IgG4-related prostatitis

IgG4-related prostatitis is prostate involvement in men with IgG4-related disease (IgG4-RD), which is an emerging fibroinflammatory disease entity which is characterised (i) by a tendency to mass forming lesions in multiple sites of the body and (ii) by usually a prompt response to steroid therapy.^[1][2]

IgG4-related prostatitis
Low power view of IgG4-related prostatitis. The prostatic stroma shows a dense inflammatory infiltrate and fibrosis (H&E, 100x)
Specialty	Urology/Immunology

Men with IgG4-related prostatitis may also present with manifestations of IgG4-RD at other sites anywhere in the body; involvement of different areas of the body can occur either at the same time (synchronously) or at different periods of time (metachronously).^[3]

Presentation

Several case studies on IgG4-related prostatitis have been reported. Patients have been noted to commonly present with lower urinary tract symptoms such as dysuria, pollakisuria, urinary urgency, and a feeling of incomplete emptying.^[4][5] The clinical presentation is similar to that in benign prostatic hyperplasia or chronic prostatitis, although pain, as occurs in CP/CPPS, does not usually appear to be significant.^{[citation needed]}

Histology

The diagnosis of IgG4-related prostatitis could be made from histological examination if prostate biopsy or surgery has been performed.^[6] The hallmark histopathological features of established IgG4-related disease are storiform fibrosis, a dense lymphoplasmacytic (lymphocytes and plasma cells) infiltrate rich in IgG4-positive plasma cells, and obliterative phlebitis.^[7]

However, identification depends on whether or not urologists and pathologists are aware of IgG4-related prostatitis/disease, as special immunostaining is required to identify the characteristic IgG4-positive plasma cells infiltration in prostatic tissue.^[3]

Diagnosis

Men with IgG4-related prostatitis may have similar findings to those that are frequently, but not always, seen in other organ manifestations of IgG4-related disease, such as elevated blood levels of IgG4, IgE and eosinophils.^{[citation needed]}

FDG-PET scans have been reported to be useful as a diagnostic modality for detecting IgG4-related prostatitis in men with IgG4-RD.^[6][8]

Treatment

IgG4-related disease responds well, and often dramatically, to glucocorticoid therapy, provided that advanced fibrotic lesions have not resulted in irreversible damage, and this has included resolution of radiologic findings.^[1] Men given glucocorticoids to treat IgG4-related disease at other anatomical sites sometimes report relief of their lower urinary tract symptoms, suggesting that IgG4-related prostatitis may be underdiagnosed.^[6]

Cases are however likely to get misdiagnosed as benign prostatic hyperplasia and to get treated alternatively with medications such as alpha blockers. The efficacy of alpha blockers in IgG4-related prostatitis remains unclear.^[3]

See also

• IgG4-related disease