Mucosa-associated lymphoid tissue lymphoma of the transverse colon: a case report

Abstract

We herein present a case of a 75-year-old female with mucosa-associated lymphoid tissue (MALT) lymphoma of the transverse colon with the stage IE (Ann Arbor classification). Colonoscopy revealed the tumor's appearance as a IIa plus II c-like early colon cancer as defined according to the macroscopic classification of the Japanese Research Society for Cancer of Colon, Rectum and Anus, measuring less than 2 cm in diameter. Histologically, the tumor was diagnosed as MALT lymphoma because of the presence of lymphoepithelial lesions consisting of diffuse proliferation of atypical lymphocytes and glandular destruction. The majority of these lymphocytes immunohistochemically stained for the B-lymphocyte marker. The patient first underwent H pylori eradication therapy with Lansap. However, the tumor size gradually increased over the next 4 mo and the patient eventually underwent surgical resection. The operative procedure included a partial colectomy with dissection of the paracolic lymph nodes. The tumor measured 45 mm multiply 30 mm in diameter and histological examination showed that the lymphoma cells had infiltrated the muscle layer of the colon without nodal involvement. The patient has had no recurrence postoperatively without any chemotherapy.

Figure 1

Colonofiberscopy showing the tumor’s appearance as a IIa plus IIc-like early colon cancer.

Figure 2

Biopsy specimens histologically showing diffuse proliferation of atypical small lymphocytes in the mucosal layer (A: x 40 magnification, HE) and glandular destruction (B: x 200 magnification, HE). These lymphocytes immunohistochemically showing diffusely positive staining for L-26 (C; x 200 magnification, ABC method).

Figure 3

Barium enema showing a flat and well-circumscribed tumor in the transverse colon (arrows).

Figure 4

Resected specimens showing a flat-elevated tumor with slight depression, measuring 45 mm x 30 mm in diameter.

Figure 5

The lymphoma cells mainly infiltrated into the mucosal and submucosal layers, and partly infiltrated into the muscular layer of the colon (x 20 magnification, HE).