IgG4-related prostate inflammation easily misdiagnosed: Review
Prostate inflammation rare, misdiagnosed manifestation of IgG4-RD
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IgG4-related prostatitis — an inflammation of the prostate caused by IgG4-related disease (IgG4-RD) — can be easily mistaken for an enlarged prostate or prostate cancer, making diagnosis challenging, according to a systematic review of published cases to date.
Still, data suggested that most men with IgG4-related prostatitis respond well to standard first-line glucocorticoids, a type of anti-inflammatory and immunosuppressive treatment.
“While treatment outcomes are generally favourable, vigilance for relapse and malignancy is warranted,” the researchers wrote.
The study, “IgG4-related prostatitis: expanding the spectrum of IgG4-related disease. A systematic review,” was published in Clinical and Experimental Rheumatology.
IgG4-RD is characterized by the formation of immune cell clumps, mainly composed of B-cells that produce the antibody IgG4, which cause long-lasting inflammation and the formation of tumor-like masses or tissue enlargement. The disease “may affect virtually any organ system,” the researchers wrote. This can result in a wide range of symptoms.
A recent development
“Prostatic involvement is uncommon and has only recently been recognised as part of the IgG4-RD spectrum,” the researchers wrote. “Consequently, current knowledge is largely derived from isolated case reports and small case series.”
IgG4-related prostatitis can resemble an enlarged prostate (benign prostatic hyperplasia) or prostate cancer, so it is often overlooked and difficult for doctors to diagnose.
To better understand how the disease develops, how doctors diagnose it, how it is treated, and the outcomes patients experience, a team led by researchers in Romania conducted a systematic review of IgG4-related prostatitis studies published through mid-February 2025.
Forty-nine studies, describing 66 cases, were included in the final analysis. Patients’ median age at presentation was 64 (range, 20-82), which the researchers said suggests “that IgG4-related prostatitis predominantly affects older men.”
Median disease duration was 18 months (about 1.5 years), but ranged from one month to 96 months (eight years). More than half of the patients (57.8%) had multiple organs involved, while 6.2% had disease limited to the prostate.
Most patients had higher-than-normal IgG4 levels in the blood, and a greater number of organs involved was significantly associated with higher IgG4 levels. Prostate-specific antigen (PSA), which can be elevated in prostatic hyperplasia, prostate cancer, or prostatitis, ranged from very low (0.01 nanograms/mL) to very high (180 nanograms/mL).
About half of the men (50.8%) reported at least one prostate-related symptom, while 30.8% had no symptoms, and 18.5% had no information available. The most common symptoms were lower urinary tract symptoms (39.6%), which included problems such as pain while urinating, frequent urination, abdominal pain, and waking up two or more times during the night to urinate.
Benign prostatic hyperplasia was reported in 20% of the men, while 63.1% had no signs of an enlarged prostate; data were missing for 16.9%. Cancer was identified in 18.5% of cases, most commonly prostate adenocarcinoma, the most frequent type of prostate cancer.
A total of 61 men had available information regarding treatment, with glucocorticoids as the most frequently used (69.2% of cases), especially prednisone. Glucocorticoids were used alone or in combination with other immunosuppressive medications. Some men required surgery, most commonly to remove part of the prostate to relieve a blocked urinary tract.
Available data on 53 men showed that about half (50.9%) had a complete response, meaning their symptoms disappeared, while 23 (43.4%) had a partial response, meaning their symptoms improved but did not resolve completely. Three men died (5.7%).
“Complete response was most frequently observed in patients treated with glucocorticoids or by surgical intervention,” the researchers wrote.
Further statistical analyses showed that men with IgG4-related prostatitis and any form of cancer were significantly less likely to achieve complete remission and more likely to die than those without cancer.
The findings show that the diagnosis of IgG4-related prostatitis may be delayed due to its resemblance to both benign prostatic hyperplasia and prostate cancer. In addition, blood tests for IgG4 antibodies and PSA are not reliable enough for diagnosis or monitoring of the condition.
While glucocorticoids remain “the cornerstone of management, with surgical intervention reserved for selected cases,” larger studies are needed to better understand how common this disease is and how it should be treated, the researchers concluded.
