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ORIGINAL ARTICLE
Year : 2023  |  Volume : 28  |  Issue : 1  |  Page : 59-66

Histopathological evaluation of benign soft tissue lesions at Nnamdi Azikiwe University teaching hospital, Nnewi, south-east Nigeria: A 9-year review


1 Department of Anatomic Pathology and Forensic Medicine, Nnamdi Azikiwe University, Awka, Nigeria
2 Department of Morbid Anatomy and Forensic Medicine, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Osun State, Nigeria
3 Dermatology Department, Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi, Nigeria

Date of Submission13-Jun-2022
Date of Decision22-Aug-2022
Date of Acceptance01-Oct-2022
Date of Web Publication13-Dec-2022

Correspondence Address:
Ifeoma F Ezejiofor
Department of Anatomic Pathology and Forensic Medicine, Nnamdi Azikiwe University, Awka
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijmh.IJMH_49_22

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  Abstract 

Background: Soft tissue lesions are remarkably diverse and range from inflammatory, self-limited lesions to neoplasm. The diversity of these lesions frequently poses a diagnostic challenge to pathologists and remains a subject of interests. Lack of research on soft tissues in our setting has prompted the need to study them. Objectives: The aim of this study was to determine the benign lesions of soft tissues with respect to age, sex, anatomic site, and histologic types. It also aimed to determine the baseline data of benign soft tissue lesions in Nnewi, Nigeria. Materials and Methods: This study reviewed all histologically diagnosed benign soft tissue lesions at the Histopathology Department of Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi, Nigeria from 2011 to 2019 and classified the tumors using the 2020 WHO Classification of Soft Tissue Tumours. Results: A total of 351 cases of soft tissue lesions were diagnosed during the study period, out of which 251 were benign lesions and accounted for 71.5% (251/351) of all soft tissue lesions, whereas 28.5% (100/351) of the cases were malignant. The benign lesions included inflammatory and benign neoplasm, of which neoplasm accounted for the majority of the cases with a frequency of 94.0% (236/251), whereas inflammatory lesions accounted for 5.9% (15/251). The 236 benign soft tissue tumors diagnosed had a male-to-female ratio of 1: 1.4 with a mean age (SD) of 37.5 (19.5) years. The most frequent occurrence of benign tumors was seen in the fourth decade with 52 cases (21.0%), followed by fifth decade with 42 cases (16.7%). Adipocytic tumors were the commonest with a frequency of 54.0% (135/251), followed by peripheral nerve sheath tumors (PNSTs) with 12.4% (31/251) and then vascular and fibroblastic/myofibroblastic tumors with 10.8% (27/251) and 5.6% (14/251), respectively. Lipoma is the most common histologic type of benign soft tissue tumor and the only benign adipocytic tumor. This is followed by hemangioma 9.6% (24/251) and then neurofibroma 7.6% (19/251). Lipoma accounted for 37.09% (135/351) of all soft tissue lesions and the majority of them were seen in the fourth decade, whereas hemagioma and neurofibroma occurred more at the first decade. The most common anatomic distributions of these benign tumors were lower extremities with 23.5% (n = 59/251), followed by trunk 21.1% (n = 53). The major inflammatory lesions were tuberculoid granulomatous inflammation and panniculitis with 2.3% (6/251) of cases each. Others were necrotizing fasciitis (n = 2) and eosinophilic myositis (n = 1). Conclusion: Benign soft tissue tumors had a slight female preponderance. Lipoma is the single most common benign soft tissue neoplasm, whereas tuberculosis and panniculitis were the two most common inflammatory soft tissue lesions. Histopathological evaluation of these lesions still stands as a gold standard in their diagnosis.

Keywords: Benign soft tissue tumor, inflammatory soft tissue lesions, lipoma, panniculitis and tuberculosis, south-eastern Nigeria, WHO classification


How to cite this article:
Ezejiofor IF, Olaofe OO, Ezejiofor OI, Ozor NS, Osonwa NC. Histopathological evaluation of benign soft tissue lesions at Nnamdi Azikiwe University teaching hospital, Nnewi, south-east Nigeria: A 9-year review. Int J Med Health Dev 2023;28:59-66

How to cite this URL:
Ezejiofor IF, Olaofe OO, Ezejiofor OI, Ozor NS, Osonwa NC. Histopathological evaluation of benign soft tissue lesions at Nnamdi Azikiwe University teaching hospital, Nnewi, south-east Nigeria: A 9-year review. Int J Med Health Dev [serial online] 2023 [cited 2023 Jan 27];28:59-66. Available from: https://www.ijmhdev.com/text.asp?2023/28/1/59/363252




