Tadpole cells/comma shaped cells on histopathology are seen in -
Histology of rhabdomyosarcoma 

The diagnostic cell of rhabdomyosarcoma is rhabdomyoblast.
Rhabdomyoblast contains eccentric eosinophilic granular cytoplasm rich in thick and thin filaments.
The rhabdomyoblasts may be -


Round
Elongated → Tadpole or Strap cells.


It has three variants


Embryonal
Alveolar
Pleomorphic


Rhabdomyoblasts are positive for desmin, MYOD1 and Myogenin.
Trichoepithelioma
Spideroma
Rhabdomyosarcoma
Histiocytoma