<scp>CMV</scp> proctitis mimicking a rectal tumor

A 95-year-old male presented with a 3-month history of rectal bleeding associated with pain and weight loss. A rectal mass was palpated on examination. His past medical history is significant for ischaemic heart disease, heart failure, chronic obstructive airways disease, and rheumatoid arthritis on low-dose methotrexate. Sigmoidoscopy revealed a large, infiltrative, non-circumferential tumour with contact bleeding on the left lateral rectal wall (Figs. 1 and 2). Initial biopsies found ulcerated tissue without malignancy. A transanal excisional biopsy subsequently showed CMV inclusion bodies were identified (Fig. 3). He was commenced on valaciclovir following discussions with the infectious diseases physician, with resolution of rectal bleeding and improvement on repeat endoscopic assessment. Cytomegalovirus (CMV) infections are often opportunistic in nature and are associated with tissue invasive disease and post-transplant lymphoproliferative disorder in immunocompromised patients.1 It is often a harbinger of morbidity and mortality for these patients. Although the prevalence of CMV in the general population is about 70%, CMV infections in immunocompetent patients are often asymptomatic, with minimal morbidity associated. The prevalence of CMV infections diagnosed and confirmed via endoscopy in immunocompetent patients is an estimated three in 1000 cases, with 94% of these reported cases involving the colon, with rectal involvement rarely reported.2 CMV proctitis may be classified as (1) primary infections and (2) reactivated CMV infections.3 Patients presenting with mononucleosis-like illness associated with rectal bleeding in the ensuing days to weeks following unprotected anal intercourse are often pathognomonic for primary infections.4 In reactivated CMV proctitis subtypes, these occur in the elderly population with significant comorbidities (e.g. diabetes, inflammatory bowel disease and critical illness) that render a blunted immune response.3 Interestingly, our patient was on low-dose methotrexate, which possesses antiviral activity against CMV infections.5 The pathogenesis of reactivated CMV intestinal infections is postulated to originate from disruption of mucosa or from suppression of natural killer cell function in the setting of sepsis.3, 6 However, there is a paucity of data regarding complex interactions between the incited inflammatory cascade, viral loads, and reactivation stimulus causing CMV disease in immunocompetent patients. Clinical manifestations often vary and may include haematochezia, weight loss, abdominal pain, diarrhoea, and haemorrhage. Endoscopic findings may also vary from mild mucosal inflammation and oedema to cobblestoning and severe ulceration.2 Biopsies around the edges or base of the ulcerated areas are necessary to achieve a diagnosis of CMV infections. Classically, tissue biopsies show inclusion bodies with positive CMV immunohistochemistry staining.7 There remains a dearth of evidence in the utility of antivirals in immunocompetent patients due to the low prevalence of the disease in such a population barring conduction of trials to evaluate efficacy. Given it is often a self-limiting disease, antivirals may not necessarily contribute to improvement in symptoms. The benefits versus risks of toxicity of antivirals should be carefully considered before commencing treatment for patients. CMV proctitis is a rare entity and may mimic a malignant tumour. CMV testing should be considered in high-risk population groups if the initial biopsies return negative for dysplasia or malignancy. Open access publishing facilitated by Monash University, as part of the Wiley - Monash University agreement via the Council of Australian University Librarians.