A rare case of duodenal-type follicular lymphoma in rectum appearing as hyperplastic polyp with metachronous appearance in duodenum and stomach

Clinicopathological characteristics of duodenal-type follicular lymphoma: A case report

BACKGROUND

Duodenal-type follicular lymphoma (D-FL) is very rare in clinical practice. Since its clinical manifestations are similar to those of intestinal inflammation or polyps, D-FL is prone to misdiagnosis or missed diagnosis.

CASE SUMMARY

Inexperienced clinical physicians are prone to misdiagnosing D-FL as polyps or inflammation, and it should be distin-guished from intense follicular hyperplasia and lymphoma with follicular structure. Immunohistochemistry (IHC) and molecular techniques are required for its clear diagnosis.

CONCLUSION

D-FL mainly occurs in the descending part of the duodenum, but it can also affect the distal small intestine. Endoscopically, the mucosa shows polyp-like proliferation. IHC staining shows that the tumor cells are positive for CD20, CD79α, CD10, Bcl-6, and Bcl-2, and CD21 labeled follcular dendritic cells show a characteristic "duodenal pattern". BCL2/t(14;18) fusion is often present. D-FL has a good prognosis, and its prognosis needs follow-up observation.

Comparison of characteristics between true rectal neuroendocrine tumors and rectal hyperplastic polyps among patients with endoscope-diagnosed rectal neuroendocrine tumors

Background

To explore the white light endoscopy and endoscopic ultrasonography (EUS) features of rectal hyperplastic polyps (rHP) misdiagnosed as rectal neuroendocrine neoplasms (rNENs). In rNENs with a diameter of 5-10 mm, the endoscopic findings are not typical and some of them are similar to rHP, so it is not uncommon to misdiagnose rNENs as rHP. However, misdiagnosis of rHP as rNENs has not been reported in the literature, which can alert clinicians to the existence of this possibility and avoid over-treatment.

Methods

We collected 245 cases of rectal submucosal tumor (SMT) diagnosed by endoscopy in our hospital from January 2015 to December 2020 and 103 patients with suspected rNENs identified through endoscopy. A retrospective analysis was conducted of the shape, color, vascular dilatation, and boundary on the surface of the lesion under white light endoscope, and the source, boundary, and echo characteristics of EUS. We also analyzed the endoscopic features of rHP misdiagnosed as rNENs. Endoscopic diagnosis and pathological diagnosis were reviewed by a senior endoscopic expert and pathologist respectively. The counting data were tested and analyzed by χ2 test and Fisher exact probability method.

Results

A total of 103 cases of rNENs were diagnosed by endoscope, among whom 75 cases were confirmed as rNENs (72.8%) and 8 cases as rHP (7.8%) by histopathology. There was no significant difference between rNENs and rHP in terms of gender, age, clinical manifestation, shape and color of lesions, dilatation of blood vessels on the surface, and location of lesions. Meanwhile, there were significant differences in whether the boundary of the lesion was clear under white light endoscopy, and the source, echo, and boundary of the lesion under EUS.

Conclusions

The morphology of some rHP is similar to rNENs under endoscopy. The boundary is clear under white light endoscopy and the source, echo, and boundary under EUS are helpful for the diagnosis of rNENs and rHP.

Duodenal Follicular Lymphoma: Track or Treat?

Duodenal follicular lymphoma (DFL) is a rare variety of non-Hodgkin's lymphoma of the gastrointestinal tract that usually carries a favorable course, recognized as a new entity in 2016. It is usually diagnosed at an early stage located predominantly in the second portion of the duodenum. We report the case of a 74-year-old male patient with epigastric pain in whom gastroscopy revealed white mucosal nodules that were pathologically diagnosed as grade 1-2 DFL. Staging investigations revealed secondary lesions in the spleen and at the base of the tongue together with latero-cervical adenopathy. The tumor was stage IV according to the Lugano staging system. We reviewed the recent (last five years) literature defining the importance of combination therapy in the advanced stage. The patient achieved complete remission of the disease through chemoimmunotherapy following the Rituximab-Bendamustine scheme.