  Introduction Top


Benign soft tissue tumors are mesenchymal proliferations of the body which have a limited capacity for autonomous growth and closely resemble normal tissue.[1] They have no capacity to invade locally or recur following excision. Benign soft tissue tumors outnumber malignant tumors by a wide margin.[1]

Soft tissue lesions can occur at any age and in any part of the body, but most cases arise from the large muscles of the extremities, the chest wall, the mediastinum, and the retroperitoneum. They can occur at almost any site, both within and between muscles, ligaments, nerves, and blood vessels.[1] It can arise from both the mesodermal and ectodermal layers and has the capacity to mature into several adult cell lines or tissues such as striated and smooth muscles, adipose tissues, fibrous tissues, blood vessels, and peripheral nervous system.[1],[2],[3],[4],[5]

The World Health Organization (WHO) in 2020 classified soft tissue tumors into 12 groups with each group being further subdivided into benign, intermediate, and malignant subgroups. They include adipocytic tumors, fibroblastic/myofibroblastic tumors, fibrohistiocytic tumors, vascular tumors, pericytic (perivascular) tumors, smooth muscle tumors, skeletal muscle tumors, extra-gastrointestinal stromal tumors, chondro-osseous tumors, PNSTs, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas of bone and soft tissue.[6]

Accurate diagnosis of benign soft tissue lesions can be achieved by proper clinical history taken such as age, duration, location, size, and pathological examination. These are all contributory in making differential diagnosis of these benign soft tissue lesions.

The dearth of information on this topic in Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi, Nigeria has nessciated the need to study the lesions and also provide the baseline data in NAUTH for further research.


  Materials and Methods Top


This is a retrospective study of soft tissue biopsies received at the Histopathology Department, Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi, Nigeria from January 2011 to December 2019. Hospital ethical approval was obtained from the Ethics Committee of NAUTH, Nnewi, Nigeria (registration number: NAUTH/CS/66/VOL8/59).

Laboratory request forms and duplicate copies of histological reports were retrieved, and relevant clinical information and histological type of the tumors were extracted. Only soft tissue cases with adequate records were included, whereas malignant cases and cases that had unrepresentative tissues and incomplete clinical details were excluded.

The tissues were initially fixed in 10% formal saline, processed, and embedded in paraffin wax. They were then sectioned and mounted on a glass slide and stained with regular histochemical stain [hematoxylin and eosin (H & E)]. The slides were reviewed by the authors using a multi-headed light microscope (CARL ZEISS®). Diagnostic accuracy and reproducibility were worked on by implementation of diagnostic second and even third opinion and sometimes with collaboration from other Centers. Data were analyzed using statistics software Statistical Product and Service Solutions (SPSS) Incorporated, version 21 (Chicago, IL, USA) and results presented as tables and pie and bar charts.


  Results Top


Three hundred and fifty-eight cases of soft tissues were diagnosed in the study period, out of which 351 cases fulfilled the inclusion criteria but only 251/358 (70.1%) had adequate records for inclusion as benign soft tissue lesions, 100/358 (27.9%) cases were malignant soft tissue lesions and were therefore excluded, the remaining 7/358 (2.0%) cases were also excluded from the study due to inadequate records ranging from unrepresentative tissue to incomplete clinical details. Two hundred and fifty-one cases were benign lesions and accounted for 71.5% (251/351) of all soft tissue lesions, whereas 28.5% (100/351) of the cases were malignant. The benign lesions include inflammatory lesions and benign neoplasm, of which neoplasm accounted for majority of the cases with a frequency of 94.0% (236/251), whereas inflammatory lesions accounted for 5.9% (15/251).

The WHO classified the soft tissue neoplasm into 12 groups which were further subdivided into benign, intermediate, and malignant tumors. Adipocytic tumors were the commonest group in this study with a frequency of 53.7% (135/251), followed by PNSTs 12.4% (31/251) and then vascular and fibroblastic/myofibroblastic tumors with 10.7% (27/251) and 5.6% (14/251), respectively.

