Acute suppurative thyroiditis and aggressive malignant thyroid tumors: Differences in clinical presentation

Background and Objectives: Aggressive malignant thyroid tumors (AMTT) may mimic the clinical symptoms and signs of acute suppurative thyroiditis (AST) in the early course of the disease process. Our objective was to analyze the clinical features of these two conditions, to assess the best way of early diagnosis, and to propose proper treatment. Methods: We retrospectively reviewed and analyzed the clinical features of 30 patients, who had similar clinical pictures of AST and were managed at Chang Gung Memorial Medical Center in Linkou, Taiwan, during the period from 1983 to 1996. These patients were consequently diagnosed as either AST or AMTT. The data were analyzed by the Mann-Whitney U, chi-square and Fisher's exact tests. Results: Among the 30 patients, 25 patients (Male/Female (M/F) ratio = 9/16) were diagnosed as having AST and 5 (M/F ratio = 1/4) as AMTT. After statistical analysis we concluded that the presence of the following factors, namely, older age at diagnosis (P = 0.0155), history of dysphonia (P = 0.0325), right thyroid lobe involvement (P = 0.0151), large size of lesions (P = 0.0013), presence of anemia (P = 0.0075), and sterile pus cultures from thyroid aspirates (P = 0.0013) were cause to suspect a malignancy if the condition did not improve after antibiotics. Delay in diagnosis and management of AMTT may result in a poor prognosis (P = 0.0082). Conclusion: Due to the high mortality rate of AMTT, we should closely observe the patients with poor prognostic variables of acute thyroiditis. Earlier detection and aggressive surgical intervention for AMTT might improve the outcome.