Göğüs duvari yerleşimli, nadir bir yumuşak doku sarkomu: Berrak hücreli sarkom A rare chest wall localized soft tissue sarcoma: Clear cell sarcoma

The clear cell sarcomas of soft tissue are rare tumors originating from neural crest cells and presenting with poor prognosis. By the reason of the resemblance of histological properties to malign melanoma (eg. the immunoreactivity to S100 and HMB45, the presence of melanosomes ultrastructurally), these tumors are also defined as malign melanomas of soft tissue. But distinctively from cutaneous melanoma, clear cell sarcoma is almost always deeply localized and the biological behaviour of the last one is also different. The differential diagnosis between clear cell sarcoma and desmoplastic or spindle cell malign melanoma may be more difficult because of the dermal localization of the last ones. In our case, it was observed an infiltrative tumor composed of uniform seeming cells with vesicular nuclei, distinct nucleoli, pale eosinophilic and sometimes clear, scant cytoplasms, in addition to necrotic areas. On immunohistochemical examination, the tumoral cells showed a positive immunoreactivity to vimentin, S100, HMB45, and SMA, while showing negative immunoreactivity with CD34, PanCK, EMA, LCA, CD99 and desmin. Ki-67 proliferation index was determined as approximately 50%. Because of deep localization and different morphological-immunohistochemical findings of the tumor, the case was diagnosed as “clear cell sarcoma”. It was observed a tumor with similar morphology in the biopsy sample taken from vertebra of the patient one month later than the first material and this was commented as the metastasis of the tumor to vertebra.