Study
of histopathological pattern of soft tissue tumours in tertiary care centre of
Gandhi Nagar, Gujarat
Solanki P.1, Mangar U.2
1Dr. Piyush Solanki, Associate Professor, 2Dr. Urvashi Mangar,
Assistant Professor; both authors are affiliated with Department of Pathology,
GMERS Medical College, Vadnagar, Gujatrat, India.
Corresponding Author: Dr. Urvashi Mangar, 138, Sector-27, Anand Nagar,
Gandhinagar, Gujarat, India. E-mail:
managarurvashi@gmail.com
Abstract
Background: Soft tissue tumours are a diverse and
fascinating group of lesions that arise from the supporting soft tissue of the
body. Although pathologically diverse, they frequently exhibit similar clinical
presentations and radiological features. Correct histopathological diagnosis is
therefore crucial. Aims and objectives: This study aims to analyze the
histopathological patterns of soft tissue tumours and their distribution
according to age, sex and site of occurrence in patients. Methods: This
study comprised of 170 cases of soft tissue tumours received in the Department
of Pathology, GMERS Medical College, Gandhinagar were analysed. Their gross
features, microscopic findings were analysed in detail. Soft tissue tumours
were divided into benign and malignant categories and their further sub typing
were done according to WHO Classification. The distribution of soft tissue tumours
according to the age, sex and site of occurrence was studied. Results: Out
of 170 cases of soft tissue tumours, 158 cases (92.4%) were benign, 2 cases
(1.18%) were malignant and 10 cases (5.88%) were classified under intermediate
category. Adipocytic tumors formed the largest group constituting 92 cases
(46%). Vascular tumors were the second commonest (7%) followed by peripheral
nerve sheath tumours (10.5%). The benign tumours were seen in younger age as
compared to malignant tumours. Conclusion: Benign tumours were more
common than malignant. The most common benign tumours were lipoma followed by
hemangioma (14.0%) and schwannoma (5.5%). There is wide range of their
distribution according to age, sex and site. The benign tumours were seen in
younger age as compared to malignant tumours.
Keywords: Adipocytic,
Histopathology, Malignant, Soft Tissue Tumours.
Author Corrected: 28th December 2018 Accepted for Publication: 31st December 2018
Introduction
Soft
tissue is defined as the complex of non epithelial extra skeletal structures of
the body exclusive of the supportive tissue of the various organs and the
hematopoietic/lymphoid tissue. It is composed of fibrous tissue, adipose
tissue, skeletal muscle, blood and lymph vessels and peripheral nervous system.
Soft tissue tumors are a diverse and fascinating group of lesions that arise
from the supporting soft tissue of the body [1]. Within the various
histogenetic categories, soft tissue tumors are usually divided into benign and
malignant forms [2]. The large majority of soft tissue tumours are benign, with
a very high cure rate after surgical excision. Malignant mesenchymal neoplasms
amount to less than 1% of the overall human burden of malignant tumours but
they are life threatening and may pose a significant diagnostic and therapeutic
challenges Since there are more than 50 histological subtypes of soft tissue
tumours which are often associated with unique clinical, prognostic and therapeutic
features. Immunohistochemistry is used to detect tumor specific alterations
which add significantly to histological interpretation, but several groups of
tumors still lack reliable immuno-histochemical markers [3].
At least one-third of the benign tumours are
lipomas, one-third fibrohistiocytic and fibrous tumours, 10% vascular tumours
and 5% nerve sheath tumours. There is a relation between the type of tumour,
symptoms, location and patient’s age and gender. Lipomas are painless, mostly
occurs in fatty tissue like abdomen, thigh and back. It is rare in hands, lower
legs and foot and very uncommon in children. Multiple (angio) lipomas are
sometimes painful and most common in young men. Angioleiomyomas are often
painful and common in lower leg of middle-aged women, whereas half of the
vascular tumours occur in patients younger than 20 years [4].
Of the benign soft tissue tumours 99% are
superficial and 95% are less than 5 cm in diameter. Soft tissue sarcomas may
occur anywhere but three fourths are located in the extremities (most common in
thigh) and 10 percent each in the trunk wall and retro peritoneum. There is a
slight male predominance. Like almost all other malignancies, soft tissue
sarcomas become more common with increasing age; the median age is 65 years. Of
the extremity and trunk wall tumours one-third are superficial with a median
diameter of 5 cm and two-thirds are deep seated with a median diameter of 9 cm.
Retroperitoneal tumours are often much larger before they become symptomatic. One
tenth of the patients have detectable metastases (most common in the lungs) at
diagnosis of the primary tumour. Overall, at least one-third of the patients
with soft tissue sarcoma die because of tumour metastasis mostly into the lung.
