Abstract
A 57-year-old male was referred to our department with a chief complaint of a right submandibular mass. Fluorodeoxyglucose-positron emission tomography/computed tomography revealed a lesion with abnormal FDG uptake （SUV max. 9.1） in the right submandibular region. Malignant lymphoma, cervical lymph node metastasis from an unknown primary cancer, and tuberculous lymphadenitis were suspected. Excisional biopsy of the submandibular mass was performed, and the histopathological diagnosis was epithelioid cell granuloma with necrotic tissue. Under the suspicion of tuberculosis, Ziehl–Neelsen staining was added to identify the acid-fast bacteria. Moreover, testing with sputum acid-fast bacteria staining, tuberculin reaction test, and interferon-gamma release assay were performed. The result of Ziehl–Neelsen staining was negative, and no acid-fast bacteria were detected from the sputum. However, the results of the tuberculin reaction test and interferon-gamma release assay were positive. Based on these results, a diagnosis of tuberculous cervical lymphadenitis was made. Therefore, quadruple chemotherapy including isoniazid, rifampicin, pyrazinamide, and ethambutol was started. After one year and two months from the start of the treatment, the course of the patient was uneventful without a new lesion or relapse.
