Panacea Journal of Medical Sciences

Introduction

Soft tissue tumors are defined as tumors arising from non-epithelial extraskeletal tissue of the body excluding the reticuloendothelial system, glia and supporting tissue of various parenchymal organs.^[1] The diagnosis of soft tissue tumors is based on histologic findings and rapidly advancing ancillary tests like immunohistochemistry and molecular methods like reverse transcriptase polymerase chain reaction, fluorescence in situ hybridization, and more recently next generation sequencing. Molecular alterations can also be efficiently detected by immunohistochemical markers which can be protein correlates of molecular genetic alterations protein products of gene fusion or diagnostic markers identified by gene expression profiling. ^[2]

Histopathological analysis shows that benign soft tissue tumors significantly outnumber the malignant soft tissue tumors. ^[3] Our study aims at performing category-wise analysis of benign soft tissue tumors and correlation of histopathological findings with clinical parameters.

Materials and Methods

Results

The present study included a total of 256 cases of benign soft tissue tumors. These tumors were most commonly seen in fourth decade of life followed by fifth decade and were more common in males with male to female ratio of 1.15: 1 ([Table 1])

Overall, trunk was found to be the most common site followed by upper extremity ([Table 2]).

Category-wise distribution of the tumors ([Table 3]) shows that adipocytic tumors were most common among all the tumors

Benign vascular tumors

We found 12 cases of benign vascular tumors, including lymphangioma (6 cases, 50%), arteriovenous malformation (4 cases, 33.33%) and intramuscular hemangioma (2 cases, 16,67%). [[Figure 2]]

There was an equal distribution among males and females. The vascular tumors were more common in the first three decades of life (66%). Head and neck was the commonest site for vascular tumors (58.3%). Patients with lymphangioma had presented with cystic lesion while those with arteriovenous malformation presented with pulsatile lesion.

Discussion

Out of the 256 cases of benign soft tissue tumors in our study, the maximum frequency of benign soft tissue tumors was found in fourth decade (22.65%) followed by fifth decade (18.75%), male to female ratio being 1.15:1. Male predominance for benign soft tissue tumors has been reported by other studies as well. ^[4], ^[5] Trunk was found to be the most common site (43.4%) followed by upper extremity (22.3%) in our study. Ramnani et al ^[4] who studied 120 cases of benign soft tissue tumors found maximum cases in fourth decade (27.5%) followed by third decade (22.5%). The most common site in their study was trunk (25%), followed by upper extremities (21.7%).

The mean age of patients for benign soft tissue tumors was found to be 36.6 ± 17.7 years in the study by Singh et al. ^[5] The most common sites in their study were head and neck (55cases) followed by upper extremity (48cases), out of the total 181 cases. ^[5]

[Table 4] shows comparison ofcategory wise distribution of benign soft tissue tumors in different studies.

Histopathological analysis of the tumors in different studies shows that adipocytic tumors were most common in all the studies followed by vascular tumors and nerve sheath tumors. In our study, nerve sheath tumors were more common than vascular tumors in contrast to other studies.

Most of the benign adipocytic tumors in our study were conventional lipomas (196 cases, 91.16%) and variants like angiolipoma (12 cases), spindle cell lipoma (6 cases) and myolipoma (1 case). Bera K et al ^[8] reported conventional lipoma (74 cases), angiolipoma (3 cases), spindle cell lipoma (1 case), myolipoma (1 case) and fibrolipoma (5 cases). Naik et al ^[9] in their study of soft tissue tumors found that out of 63 lipomas 58 (92.1%) were classical lipomatous tumors, whereas 5(5.9%) were fibrolipomas. They found lipomas most frequently in the fourth decade of life with upper extremity being the commonest site. Lin et al ^[10] studied 459 cases of lipomas, that included 388 conventional lipomas, 25 angiolipomas, 39 fibrolipomas, 3 myxolipomas and 4 hibernomas. Of the 25 angiolipomas in their study, 23 were noninfiltrating, while two were infiltrating type. All the angiolipomas in our study were noninfiltrating type.

