A 64-year-old male with a 6-month history of right mandibular swelling.
Plain radiography showed a well-defined, osteolytic, multiloculated expansive lesion located in the mandibular horizontal branch.
Computed tomography showed an expansive lesion with cortical bone destruction.
With the provisional diagnosis of probable ameloblastoma, the lesion was resected and biopsied.
A median interpapillary incision was made in the mandible, which showed a bulging surface and thickening due to a carnous tumor of dense consistency surrounding the branch of the inferior dental nerve.
After careful curettage of the bone cavity, the mandible was removed and the mucosa was completed.
There were no postoperative complications.
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Pathological Anatomy Setup consisted of tumoral fragments of about 2x1.5 cm, white-grayish at the cut and of firm consistency.
Several samples were taken that were embedded in paraffin after being fixed in formaldehyde and fixed by routine techniques: sections 4m thick were cut and stained with hematoxylin-eosin.
We proceeded to immunohistochemical study of representative sections using the avidin-biotin peroxidase method, using primary antibodies anti epithelial membrane antigen EMA, (Dakhando M613, USA, 10/500)
The process was performed following the standard protocol, using positive and negative controls.
Fluorescence in situ hybridization (FISH) was performed in 50m thick paraffin sections by means of a double-colored mixer LSI BCR/ABL (VYSIS Inc, USA drug triple filter).
Histologically, the tumor fragments were composed of elongated cells of regular shape and size arranged in interlocked bundles and in beetles structured in " onion bubble".
Cell density and intercellular stroma were variable, with some areas showing myxoid aspect.
Cells arranged in palisade were not observed, neither cellular pleomorphism nor mitoses were observed.
In the periphery of some fragments residual fibers of the mandibular nervous trunk were identified.
With the provisional diagnosis of PIN, examinations were performed.
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Immunohistochemistry showed that tumor cells were strongly positive for EMA and vimentin and negative for S-100 protein, NSE, collagen IV, CD57, smooth muscle a-actin and CD34.
Schwann cells in the beetles were positive for S-100 protein and in the center of the "bulbs" positive axons for anti-neurofilament antigen were identified.
Residual fibers of the dental nerve were positive for S-100 protein, SES and neurofilaments and perineurium positive for AME.
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Fluorescence in situ hybridization revealed a deletion of the long arm of chromosome 22 (22q11) in the nuclei of 75% of tumor cells as well as loss of centromere of chromosome 22.
