Solitary juvenile polyp as a cause of elevated faecal calprotectin in an adult

Validation of rapid fecal calprotectin assay using particle enhanced turbidimetric immunoassay for inflammatory bowel disease

Fecal calprotectin (FC) is a promising biomarker for diagnosis and treatment of inflammatory bowel disease, ulcerative colitis (UC), and Crohn's disease. An enzyme immunoassay (EIA) is widely used for FC detection, though the considerable lag time, up to several days, causes clinical management delay. This study was performed to examine the new rapid kit fCAL-turbo, which is based on a particle-enhanced turbidimetric immunoassay (15 min), by comparing FC values with other EIAs (EliA, PhiCal, Bühlmann) and endoscopic scores. Using 94 samples, fCAL-turbo showed strong significant positive correlations with the other kits (Spearman's r = 0.9178-0.9886). Of 74 UC patients, 69 underwent an endoscopy and fCAL-turbo reflected endoscopic activity with a moderate correlation with Mayo endoscopic subscore (MES) (r = 0.6945, others r = 0.6682-0.7013). Receiver operating characteristic analyses based on MES 0 versus 1-3 showed a similar efficacy as compared to the other kits (cut-off and area under the curve: 89.70 µg/g and 0.8592, respectively, others 62.35-138.4 µg/g and 0.8280-0.8611, respectively). Furthermore, multiple regression analysis confirmed that fCAL-turbo results significantly contributed to prediction of MES 0 with a higher t-value as compared to the other biomarkers. fCAL-turbo showed strong correlations with the other kits and also demonstrated excellent performance for predicting endoscopic remission of UC.

Diagnosis and management of a solitary colorectal juvenile polyp in an adult during follow-up for ulcerative colitis: A case report

BACKGROUND

Juvenile polyps are the most common type of polyps in children but are rare in adults. Inflammatory bowel disease (IBD) patients have a similar spectrum of symptoms as patients with juvenile polyps. Both patients with juvenile polyps and those with active IBD have high fecal calprotectin levels. Four cases of children with ulcerative colitis (UC) with solitary juvenile polyps and one case of an adult with UC with juvenile polyposis syndrome have been reported upon diagnosis of UC, while there have been no cases of adults with UC with solitary juvenile polyp reported in the literature.

CASE SUMMARY

A 37-year-old man with a 12-year history of UC was admitted to our clinic because of increased stool frequency. UC was diagnosed at the age of 25. As the lesion was confined to the rectum, sulfasalazine suppositories or mesalazine suppositories were used. The patient was followed in an outpatient clinic, and colonoscopy was performed every one or two years. The latest examination was undertaken three years prior in the presence of proctitis. Recently, the patient complained of three to five bowel movements a day. There was mucus in the stool but no visible blood. Colonoscopy revealed a solitary polyp, about 1.5 cm in diameter, with a short and broad peduncle in the transverse colon surrounded by congestive and edematous mucosa. The patient had no family history of colorectal polyps or cancer. The polyp was successfully removed by endoscopic mucosal resection. Histopathological examination revealed that the polyp was a juvenile polyp without any malignant signs. Immunohistochemical staining for p53 showed wild-type expression and p53 overexpression was not detected. Ki-67 labeling index was 3%.

CONCLUSION

This is the first case of an adult UC patient with a solitary juvenile polyp at the 12-year follow-up. The correlation between juvenile polyps and the activity of IBD needs further study.

Limitations of the determination of faecal calprotectin in patients with ulcerative colitis and inflammatory polyps

INTRODUCTION

Faecal calprotectin is a useful technique for detecting activity in patients with ulcerative colitis. However, there may be high levels due to factors other than the activity of ulcerative colitis. Our aim was to analyse possible false positive results of calprotectin for the activity of ulcerative colitis owing to the presence of inflammatory polyps.

PATIENTS AND METHODS

Retrospective, observational, descriptive study. Data was collected from patients monitored for 2 years in whom a colonoscopy had been requested within 3 months after detecting high calprotectin values (>150μg/g) and before modifying the treatment.

RESULTS

We reviewed 39 patients and in 5 of them, with previous diagnosis of extensive ulcerative colitis, inflammatory polyps were detected. Three patients were on treatment with mesalazine, one with azathioprine and other with infliximab. All of them were asymptomatic and the endoscopy did not show macroscopic activity (endoscopic Mayo score=0) or histological activity. The median values of calprotectin were 422μg/g (IQR: 298-2,408) and they remained elevated in a second measurement. In 4 of the patients the inflammatory polyps were multiple and small in size. The other patient had a polyp measuring 4cm.

DISCUSSION

In clinical practice we can find high faecal calprotectin levels not due to the presence of ulcerative colitis activity, but due to other lesions such as inflammatory polyps. This fact must be taken into account before carrying out relevant changes such as step-up therapy to immunosuppressive drugs or biological drugs in patients with confirmed high calprotectin levels.