Three fourth of soft tissue sarcomas are histologically classified as high
grade pleomorphic (malignant fibrous histiocytoma [MFH]-like) sarcoma,
liposarcoma, leiomyosarcoma, synovial sarcoma, and malignant peripheral nerve
sheath tumours and three fourth are highly malignant. The age-related
incidences vary; embryonal rhabdomyosarcoma occurs almost exclusively in
children, synovial sarcoma mostly in young adults, whereas pleomorphic high
grade sarcoma, liposarcoma and leiomyosarcoma dominate in the elderly [5].
The two most widely used grading systems are
the NCI (United States National Cancer Institute) system and the FNCLCC (French
Fédération Nationale des Centres de Lutte Contre le Cancer) System. We accessed
the cases received in our department according to FNCLCC grading system [6].
Aims and Objectives
This study aims to analyze the
histopathological patterns of soft tissue tumors and their distribution
according to age, sex and site of occurrence in patients.
Material and Methods
Study Design: The
present study was carried out at histopathology section of pathology department
of GMERS Medical College and General Hospital, Gandhinagar, a tertiary care centrein
Gandhinagar district of Gujarat state, India during the period of March 2013 to
December 2015.
Type of study: Retrospective
Data collection procedure: In
present study, we analysed all 170 cases which received for histopathology
examination under the diagnosis of soft tissue tumours from surgical
department. We also include small biopsies also.
Inclusion criteria: All the mesenchymal tumours arising from any
soft tissue like fibrous tissue, adipose tissue, skeletal muscle, blood and
lymph vessels and peripheral nervous system were included in this study.
Exclusion criteria: All the non-mesenchymal tumors, bone tumors and
any known already diagnosed tumours were excluded from the study.
All
relevant clinical details were obtained from patients or his relatives. Each
received surgical specimen in Histopathology Section were examined grossly for
its size, shape, weight, consistency and appearance. Tissue cut surface was
also examined for the presence of hemorrhage, necrosis and cystic spaces etc.
Presence or absence of any gross involvement of adjacent structure along with
depth of the tumor was also noted. All these specimens were preserved in 10%
neutral buffered formalin for fixation for 24 hours.
For
histopathological evaluation, numbers of sections were taken from different
representative sites according to the size of specimen. While in case of small
biopsy specimen the whole specimen was processed. These representative sections
were subjected for processing on automatic tissue processor. After processing
the section were embedded in paraffin, cut with microtome at 5 micron thickness
and stained with Hematoxylin and Eosin stain. Special staining procedure like
Periodic Acid Schiff (PAS) and Reticulin stains were also done as and when
required. Histological sub typing was done according to WHO classification of
soft tissue tumours 2002. The sarcomas were further graded according to FNCLCC
grading system in to grades 1, 2, and 3 respectively. Other informations like
age, sex and detail significant history were retrieved from the medical
reports.
Results
Out of total 170 cases, 92 cases (54.1%) were males and 78 cases (45.9%)
were females with male to female ratio 1.18:1. Benign tumours were seen more in
males and intermediate & malignant in females.
Table-1: Sex Distribution of the Cases
Total Cases |
Male |
% |
Female |
% |
M:F Ratio |
170 |
92 |
54.1 |
78 |
45.9 |
1.18:1 |
The most common site of soft tissue tumours as a whole is head and neck,
followed by upper limb. Although benign tumours were seen to be maximum in head
&neck, where as intermediate in upper limb, and malignant tumours showed a
predilection for lower limb.
Table-2: Distribution of Soft Tissue Tumours
According to Tumour Differentiation and Type of neoplasm
Tumor Differentiation |
Benign |
% |
Intermediate |
% |
Malignant |
% |
Adipocytic |
113 |
66.4 |
1 |
0.59 |
1 |
0.59 |
Vascular |
19 |
11.18 |
0 |
0.00 |
0 |
0.00 |
Peripheral
Nerve Sheath Tumours |
11 |
6.47 |
0 |
0.00 |
1 |
0.59 |
Fibroblastic |
4 |
2.35 |
1 |
0.59 |
0 |
0.00 |
Fibrohistiocytic |
8 |
4.71 |
0 |
0.00 |
6 |
3.53 |
Smooth
Muscle |
0 |
0.00 |
0 |
0.00 |
2 |
1.18 |
Skeletal
Muscle |
0 |
0.00 |
0 |
0.00 |
0 |
0.00 |
chondro-osseous
tumour |
1 |
0.59 |
0 |
0.00 |
0 |
0.00 |
Tumours
of uncertain differentiation |
1 |
0.59 |
0 |
0.00 |
0 |
0.00 |
Could
not be classified |
1 |
0.59 |
0 |
0.00 |
0 |
0.00 |
Total |
158 |
92.40 |
2 |
1.18 |
10 |
5.88 |
Out of total 170 cases, 158 cases (92.4%) were benign, 2 cases (1.18%)
were malignant and 10 cases (5.88%) were classified under intermediate
category. Adipocytic tumours formed the largest group consisting of 114 cases
(67.06%). Vascular tumours were the second commonest consisting of 19 cases
(11.1%) followed by peripheral nerve sheath tumours constituting 11 cases
(6.47%).
