Alveolar parenchyma with denuded enlarged (cytomegalic)cells and alveolar hemorrhage.
As so named, CMV causes cytomegaly with both nuclear and overall cell enlargement. Note the intranuclear inclusion with circumferential clearing within the nuclear membrane. Cytoplasmic inclusions can also be found in some viropathic cells (arrow).
CMV (cytomegalovirus), a virus belonging the Herpesviridae family, can produce a wide variety of diseases depending on the age and immune status of the host. For example, CMV can lead to congenital disease if a mother is newly infected during pregnancy. CMV is one of the TORCHES (Toxoplasmosis, Rubella, CMV, Herpes, HIV and Syphilis) organisms that can cross the placenta. Perinatal CMV can be transmitted to the infant in vaginal or cervical secretions or through breast milk during an active infection of the mother.1
In immunocompetent children or adults, CMV infection is usually asymptomatic, but in some cases, may cause mononucleosis syndrome similar to EBV infection with fever, atypical lymphoctes, lymphadenopathy and hepatosplenomegaly. Up to 80% of adults worldwide have been exposed to CMV as evidenced by anti-CMV antibodies in their serum.2
In immunosuppressed individuals, CMV can lead to serious systemic disease. These patients can be divided into two groups: (1) transplant patients of solid organs (liver, heart, kidney) or bone marrow; (2) HIV patients. In solid organ transplants, the CMV may reside in the donor organ. In bone marrow transplants and HIV patients, latent CMV infection is usually reactivated. Interestingly, CMV infection in HIV patients cause retinitis, colitis and rarely pneumonitis. In transplant patients, CMV infection does NOT cause retinitis, but rather, mainly pneumonitis and sometimes colitis.1,2
Diagnosis can be accomplished by PCR assay to detect CMV DNA.
1 Kumar V, Abbas AK, Fausto N. Robbins and Cotran Pathologic Basis of Disease. 7th Ed. Philadelphia, PA: Elsevier; 2005: 754-5.
2 Gladwin M, Trattler B. Clinical Microbiology Made Ridiculously Simple. 4th Ed. Miami, FL: MedMaster; 2009: 274-5.