PMC4860917_01
Extra orally diffuse swelling over the right maxillary sinus extending onto the ala of nose
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F1
Extraorally, the patient had diffuse swelling over the right maxillary sinus region extending over the ala of the nose [Figure 1].
Intraoral examination revealed unhealed socket of 17 surrounded by everted margins and necrosed bone within
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F2
Intraorally, there was an unhealed socket of 17 with necrosed bone inside, surrounded by everted margins [Figure 2].
Contrast-enhanced computed tomography exhibiting nonhomogeneous enhancing lesion destroying walls of maxillary and ethmoid sinus, upper right alveolus and extending into masticator space and infratemporal region
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F3
No cervical lymphadenopathy was evident [Figure 3].
Basaloid islands and cord-like structures infiltrating the overlying epithelium, areas of mucous cells and mucin filled spaces are also seen (H&E stain, x40)
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F4
These structures were seen infiltrating into the overlying epithelium [Figure 4] and showed two cell populations: peripheral tall columnar and central round to ovoid cells.
Peripheral palisaded arrangement of columnar cells and central loose cells showing stellate reticulum-like appearance with interspersed mucous cells (H&E stain, x400)
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F5
Some of the central areas showed the presence of mucous cells and mucin filled spaces [Figure 5].
Tumour cells forming canalicular and tubular structures enclosing haemorrhagic spaces (H&E stain, x100)
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F6
At places, the tumor cells formed canalicular structures enclosing hemorrhagic spaces [Figure 6].
Calretinin negativity ruled out ameloblastoma (IHC stain, x400)
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F7
Negative immunostaining for calretinin ruled out ameloblastoma [Figure 7].
Periodic acid-Schiff (PAS) stain positivity at periphery of islands and cytoplasm of central cells (PAS stain, x400)
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F8
Periodic acid-Schiff stain revealed patchy positivity at the periphery of islands and in the cytoplasm of the central cells indicating a salivary gland origin [Figure 8].
Calponin immunostaining shows strongly positive peripheral cells of the lesion suggestive of myoepithelial cells (IHC stain, x400)
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F9
On immunostaining, strong positivity for calponin in the peripheral basaloid cells was suggestive of myoepithelial cells [Figure 9].
CK 19 showed patchy positivity in the center of islands at places and the tubular structures (IHC stain, x400)
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F10
Cytokeratin (CK 19) positivity in the central cells and cells in cords was suggestive of luminal cells [Figure 10].
Ki-67 index <5% (IHC stain, x400)
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F11
Ki-67 index was <5% [Figure 11].