Soft Tissue Sarcomas with Enigmatic Clinical Presentation- Unveiled by Histomorphology and Immunohistochemical Picture

Abstract

Soft Tissue Sarcomas (STS) are aggressive neoplasms of dismal outcome, predominantly occurring in elderly age group. Synovial Sarcomas (SS) show preponderance in adolescents and poorly differentiated histological variants need exhaustive work up employing Immunohistochemistry (IHC) and molecular pathology. Pleomorphic liposarcomas have short preoperative period and hence necessitates early identification despite being rare. Rhabdomyosarcomas are often diagnostic with skeletal muscle differentiation on histology even in the absence of embryonic or alveolar pattern. However, while dealing with small blue round cell tumours of adolescents in the absence of any specific differentiation and pattern, molecular analysis including PAX-FOXO1 fusion, FUS-ETS fusion, EWSR1-non ETS fusion, CIC and BCOR fusion is of paramount importance. In this series, we have compiled a set of four cases with diversified histomorphology, presenting at extremely uncommon sites with varying clinicoradiological profiles yet biologically behaving aggressive almost to a similar extent necessitating adjuvant therapy. An intriguing case of biphasic SS in the axilla, an uncommon site was discussed where narrowing the differentials was an uphill task. Another case of monophasic SS at yet another uncommon site (inguinolabium) with overlapping histology warranted the need to rule out the other probabilities employing IHC. The next case of pleomorphic liposarcoma encountered here needs special mention owing to low incidence and labelling it with certanity required meticulous analysis including extensive sampling and IHC. Another interesting case of pleomorphic rhabdomyosarcoma with striking histology where role of IHC was only supplementary further reinforced the vital role of histopathological examination in the diagnostic work up of sarcomas.