MIDDLE EAR MIXED EPITHELIAL AND NEUROENDOCRINE TUMOR MEMENET STATUS POST MASTOIDECTOMY WITH METASTASIS TO THE LIVER MITCHELL TA, MD, CHRISTIAN HUEBNER, MD, MICHELLE HONDA, MD, JEREMY NGUYEN, MD, FACR, RYAN CRAIG, MD, PHD, NEEL GUPTA, MD, JAGAN GUPTA, MD, AND JOSHUA DIENER ABSTRACT Middle ear, mixed epithelial, and neuroendocrine tumors (MeMeNETs) are particularly rare middle ear tumors whose nature has been subject to much discussion in the literature. We present a case of a 33-year-old man with partial left facial paralysis, hearing loss, otitis, and tinnitus. Imaging via computed tomography (CT) demonstrated a soft tissue mass in the left middle ear and external auditory canal. Frozen section pathologic examination of the mass following mastoidectomy revealed spindle features favoring a neoplastic process. The lesion was found to have both neuroendocrine markers (synaptophysin, chromogranin, and NSE) and epithelial cytokeratin marker (AE1/3), alongside a Ki67 proliferation index of approximately 30%, and was determined to be a MeMeNET. On follow-up status-post mastoidectomy and tumor excision, positron emission tomography and computed tomography (PET/CT) ndings were concerning for recurrent and metastatic disease. Subsequent liver biopsy con rmed metastasis, with repeat PET/CT 3 months later demonstrating uptake concerning for progression of disease in the liver while ruling out recurrent disease in the middle ear.
Figure E
Figure F
pre-operative CT, axial section
post-operative CT, axial section
Figure G
Figure H
FDG-PET/CT, axial sections, and MIP PET
PET/CT Ga-68, axial section, and MIP PET conducted 3 months later
Figure A
Figure B
hematoxylin and eosi
AE1/AE3 (pancytokeratin
IMAGING FINDINGS Figures A-D. Microscopic sections from this middle ear lesion demonstrate tumor cells in an in ltrative but nested growth pattern with occasional glandular di erentiation and neuroendocrine- like nuclear features (“salt and pepper”). The tumor cells express both neuroendocrine markers (synaptophysin, chromogranin, and NSE) and epithelial cytokeratin marker (AE1/AE3). The Ki-67 proliferation index is elevated at ~30%. Figures E-H. E. Opaci cation of the middle ear cavity and relatively homogenous soft tissue mass (red arrow) in the medial external auditory canal with erosion of the incus and demineralization of the stapes (pre- operative CT, axial section).
F. Findings are consistent with a left wall down mastoidectomy. Apparent disruption of the tegmen tympani with absent ossicles and questionable disruption of the labyrinthine segment of the facial nerve and subjacent inner ear structures (post-operative CT, axial section). G. Multiple foci of higher-than-expected radiotracer uptake within the liver, with some larger foci corresponding to areas of hypoattenuation. (FDG-PET/CT, axial sections, and MIP PET). H. Regional uptake overlying the pterygoid likely re ecting posttreatment changes versus residual disease (left), and radiotracer-avid low-attenuation hepatic lesions increased since the prior imaging study (right) (PET/CT Ga-68 Dotatate, axial section, and MIP PET conducted 3 months later).
Figure C
Figure D
Ki-67
synaptophysin
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J LA MED SOC | VOL 177 | FALL 2025
J LA MED SOC | VOL 177 | FALL 2025
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