Fig. 1

Subcutaneous masses and microscopic appearance of the tumor in de novo and relapse. a Subcutaneous mass in left hypochondrium (de novo); (b): The neoplasm is restricted in the subcutaneous tissue, HE× 1 (de novo); (c): Vascular infiltration, HE× 200 (de novo); (d): Medium to large-sized atypical lymphocytes in mosaic arranging, HE× 400 (de novo); (e): Subcutaneous mass in right thigh (relapse); (f): The neoplastic cells extend into subcutaneous tissue as panniculitis-like change without corium involvement, HE× 1 (relapse); (g): Vascular infiltration, HE× 200 (relapse); (h): Small to medium-sized atypical lymphocytes with a few eosinophils infiltration, HE× 400 (relapse)