Lipoma [Figure 1] is the most common histologic type of benign soft tissue tumor and only benign adipocytic tumor. It accounted for 53.7% (135/251) followed by hemangioma [Figure 2] 9.6% (24/251) and then neurofibroma 7.6% (19/251). Lipoma accounted for 38.5% (135/351) of all soft tissue lesions and majority of them were seen in the fourth decade, whereas hemagioma and neurofibroma occur more at the first decade and accounted for 6.6% (24/351) and 5.2% (19/351) of all soft tissue lesions, respectively. Neurofibroma (19/251) and Schwannoma [Figure 3] (7/251) were common PNSTs. Hemangioma (n = 24) is the commonest vascular tumor, whereas fibromatosis (n = 5) is the common fibroblastic/myofibroblastic tumor [Table 1].
Figure 1: Well-encapsulated mesenchymal neoplasm composed of lobules of mature adipocytes separated by a thin hyalinized stroma (lipoma)

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Figure 2: Lobular capillary hemangioma composed of nodules of small capillary-sized vessels separated by thick fibrous septa

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Figure 3: Schwannoma composed of alternating Antoni A and B areas with Antoni A areas having compact spindle cells with occasionally, clear intranuclear vacuoles and show Verocay bodies

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Table 1: Classification of benign soft tissue tumors and the frequencies of the histologic diagnosis

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Tuberculoid granulomatous inflammation and panniculitis were the major inflammatory soft tissue lesions seen with 2.4% (6/251) of cases each. Others were necrotizing fasciitis (n = 1), subcutaneous fat necrosis (n = 1), and eosinophilic myositis (n = 1).

There is a slight female preponderance of benign soft tissue tumors with male-to-female ratio of benign tumor seen as 1: 1.4 with mean age (SD) of 37.5 (19.5) years. Majority of the cases of benign tumors were seen in the fourth decade with a frequency of 21.3% (53/251) followed by fifth decade with 44 cases (17.7%) [Figure 4].
Figure 4: Age-group and sex distributions of benign soft tissue lesions showing higher percentage in female than male with majority of cases seen in fourth decade

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The commonest histologic types seen in both sexes are still adipocytic tumors (lipoma), followed by neurofibroma with hemangioma having equal distributions in both sexes. The second most common tumor group in females is fibroblastic/myofibroblastic tumors (n = 14), followed by vascular tumors (n = 13) and then PNSTs (n = 11), whereas in the male counterpart the second commonest tumor group is PNSTs (n = 21), followed by vascular tumors (n = 15) and then fibroblastic/myofibroblastic tumors (n = 12) [Table 2].
Table 2: Histopathological types and sex distribution of benign soft tissue tumors

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Majority of lipoma cases were seen in the fourth decade, whereas hemagioma and neurofibroma occur more at the first decade [Table 3].
Table 3: Distribution of benign soft tissue tumors according to histopathologic types and age groups

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The most common anatomic site of benign soft tissue tumors in this study was lower extremities with 23.5% (n = 59), followed by trunk [21.1% (n = 53)] [Table 4].
Table 4: Anatomic distribution of benign soft tissue lesions with lower extremities being the commonest location followed by trunk

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  Discussion Top


Benign soft tissue lesions are remarkably diverse and range from inflammatory, self-limited lesions to neoplasm. The diversity of these lesions frequently poses a diagnostic challenge to pathologists and remains a subject of interests. In this study, 351 cases of soft tissues were analyzed, out of which 251 were benign lesions and accounted for 71.5% (251/351), whereas 28.5% (100/351) of the cases were malignant. Benign neoplasms were 94.04% (236/251) and inflammatory lesions were 5.9% (15/251). Majority of soft tissue cases in this study were benign tumors with a benign-to-malignant tumors ratio of 2.5:1. These findings are in tandem with Enzinger and Weiss,[1] Myhre Jenson et al.,[7] and Angervall et al.[8] and also similar to most studies in literatures. Vhriterhire et al.[9] in Makurdi, Nigeria, Syam Sundar Rao et al.,[10] Jain et al.,[11] Gogoi et al.,[12] and Singh et al.[13] had ratios of 2:1, 8:1, 10:1, 13:1, and 2:1 (all Indians).

In this study, we observed that more cases of benign soft tissue tumors were seen in females than in males with a male-to-female ratio of 1: 1.4 and a mean age (SD) of 37.5 (19.5) years which is similar to the study by Vhriterhire et al.[9] in Makurdi, Nigeria who reported M: F=1:1.2 and a mean age of 35.05 ± 18.9 years but contrary to most studies in Asian countries by Syam Sundar Rao et al.[10] and Singh et al.,[13] where there is a slight male preponderance. However, Beg et al.[14] reported equal distributions of all soft tissue tumors with an M: F ratio of 1:1.

