20 year old, soft to firm reddish swelling, progressing in size over the precordium. Histopathological examination showed the following.  What could be your possible diagnosis?
Ref. Robbins Pathology. 9th edition. Page. 517
 
Hemangioma
These tumours are slow growing and are generally asymptomatic unless they exert mass effect on sensitive structures.
 
Microscopy

Closely packed spindle cells with spaces containing little blood
Lumens may be thrombosed or organized, hemosiderin present due to rupture
Scant fibrous stroma
Hemangioma
Fibroadenoma
Lipoma
Dermatofibroma