Incidental finding of a neuroendocrine neoplasm in a suspected ear canal exostosis

A 55-year-old man was referred to the Department of Otorhinolaryngology with a five-month history of progressive conductive hearing loss associated with a tumor in the external auditory canal. A temporal bone computed tomography (CT) revealed a bony growth covered by a thickened layer of soft tissue compatible with an exostosis. The suspected exostosis was removed and histological examination unexpectedly revealed a well -differentiated neuroendocrine tumor, morphologically and clinically consistent with a primary tumor. Subse-quent investigation found no clinical or imaging evidence of other tumors. There was no focal uptake on 18 F-FDG/PET, whereas a68Ga-DOTATOC PET/CT revealed an isolated focal uptake of gallium at the tumor site. Immunohistochemical staining of the surgical re-resection revealed a tumor with a Ki-67 proliferation index of 1% (NET grade 1). 68Ga-DOTATOC PET-CT scans performed after 3 and 12 months showed no signs of recur-rence. Among the few previously reported primary neuroendocrine tumors in the external ear canal, none had exostosis-like bone growth underneath the skin tumor. Neuroendocrine tumors in the head and neck region are rare and often lack clinical malignant characteristics both in terms of visual appearance and lack of activity on 18F-FDG PET/CT. Histological examination and 68Ga-DOTATOC PET/CT are essential for timely diagnosis.

Automated summary

A 55-year-old man presented with progressive conductive hearing loss and an external auditory canal tumor. After surgical removal, the tumor was unexpectedly identified as a well-differentiated neuroendocrine tumor through histological examination and PET/CT scans. This case is unique in that it had exostosis-like bone growth underneath the tumor, a feature not previously reported.