Cervical lymph node enlargement as the first and sole manifestation of IgG4-related disease (IgG4-RD) is rare and is often difficult to distinguish from lymphoma. Here, we report a case of a 63-year-old man initially presenting with bilateral posterior neck masses. Ultrasonography revealed multiple matted, ovoid, homogenous, hypoechoic, and enlarged lymph nodes below the right parotid gland. In addition, there was heterogeneous echotexture with small and indistinct hypoechoic nodules over bilateral parotid and submandibular glands which suggested sclerosing sialadenitis. Pathology of the tissues obtained by core needle biopsy revealed reactive hyperplasia, but a diagnosis of lymphoma could not be excluded. Subsequently, excisional biopsy and serological tests were done. The diagnosis of IgG4-RD was confirmed due to marked elevation of serum IgG4 levels and pathological evidence of IgG+ and IgG4+ plasma cell infiltration in the lymph node specimen. The patient's neck masses subsided gradually after 1 week of oral steroid therapy. The differential diagnosis of IgG4-RD should always be considered when sclerosing sialadenitis is presented with cervical lymphadenopathy.