Cytomegalovirus (CMV) can cause a broad range of diseases, with severity depending on immune status, comorbidities, and age. Initial CMV infection usually occurs in childhood and is typically asymptomatic, leading to lifelong latency. In immunocompromised patients, CMV can affect multiple organs, but salivary gland infections are rare. This study presents a case of a 66-year-old woman with B-cell acute lymphoblastic leukemia who developed swelling and pain in the right preauricular region during pre-transplant consolidation therapy. Despite a recent bone marrow biopsy indicating morphological remission and a flow cytometry analysis detecting only 0.04 % B lymphoblasts, she exhibited these symptoms. A CT scan revealed enlargement, hyperdensity, and enhancement of the right parotid glands, with accompanying subcutaneous edema. A biopsy of the right parotid gland showed a dense interstitial lymphoplasmacytic infiltrate with numerous Cowdry bodies and smaller granular cytoplasmic inclusions, all testing positive for CMV immunohistochemistry. The findings confirm the diagnosis of CMV sialadenitis in an immunocompromised patient. This case underscores the importance of considering CMV infections in similar clinical scenarios, particularly in patients with compromised immune systems.