Table-3: Age Distribution of the Cases
Age
(years) |
Benign |
(%) |
Intermediate |
(%) |
Malignant |
(%) |
Up to 10 |
6 |
3.80 |
1 |
50 |
0 |
0 |
11-20. |
10 |
6.33 |
1 |
50 |
1 |
10 |
21-30. |
34 |
21.52 |
0 |
0 |
0 |
0 |
31-40. |
24 |
15.19 |
0 |
0 |
0 |
0 |
41-50. |
43 |
27.22 |
0 |
0 |
2 |
20 |
51-60. |
18 |
11.39 |
0 |
0 |
5 |
50 |
61-70. |
13 |
8.23 |
0 |
0 |
1 |
10 |
71-80. |
10 |
6.33 |
0 |
0 |
1 |
10 |
Total |
158 |
100 |
02 |
100 |
10 |
100 |
Majority of the benign and intermediate tumours were superficial in
location, which included dermis and subcutis. However, malignant soft tissue
tumours were deeper in location, which included tumours arising from muscle,
deep to muscle. Adipocytic tumours constituted 116 cases (68.24%) of all soft
tissue tumours, out of which 114 cases were benign 1 intermediate and 1 were
malignant. Among adipocytic tumours, males outnumbered the females. The most common
site of benign adipocytic tumours was upper limb and trunk whereas of malignant
adipocytic tumours was lower limb.
The vascular tumours were the 2nd most common
soft tissue tumours and also the 2nd most common benign tumours, the majority
of which was hemangiomas. There was a wide range of age distribution in benign vascular
tumours, most commonly diagnosed in -3rd and 4th decades.
Of the 19 vascular tumours, 10 were males and 9 were females with a M: F being
1.1. Of the benign vascular tumours, 10 cases were seen in head & neck
region followed by 9 cases in the upper limb.
Out
of all soft tissue tumours, 12 cases were diagnosed as peripheral nerve sheath
tumours (7.06%). Out of themwere11 cases benign 1 malignant, out of which 10
cases were of schwannoma and 1neurofibroma. These tumours showed a wide range
of age distribution, majority were seen in 11-30 years of age i.e. in younger
age. Of the 12 peripheral nerve sheath tumours reported, 7 were males and 4
were females.
Out of 4 fibroblastic tumours, 3 cases were
of benign and 1 belonged to intermediate category. Among the4 benign cases,
1case benign fibrous tumor, 1 nodular fasciitis, 1 angiomyofibrblastoma, 1
fibromatosis. The benign fibroblastic tumours showed a wide range of age distribution
from 2nd to 7th decade. Most of the benign and intermediate fibroblastic tumours
were superficial in location.
Among 14 tumours of fibrohistocytic
differentiation, 8cases were diagnosed as benign and 6 belonged to malignant
category. Fibrohistiocytic tumours showed a wide range of age distribution from
2nd decade to 8th decade of life. Out of 8 benign cases, 6 were seen in lower
limb followed by 2 cases in upper limb. All the 6 malignant cases reported in
thigh. Only 2 cases (1.18%) smooth muscle differentiation diagnosed were of
malignant category in our study. Both cases were diagnosed in 7th decade.
Discussion
Soft tissue is defined as the supportive
tissue of various organs and the nonepithelial, extra skeletal structures
exclusive of lymphohematopoietic tissues. It includes fibrous connective
tissue, adipose tissue, skeletal muscle, blood/lymph vessels, and the
peripheral nervous system. Soft-tissue tumors constitute a large and
heterogeneous group of neoplasms. Traditionally, tumors have been classified
according to histogenetic features. However, histomorphologic,
immunohistochemical, and experimental data suggest that most sarcomas arise
from primitive, multipotential mesenchymal cells [7].
Benign tumors of soft tissue are more common
than benign tumors of bone. They can occur at almost any site, both within and
between muscles, ligaments, nerves, and blood vessels. These tumors vary widely
in appearance and behavior. Some tumors can be quite aggressive. Invasion of
nearby tissues increases the chance of an incomplete excision and the
possibility that the tumor will come back [8].
