Pathology Quiz Online

                   February 2005        Case - 44

                                                      Dr  Sampurna Roy  MD 

                 Clinical History:  A 20 year old female with a slow growing tender mass( 3cm in diameter)

            on the left ankle. It  was intimately bound to the underlying tendoaponeurotic structures.

            The overlying skin was not involved.

            Radiological examination :- A soft tissue mass without calcification. The underlying bone was not

            involved.

            The tumour was enucleated and after postoperative radiotherapy a wide local excision was done.

            The patient was symptomless 4 years after operation.

                 Gross:
                 The cut surface has a greyish-white appearance with brownish patches.

               Diagnostic clues:  

                 The tumour has a nested growth pattern and consists of polygonal tumour cells with

           clear cytoplasm  and pale eosinophilic spindle cells separated by  dense fibrous septa.

           These cells have vesicular nuclei and prominent nucleoli.Which tumours show clear cell change?

                Immunohistochemistry:

                 S100 protein- Positive ; HMB45- Positive ; Smooth muscle actin- Negative

            S100 protein is strongly positive.   

            Reticulin stain:   Nested architecture with loose meshwork of reticulin fibres ,

                        which  surround  the individual nests of tumour cells .

                                                            DIAGNOSIS: