Clin Endosc.  2017 Sep;50(5):500-503. 10.5946/ce.2016.157.

Twin Rectal Tonsils Mimicking Carcinoid or Mucosa-Associated Lymphoid Tissue Lymphoma

• Takehara M
• Muguruma N
• Kitamura S
• Kimura T
• Okamoto K
• Miyamoto H
• Bando Y
• Takayama T

• KMID: 2394752
• DOI: http://doi.org/10.5946/ce.2016.157

Abstract

The rectal tonsil is a rare polypoid lesion exclusively found in the rectum and is considered a reactive proliferation of the lymphoid tissue. Although this lesion is benign, we recommend that it should be differentiated from carcinoid or polypoid type of mucosa-associated lymphoid tissue lymphomas, based on gross findings. In this case report, we describe a case of rectal lesions with a unique appearance in a 41-year-old man. Colonoscopy revealed two 5-mm-sized nodules located opposite from each other on the left and right sides of the lower rectum. Endoscopic mucosal resection was conducted. Histopathologically, both lesions were mainly located in the submucosa and consisted of prominent lymphoid follicles with germinal centers of various sizes. No immunoreactivity of Bcl-2 was seen in the germinal centers. Immunohistochemical staining for kappa and lambda light chains revealed a polyclonal pattern. Therefore, these lesions were diagnosed as rectal tonsils.

Keyword

Lymphoid hyperplasia; Rectal neoplasia; Submucosal tumor; Endoscopic procedure; Histopathology

MeSH Terms

Adult
Carcinoid Tumor*
Colonoscopy
Germinal Center
Humans
Lymphoid Tissue
Lymphoma, B-Cell, Marginal Zone*
Palatine Tonsil*
Rectum
Twins*

Figure

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  Fig. 1. Endoscopy revealed two red nodules (5 mm in size) located 15 mm from the anal verge.

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  Fig. 2. Narrow-band imaging with magnification revealed dilated branches of vessels on the mucosal surface. (A) Left lesion, (B) Right lesion. Endoscopic ultrasound showed well-demarcated small hypoechoic areas in the lamina propria. (C) Left lesion, (D) Right lesion.

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  Fig. 3. Histopathological findings of endoscopic mucosal resection specimen. (A) Low power view with hematoxylin and eosin staining (×20). Immunohistochemistry revealed that the cells were negative for (B) bcl-2 (×100) and (C) kappa (×200) and (D) lambda (×200) light chains showed a polyclonal pattern.

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