Multinodular adult rhabdomyoma in female: A rare case report

Rhabdomyomas are rare benign mesenchymal tumors of striated muscle origin. These are classified as cardiac and extracardiac types. Extracardiac type is further classified as adult, fetal and genital types. Adult rhabdomyoma represents <2% of all muscular tumors. It mostly occurs in adults (median: 60 years). Males are more commonly affected (M:F = 3:1) and usually present as solitary lesion. We report a rare case of multinodular adult rhabdomyoma arising from the floor of the mouth. A 55-year-old female presented with a painless, soft, mobile, nontender and multinodular swelling in the right submandibular region and the floor of the mouth for 2 months. Fine-needle aspiration cytology showed cellular smears of large elongated to round cells with abundant eosinophilic granular cytoplasm, small nuclei and occasionally prominent nucleoli. Histology revealed partially encapsulated lesion showing sheets of large, oval to polygonal cells with abundant deeply eosinophilic and granular cytoplasm, with small peripherally placed nuclei with few cells showing prominent nucleoli. Prominent cytoplasmic vacuolations (periodic acid-Schiff positive) were present. The cells were positive for desmin and myogenin. This case is an extremely rare presentation of multinodular adult rhabdomyoma in a female. The correct identification of this lesion is important to avoid an unnecessarily aggressive resection, yet providing potentially curative therapy.