In our study, trunk was found to be the most common site for conventional lipoma (51%). Almost all cases of angiolipoma were found on extremities (83%). Most common site for spindle cell lipoma was head and neck (50%). Naik et al ^[9] found upper extremity as the most common site for lipoma followed by trunk. Punia et al ^[11] studied 12 cases of angiolipoma, including eleven males and one female. Pain/tenderness was present in all except one. The locations were upper extremities or trunk. Chen et al ^[12] studied 40 cases of spindle cell lipomas that included 9 females and 31 males. The mean age was 54 years. The common sites were head, neck, shoulder and back.

The peripheral nerve sheath tumors accounted for 27 cases in our study including 13 Neurofibromas, 13 Schwannomas and one Perineurioma. Overall, nerve sheath tumors were most common in the age group of 21-30 years (66.7%). Neurofibroma and schwannoma were more common in males than in females in our study. Naik et al ^[9] encountered 15 benign peripheral nerve sheath tumors among the 108 benign soft tissue tumors in their study, out of which, 12 tumors (80%) were neurofibromas and three tumors were schwannomas. Neurofibromas occurred mainly in males (60%) in the seventh decade of life. Schwannomas, occurred in second, third and seventh decades of life, commonly in females (66.6%)

Patil et al ^[13] studied 27 cases of neurofibroma with a broad age-range (10-74 years) with female preponderance (59.2% in females), of which, 59.2% were conventional neurofibromas, 11.1% were plexiform and 29.6% were diffuse neurofibromas. The common locations were extremities and head and neck region (62.9%) in their study, whereas upper extremity and trunk (38.5% each) were the most common sites for neurofibroma in our study. In their study, five cases with conventional neurofibroma, three cases with plexiform neurofibroma and four cases of diffuse neurofibroma had Neurofibromatosis 1 (NF1). We did not encounter any case of NF1.

In our study, schwannoma was most commonly found in head and neck region (46.2%), followed by upper extremity (30.8%). Naik et al^[9] also reported head and neck region as the commonest site for schwannomas. Mujumdar et al ^[14] who studied 12 cases of Schwannomas reported upper limbs (55.55%) as the commonest site.

We diagnosed a case of plexiform schwannoma in our study. There was no evidence of any syndromic association. Berg et al ^[15] noted that plexiform schwannoma represented 4.3% of all schwannomas, and 5% of these were associated with neurofibromatosis type 2 and schwannomatosis each. We also reported one neuroblastoma like schwannoma in a case of schwannomatosis. This is a very rare variant of schwannoma, that can be misdiagnosed as neuroblastoma or primitive neuroectodermal tumor.^[16]

Perineuriomas need to be differentiated from neurofibromas, schwannomas or hybrid schwannoma- perineurioma. ^[17] We had performed immunohistochemistry study in our case. The tumor cells showed positive staining for EMA and CD34 and were negative for S-100, thus confirming the diagnosis.

The vascular tumors encountered in our study were lymphangioma (6 cases), arteriovenous malformation (4 cases) and intramuscular haemangioma (2 cases). These were more common in the first three decades of life (66%) and there was an equal distribution among males and females. Head and neck was the commonest site for vascular tumors (58.3%). Naik et al^[9] also noted head, neck and face as the most common sites for hemangiomas, 7(33.3%) out of 21 cases. Kalyani et al ^[18] in their study of vascular lesions found that benign vascular lesions were more common in females (46 cases) as compared to males (31 cases) Pyogenic granulomas were the commonest benign vascular tumors followed by capillary hemangioma and cavernous hemangiomas in their study.

In our study, for lymphangioma, four out of six patients were females, three out of six patients were in first or second decades of life and head and neck was most common site (3 cases), followed by trunk 3 (2 cases). Kang et al ^[19] studied 51 patients of lymphangioma. They observed that lymphangiomas predominantly occurred in females. In their study, 56.9% of the patients were under 10 years age, mean age being 16.5 years and trunk (43.6%), was the most common site followed by extremities (30.9%) and head and neck. (20.0%).

The rarely found tumors in our study were benign fibrous histiocytoma and glomus tumor which were relatively rare in other studies as well.

Conclusion

To conclude, though lipomas form the bulk of benign soft tissue tumors, there is a considerable variety among the remaining small proportion of these tumors. Most of these have some peculiarities regarding the age, gender and site-wise distribution. Knowledge of the clinicopathological profile can be helpful to the clinician for provisional diagnosis and further management of soft tissue tumors. But histopathology is the ultimate gold standard.

Conflict of Interest

None.

Source of Funding

None.