OBJECTIVE We analyzed open biopsy in diagnosing primary thyroid lymphoma (PTL) and tumor management with compression symptoms and therapy. METHODS We retrospectively studied 24 subjects diagnosed with PTL from December 1997 to June 2010. RESULTS Open biopsy was done in 23 of 24 subjects. Incisional biopsy was done in 14, 13 of whom yielded sufficient materials in the first biopsy. Excisional biopsy was done in the remaining 9, 2 of whom developed permanent recurrent laryngeal nerve palsy after biopsy. The five with airway obstruction underwent incisional biopsy followed by immediate steroid administration of dexamethasone or methylprednisolone. All had histopathologically confirmed diagnosis and airway symptoms were resolved within a few days. Multidisciplinary therapy including chemotherapy, radiotherapy, and surgery was applied in 20 of 24 subjects. Single therapy was done in 4-chemotherapy in 2 and radiotherapy and surgery in 1 each. Overall results were satisfactory, with a 92% 10-year disease-free survival rate and an 86% 10-year overall survival rate based on the Kaplan-Meier method with 46-month median follow up. CONCLUSIONS When diagnosing PTL, especially large tumors spreading into extrathyroid tissue, incisional biopsy is more advantageous in histopathological diagnosis than excisional biopsy due to the lower risk of surgical complications. In a case involving a small intrathyroidal nodule, excisional biopsy is safer and more diagnostically accurate. In an airway obstruction emergency, once a definitive diagnosis is made, steroid administration plus endotracheal intubation, if necessary, for airway management is optimal management. Subjects with stage IE mucosa-associated lymphoid tissue (MALT) lymphomas can be treated with radiotherapy or surgery alone. Those with diffuse large B-cell lymphoma (DLBCL) or greater than stage IE MALT lymphoma, however, should be treated with multidisciplinary therapy because they have a potentially poor outcome.