Viral Cytopathic Changes in Sputum Cytology in a Patient with Known Human Metapneumovirus

Viral cytopathic changes seen in sputum cytology have been described in association with infection by viruses such as cytomegalovirus (CMV), herpes simplex virus (HSV), adenovirus, and even measles. However, viral cytopathic changes due to human metapneumovirus (hMPV) have not yet been well described in cytology. hMPV is a relatively new entity, discovered in 2001. It is known to cause upper and lower respiratory tract infections in children, the elderly, and immunocompromised patients.

We describe the viral cytopathic changes seen in sputum in a 63-year-old male patient with known hMPV. These changes include multinucleation, nuclear enlargement, homogenised nuclei, basophilic nuclear inclusions with perinuclear halos, and small eosinophilic cytoplasmic inclusions.

We aim to raise awareness that hMPV can cause viral cytopathic changes and to describe these cytological features, which have been elucidated in only 1 case report thus far. Distinction from other viruses with similar changes, such as HSV and CMV, is important due to their differing clinical implications.