Soft tissue tumors are relatively rare and
constitute less than 1% of all the cancers. Benign mesenchymal tumors
outnumbered sarcomas by the factor of at least 100.The annual clinical
incidence of benign soft tissue tumors has been estimated up to 3000/million
population i.e.-less than 1% of all the malignant tumors [9]. Lipomas are the
most common neoplasm of mesenchymal origin arising in any location where fat is
present. At least one third of benign tumors are lipomas, one third are
fibrohistiocytic tumors and fibrous tumors, 10% are vascular and 5 % are nerve
sheath tumors [10]
In the present study, 170 soft tissue tumours
were analyzed, out of which 158 cases (92.40%) cases were benign, 2 cases (1.18%) were intermediate and 10 cases (5.88%)
were malignant tumours. This is in concordance with the study conducted by Agravat
et al [1] who analyzed 100 cases of soft tissue tumours (n=94) and tumour like
lesions (n=6), of which benign tumours formed the bulk, the results of which are
shown in the table below. In another large scale study of 8686 cases done by
Stout [11] 84.5% tumours belonged to benign category and 15.5% to malignant
category.
The age of the patients in our study ranged
from 1months to 79 years. Benign tumours were found to be more common in
younger population where as malignant tumours were commoner in 5th to 6th
decade of life. This result was in concordance with studies conducted by
Agravat et al [1] and Wimber et al [12] according to them benign tumours were
commoner in younger age group as compare to malignant tumours which were
recorded maximum in 60-70 years age group. In our study, 92 males and 78 females
were included. The male to female ratio was 1.18:1. An overall incidence of
soft tissue tumours was higher in males. This observation is in concordance
with the studies conducted by Trojani et al [13] Jemal et al [14] Gustafson [15]
Ducimetiere et al [16] as shown in table below. The slight discrepancy was due
to the fact that the later studies were done on sarcomas only and benign tumours
were not included.
However, Agravat et al [1] did not find any
sex predilection in his study, according to their study males and females were
equally affected. Head and neck was found to be the most common site involved
by benign tumors and benign vascular tumors were seen to be the most common
tumors at this site constituting 23 out of 36 cases occurring in this region.
These findings are in agreement with the study conducted by Makino et al [17]
who analysed 651 soft tissue tumors arising in the head & neck region and
found that 96% tumors (n=628) were benign while only 4% were malignant. The
bulk of benign tumours in his study was formed by haemangiomas (47%) followed
by adipocytic tumours (19%). In the present study, lower limb was the most common
site affected by sarcomas. This observation is in agreement with the study of
1660 sarcoma cases done by Mastrangelo et al [18] who observed lower limb
(n=329) to be the most common site of sarcoma followed by stomach.
In our study, visceral mesenchymal tumours
were excluded. This finding is also comparable to studies conducted by Coindre
et al [19] and Talati et al [20] who also found lower limb (extremities) to be
the most common site involved by sarcomas.
In our study of 170 cases, the most frequent
tumors were of adipocytic differentiation constituting 67.58% (n=115) followed
by 11.18% (n=19) cases of vascular tumours. Third in frequency were peripheral
nerve sheath tumours (n=12; 7.06%). These observations were somewhat similar to
the study conducted by Harpal
et al [21].
Conclusion
Pal et al; Benign tumors were more common than
malignant. Painless mass was the most common presenting symptom in our study. The
most common benign tumors were lipoma, hemangioma and schwannoma. The commonest
malignant tumors were malignant fibrous histiocytoma and leiomyosarcoma. The
benign tumors were found to be commoner inyounger population whereas malignant
tumors were seen in 5th to 6th decade. Statistically highly significant
correlation was found between age and the category of tumor.
The most common site of soft tissue tumors as
a whole was head &neck, followed by upper limb. Among benign tumors,
hemangiomas had a predilection for head & neck while lipomas were seen
commonly in upper limb. Most favoured site for malignant tumor was lower limb. The
second most common site involved by sarcomas was abdomen. The benign soft
tissue tumors were found to be superficial in location, while malignant tumors were
deep.
Importance of this study: This is important to know the different
variety of pattern of soft tissue tumours in Gandhi Nagar district.
Author contribution: First author Dr. Piyush Solanki has collected
all data and done study in his own institute. Second and corresponding author
Dr. Urvashi Mangar has prepared the study design and drafted manuscript in
presentable manner for publication in journal.
Financial support and sponsorship: Nil.
Conflicts of Interest: There are no conflicts of interest
References