Abstract
Background : Spindle cell rhabdomyosarcoma (Sp-RMS) is a rare tumor arising in the head and neck region. We report a case of Sp-RMS of the left parotid gland that was detected after surgery for myoepithelial carcinoma (MC) of the left parotid gland.
Case : The patient was a 30-year-old woman. MRI and PET-CT showed a mass in the postoperative area, and aspiration cytology was performed. The tumor cells contained spindle-shaped nuclei, with some cytoplasmic inclusion bodies in the nuclei and rhabdomeres in the cytoplasm. In addition, caudal rhabdomyoblasts were observed. Histological images showed spindle-shaped tumor cells proliferating in bundles or in intricate structures. Immunohistochemical analysis revealed positive staining of the tumor cells for desmin, HHF35, myogenin, and myoD1, and negative staining for S-100a, AE1/AE3, αSMA, and calponin, leading to the diagnosis of Sp-RMS.
Conclusion : Presence of cytoplasmic inclusion bodies in the tumor cell nuclei, and presence of rhabdomyoblasts and intracytoplasmic striations may suggest the diagnosis of Sp-RMS.
