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Case of the Week #318
A 50 year old man presented with a right lung tumor, which as biopsied. Grossly, multiple fragments of tumor measured 5 cm in aggregate.
What is your diagnosis?
Ameloblastoma metastasis to lung
Discussion: Immunostains were obtained:
No normal lung tissue was seen in the biopsy. The cells have a benign appearance, arranged as back-to-back elongated nests with peripheral palisading, central loose reticulum, minimal hyperchromatism and rare mitotic activity. The tumor cells were positive for CK AE1/AE3 and p63, and negative for BerEP4 and TTF1. The MIB1 index was low. The referring clinician subsequently reported that the patient had a left mandible tumor resected 10 years ago which was reported as ameloblastoma. There was no histology report, but a recent x-ray of the mandible was obtained, which showed a previous tumor excision site: