short-
ening and difficulty walking. In 2010, was admitted for open curettage
Wednesday, 6 September 2017, 09:30
–
10:30, Hall 3
PS-23 Soft Tissue and Bone Pathology
Virchows Arch
(
2017
)
471
(
Suppl 1
):
S1
–
S352
S255