PMC5748093_01
Clinical presentation. Intraoral examination showed a reddish white, lobular, soft gingival mass on the left mandibular alveolar ridge in the region of mandibular left third molar.
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There was no ulceration or surface erosion (Figure 1).
Incisional biopsy. Photomicrograph of incisional biopsy tissue showing (a) hypercellular lesional tissue proliferating in sheets with hemorrhagic background, 4x H&E; (b) pleomorphic epithelioid cells with vesicular nucleus, prominent nucleoli, 40x H&E; (c) tumor cells radiating out from blood vessel in streaming fashion (pleomorphism and atypical mitoses are also seen), 40x H&E; (d) tumor cells with rhabdoid cells appearance and pleomorphism, 100x H&E.
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The gingival growth was biopsied under local anesthesia, the findings of which were suggestive of proximal variant of epithelioid sarcoma (ES) (Figures 2-2).
Immunohistochemistry. Immunohistochemical markers showing positive cytokeratin (a), vimentin (b), epithelial membrane antigen (d), and negative S100 (c).
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Immunohistochemistry performed on the tissue showed diffuse strong cytoplasmic positivity for pancytokeratin and vimentin (Figures 3 and 3). EMA was strongly positive with membranous staining of the tumor cells in >75% of the tumor cell population (Figure 3). All other markers of S100 (Figure 3), desmin, CD45, CD31, and CD34 (Figure 4) were negative for the tumor cells.
Immunohistochemistry CD34. Tumor cells negative for CD34, 4x, and 40x (inset).
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All other markers of S100 (Figure 3), desmin, CD45, CD31, and CD34 (Figure 4) were negative for the tumor cells.
Contrast-enhanced computed tomography. CECT axial section shows ill-defined heterogeneously enhancing soft tissue lesion in the left submandibular region with no obvious bone erosion. Few subcentimetric nodes are seen along bilateral submandibular and upper jugular chains.
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To rule out the possibility of a primary elsewhere in the body, advanced imaging modalities like ultrasound abdomen, contrast enhanced CT (CECT) of head and neck region, and positron emission tomography (PET) scan were carried out, all of which revealed the gingival growth to be the primary lesion (Figures 5 and 6).
Positron emission tomography. 18F-FDG PET-CT axial section shows hypermetabolic lesion involving the region of mandibular left third molar and level IB cervical lymph node.
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To rule out the possibility of a primary elsewhere in the body, advanced imaging modalities like ultrasound abdomen, contrast enhanced CT (CECT) of head and neck region, and positron emission tomography (PET) scan were carried out, all of which revealed the gingival growth to be the primary lesion (Figures 5 and 6).
Excisional biopsy. Photomicrograph of excisional biopsy showing (a, b) dysplastic epithelium proliferating into connective tissue, 4x H&E; (c) pleomorphic cells with vesicular nucleus, rhabdoid appearance, 10x H&E; (d) sheets of biphasic tumor cells with spindle cells in inset, 10x H&E.
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Histopathologic examination following excision revealed overlying parakeratinized stratified squamous epithelium at either end with ulceration and discontinuity at the centre (Figures 7 and 7). The ulcerated area showed abundant epithelioid cells in loosely held stroma showing highly dysplastic features of pleomorphism, altered nucleocytoplasmic ratio, and atypical mitoses (Figure 7). The epithelioid cells were highly undifferentiated and admixed with few spindle-shaped cells with mitotic figures (Figure 7).