Schwannoma Mimicking Neck Nodal Metastasis on F-18 FDG PET/CT in Cervical Cancer: A Case Report with a Multimodal Approach

초록

Background: In oncologic patients, hypermetabolic neck lesions identified on F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) are often assumed to indicate nodal metastasis, especially in advanced disease. However, benign tumors such as schwannomas can also demonstrate avid F-18 FDG uptake, potentially leading to false-positive nodal staging and unwarranted assumptions of metastatic disease. Case Presentation: An 85-year-old woman with advanced uterine cervical cancer (FIGO stage IIB) underwent F-18 FDG PET/CT for staging purposes. Alongside intense uptake in the primary tumor, a hypermetabolic mass was incidentally identified in the left neck, raising concerns about nodal metastasis. Further imaging, including MRI and high-resolution ultrasonography (US), suggested a non-nodal origin, and US-guided core needle biopsy confirmed the diagnosis of a schwannoma, with histopathologic examination demonstrating characteristic Antoni A and B areas with diffuse S-100 positivity. Because the patient was elderly and repeatedly declined aggressive treatment, management was ultimately limited to symptom-directed palliative radiotherapy. Although tissue confirmation did not directly alter the delivered treatment strategy, it clarified the staging and prevented the neck lesion from being misclassified as metastatic disease. Conclusions: This case underscores that not all hypermetabolic neck lesions detected on F-18 FDG PET/CT in oncologic patients indicate metastatic lymphadenopathy. A multimodal imaging approach combined with minimally invasive tissue sampling can provide critical diagnostic clarification, particularly when PET/CT findings might otherwise lead to unsupported nodal upstaging or misguided assumptions in treatment planning.

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