This study also observed adipocytic tumors as the commonest group [54.2% (135/251)], followed by PNSTs [12.4% (31/251)]. This is comparable to the study by Jain et al.,[11] who reported adipocytic tumor (50.27%) as most common soft tissue tumor followed by vascular tumors (20%) and PNSTs (19.72%). Research done by Singh et al.[13] in India also reported similar findings with adipocytic tumors being the commonest (34.1%) followed by vascular tumors (18.5%) and PNSTs (11.1%) and that lipoma formed the bulk of benign adipocytic tumors (29.3%). Lipoma is the only adipocytic tumor found in this study and accounted for 37.09% of all soft tissue cases. Lipoma was comparatively common in females (n = 85) than in males (n = 50) and appeared most frequently in the age group 31–50 years (n = 65) with maximum cases seen in the fourth decade (n = 35). These findings are similar to the research done by Vhriterhire et al.,[9] in which 49 cases (38.9%) out of 188 soft tissue tumors were lipoma. Syam Sundar Rao et al.[10] also reported that the commonest benign soft tissue tumor is lipoma (56.09%) and was most common in the age group 21–50 years with maximum cases in 31–41 years (43.47%) but had male preponderance.

Hemangioma was the second commonest benign soft tissue tumors with 24 cases (9.6%) and were maximum in infancy and childhood age group (0–10 years) with equal distributions in both sexes. These findings are similar to research carried out by Syam Sundar Rao et al.,[10] in which hemangiomas [12 (14.63%)] were the second commonest and seen majorly in the age group 0–30 years but with male preponderance. Singh et al[13] also reported vascular tumors as the second most common tumors (18.51%), among which hemangiomas were the most common (n = 44). Agravat et al.,[15] Kransdorf,[5] and Makino[16] had observations similar to this study.

Neurofibroma 7.6% (n = 19) and schwannoma (n = 7) were the most common benign PNSTs and the third commonest benign soft tissue tumors. Neurofibromas such as hemangioma were maximum in infancy and childhood in the age group 0–10 years while schwannoma occurred in the fourth decade (31–40 years). Both neurofibroma and schwannoma occurred more in male counterpart with 11 out of 19 and 4 out of 7 cases, respectively. These findings are in tandem with the report by Singh et al. who reported schwannoma and neurofibroma as the most common benign PNSTs but with higher percentage of schwannoma (n = 14) than neurofibroma (n = 10) and that they formed the third commonest benign soft tissue tumor.[13] Syam Sundar Rao et al. had a similar report with 12.9% (n = 10) for schwannoma and 9.75% (n = 8) for neurofibroma, but reviewed that schwannomas were seen in the third decade, whereas neurofibroma occurred in the age group 21–50 years.[10]

Fibroblastic or myofibroblastic tumors were the fourth commonest groups [5.6% (14/251)], with fibromatosis (n = 5) and fibroma (n = 4) occurring in second and first decades of life, respectively, with female dominance in fibromatosis and fibroma. Three studies also reported fibroblastic tumors as the fourth most common soft tissue tumor and fibroma and fibromatosis as the commonest histologic types.[7],[13],[15]

Tumors of uncertain differentiation were the fifth commonest with 4.8% (n = 11), whereas fibrohistiocytic tumors were the sixth most common (n = 10; 4.0%) benign soft tissue tumors with benign fibrous histiocytoma (BFH) (n = 3) and giant cell tumor of tendon sheath (GCTT) (n = 7) as the only benign soft tissue tumors in this group and occurred in the age groups 31–70 and 0–40 years, respectively. This is similar to research done by Singh et al.,[13] who found BFH and GCTT as the most common fibrohistiocytic tumors with a wide range of age distribution (18–70 years). He also found tumors of uncertain differentiation to constitute 4.45% (n = 12) of all STTs, similar to studies by Kransdorf[5] and Silver et al.[17]

This study also observed that the most common anatomic site of benign soft tissue tumors was lower extremities with 23.5% (59/251), followed by trunk 21.1% (53/251) then head and neck 15.5% (39/251). This report is similar with review from Enzinger F.M.S.W et al. and many studies in most literatures.[1]


  Conclusion Top


Benign soft tissue tumors are heterogeneous tumors which differentiate into different cell lines. Our study has highlighted the affected age groups, anatomic sites, and sex predilections of different histologic types. This study also showed a slight female dominance in benign soft tissue tumor in our environment, similar to some studies in Nigeria.

