A carcinoid tumor of the middle ear masquerading as a glomus tympanicum presenting with temporal lobe hemorrhage in a 70-year-old woman: Case report and review of the literature.

BACKGROUND: Paragangliomas in the central nervous system account for 0.6% of all head and neck neoplasms, with glomus tympanicum being the most common middle ear tumor. Carcinoid tumors are neuroendocrine tumors, representing less than 1% of neuroendocrine neoplasms in the middle ear. Misdiagnoses have been reported in the literature regarding glomus and carcinoid tumors, however, none have been in the central nervous system or middle ear. CASE DESCRIPTION: A 70-year-old female with a history of left temporal lobe tumor underwent unsuccessful resection due to intraoperative bleeding at an outside institution. However, biopsy prior to aborting the case led to the diagnosis of paraganglioma. Eight years postoperatively, the patient presented at our institution with acute confusion, aphasia, and altered mental status. Imaging revealed a 4cm left temporal intraparenchymal hematoma at the known tumor site with concern for intracranial tumor extension. Surgical resection was performed and previous symptoms resolved. Final pathology revealed a Grade II atypical carcinoid tumor with an unusually high Ki-67 of 50%. CONCLUSIONS: Carcinoid tumors of the middle ear constitute a differential diagnosis for patients presenting with temporal lobe hemorrhage. A combination of immunohistochemical staining with electron microscopy can assist in differentiating the tumor types. This atypical presentation for a carcinoid tumor in the middle ear suggests the need to consider carcinoid as the diagnosis in patients with a middle ear tumor invading into the temporal lobe and causing hemorrhage. These tumors may demonstrate an unusually high Ki-67 rate, in which case they should be treated aggressively.

TU-E-BRA-10: Personalized Utility Function for Radiotherapy Based on Pulmonary Ventilation of Locally Advanced Lung Cancer Patients.

PURPOSE: To develop tailor-made utility functions based on each patient's pulmonary function distribution so that personalized organ-function-based treatment plan is obtained for locally advanced lung cancer patients. METHODS: Five locally advanced lung cancer patients were retrospectively evaluated in the study. Fractional regional ventilation was obtained by performing subtraction of spatially matched and corrected 4DCT images. Histogram of the fraction ventilation values was generated for each patient. The cumulative distribution function (CDF), which represented an inverse relationship with the desired dose to each voxel for function preservation, showed potential as personalized utility function. In order to spare the majority of the volume with pulmonary function, a more aggressive utility function was defined as a piece-wise linear function based on the most frequent fractional ventilation value (peak of the histogram). This utility function was used in the objective function during treatment planning. Conventional objectives and constraints were maintained during the planning process. RESULTS: Both conventional plan and personalized functional plan were classified as satisfactory plans by physician based on conventional dose and dose-volume metrics. However, functional plan successfully spared high ventilation volume based on each patient's unique condition. When spatial function information was included to collect function dose/dose-volume metrics, significant reduction of fV20, fV30 and mean lung dose was achieved by function-based personalized plan with p-value < 0.01. CONCLUSIONS: Organ-function-based radiotherapy has been presented to incorporate patient's pulmonary function in hopes of reducing the risk of complications. Current methods utilize the function information in the same fashion across patients. We took one step further to not only incorporate heterogeneous pulmonary function during treatment planning but also generate personalized utility function based on the function distribution of each patient. AAPM Research Seed Funding Initiative.