PMC5806434_01
(a) Clinical feature of the lesion. (b) Periapical view of the lesion, note the widening of PDL in lateral incisor, canine, and first premolar.
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F1
Intraoral examinations revealed a firm, sessile, and pink exophytic ulcerative mass with a lobulated surface, in maxillary left buccal gingiva, which extended from canine to distal of the first molar [Figure 1a]. In periapical radiography, the PDL widening was seen in teeth number 10, 11 and 12 [Figure 1b].
(a) Tumoral cells with abundant eosinophilic cytoplasm resembling "Rhabdomyoblasts" are seen. Note two atypical mitosis at central and mid-low of the picture (H and E, x400). (b) Neoplastic cells with pleomorphism and scattered bizarre cells (H and E, x400). (c) Malignant cells with abundant eosinophilic cytoplasm. Note straplike rhabdomyoblasts (x400).
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F2
The highly cellular neoplastic tissue was composed of predominant spindle cells in which some foci exhibited a fascicular pattern [Figure 2a]. In addition, marked cellular pleomorphism and nuclear hyperchromasia with prominent nucleoli, scattered atypical mitotic figures, and bizarre giant cells were identifiable among tumoral cells [Figure 2b]. In addition, scattered tumor cells with abundant eosinophilic cytoplasm and strap-like feature resembled "Rhabdomyoblast" [Figure 2c].
(a) Positive immunoreactivity of tumoral cells with anti-myoD1 antibody (x400). (b) Positive immunoreactivity of tumoral cells with anti-myogenin antibody (x400).
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F3
Using immunohistochemical (IHC) staining, the tumor cells were positively reacted with specific markers for myogenic differentiation such as anti-Desmin, anti-Myogenin, and anti-MyoD1 antibodies [Figure 3].