Acknowledgements

Special appreciations to Ezeh Ebere for her assistance in the data entry for this work. We also appreciate the Histopathology Laboratory Records Staff for their assistance in the provision of all necessary records used in the preparation of this work.

Financial support and sponsorship

This work did not receive any form of financial support in the form of funding, grants or drugs.

Conflicts of interest

The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Authors’ contributions

This is to certify that the authors contributed to the conception, data collection, analysis, and intellectual contents of this article.

Data availability

The data used to support the findings of this study are available from Histopathology Laboratory Records and Laboratory Request Forms, in the Department of Histopathology, Nnamdi Azikiwe University Teaching Hospital, Nnewi.

Ethical approval

Ethical approval was obtained from the Ethics Committee, Nnamdi Azikiwe University Teaching, Hospital, Nnewi, Nigeria (registration number: NAUTH/ CS/66/VOL8/59).



 
  References Top

1.
Enzinger FM, Weiss SW Soft tissue tumours. In: Enzinger FM, editor. Incidence, pathogenesis, classification of soft tissue tumors. 5th ed. Philadelphia: Mosby Elsevier; 2007. pp. 1–4.  Back to cited text no. 1
    
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Burningham Z, Hashibe M, Spector L, Schiffman JD The epidemiology of sarcoma. Clin Sarcoma Res 2012;2:14.  Back to cited text no. 2
    
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Adigun IA, Rahman GA A review of soft tissue sarcoma. Niger J Med 2007;16:94-101.  Back to cited text no. 3
    
4.
Kransdorf MJ Malignant soft tissue tumors in a large referral population; distribution of specific diagnosis by age, sex and location. Am J Roentgenol 1995;164:129-34.  Back to cited text no. 4
    
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Kransdorf MJ Benign soft-tissue tumors in a large referral population: Distribution of specific diagnoses by age, sex, and location. Am J Roentgenol 1995;164:395-402.  Back to cited text no. 5
    
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Sbaraglia M, Bellan E, Dei Tos AP The 2020 WHO classification of soft tissue tumours: News and perspectives. Pathologica 2021;113:70-84.  Back to cited text no. 6
    
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Myhre-Jenson O et al. Histopathological staging in soft tissue tumours in relation to in 261 surgically treated patients. Acta Pathol Microbial Immunol Scand A 1983;91:145.  Back to cited text no. 7
    
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Angervall L, et al. The diagnosis and prognosis of soft tissue tumors. Semin Diagn Pathol 1986;3:240-58.  Back to cited text no. 8
    
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Vhriterhire RA, Ngbea JA, Akpor IO Histological spectrum of soft-tissue tumors in a tertiary hospital. Sahel Med J 2020; 23:170-8.  Back to cited text no. 9
    
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Syam Sundar Rao B, Grandhi B, Shanthi V, Bheemaraju V, Mohan Rao N, Goel A Clinico pathological evaluation of benign and malignant soft tissue tumors—2 years retrospective study. JMSCR 2016;04:10822-32  Back to cited text no. 10
    
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Jain P, Shrivastava A, Malik R Clinicomorphological assessment of soft tissue tumors. Sch J App Med Sci 2014;2: 886-90.  Back to cited text no. 11
    
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Gogoi G, Borgohian M, Saikia P, Patel B, Hazarika RK, Brahma RC, et al. Histopathological study of soft-tissue tumors and review of literature of rarer types. Int Clin Pathol J 2017; 4:151-61.  Back to cited text no. 12
    
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Singh HP, Grover S, Garg B, Sood N Histopathological spectrum of soft-tissue tumors with immunohistochemistry correlation and FNCLCC grading: A north Indian experience. Niger Med J 2017;58:149-55.  Back to cited text no. 13
    
14.
Beg S, Vasenwala SM, Haider N, Ahmad SS, Maheshwari V, Khan MA A comparison of cytological and histopathological findings and role of immunostains in the diagnosis of soft tissue tumours. J Cytol 2012;29:125-30.  Back to cited text no. 14
    
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Agravat AH, Dhruva GA, Parmar SA Histopathology study of soft tissue tumours and tumour like lesions. J Cell Tissue Res 2010;10:2287-92.  Back to cited text no. 15
    
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Makino Y A clinicopathological study on soft tissue tumours of the head and neck. Pathol Int 1979;29:389-408.  Back to cited text no. 16
    
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Silver WP, Harrelson JM, Scully SP Intramuscular myxoma: A clinicopathologic study of 17 patients. Clin Orthop Relat Res 2002;403:191-7.  Back to cited text no. 17
    


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