PMC9177093_01
(a) Markings showing the mass and the modified Blair's incision in the preauricular region. (b): CT scan showing hypodense lesion occupying the left masseter muscle. (c) Intraoperative picture showing facial nerve and its branches after superficial parotidectomy with small nodular mass in the masseter muscle.
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On local examination, single 3x2 cm, well defined, non tender, firm mass was palpated in the left parotid region in front of the left angle of mandible with no local rise in temperature and the skin over the swelling and surrounding region was normal (Figure 1a). Patient underwent CT scan which revealed a hypodense lesion occupying the left masseter muscle whereas with contrast, the lesion showed intense enhancement (Figure 1b). Facial nerve along with all its branches were preserved (Figure 1c).
(a,b) Tumor cells are arranged in sheets with interspersed foci of necrosis, congestion, haemorrhage, cystic degeneration and large blood vessels (H&E stain, 10x and 20x respectively). (c) Epithelioid to plump spindle shaped tumor cells having large, moderately pleomorphic round to ovoid nuclei, coarse chromatin, moderate to abundant eosinophilic cytoplasm with few mitotic figures and rich network of small caliber blood vessels are noted (H&E stain, 40x). (d) Immunohistochemistry shows nuclear positivity for FLI-1.
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Sections from the globular mass showed pseudo-encapsulated tumor composed of tumor cells arranged in sheets and interspersed foci of necrosis, congestion, hemorrhage and cystic degeneration (Figure 2a-b). Tumor cells were epithelioid to plump spindle shaped with a rich network of small caliber blood vessels as well as compressed to dilated vascular spaces lined by similar plump cells having large, moderately pleomorphic round to ovoid nuclei, coarse chromatin, prominent nucleoli and moderate to abundant eosinophilic cytoplasm (Figure 2c). FLI-1 was positive (Figure 2d), S-100 was focal positive and Ki-67 proliferation index was 30-40%.