Int J Clin Exp Pathol 2020;13(11):2907-2915 www.ijcep.com /ISSN:1936-2625/IJCEP0118896 Case Report Collision tumor of carcinoma and lymphoma in the cecum: case report and review of literature Lei Bao*, Xiaoli Feng*, Ting Wang, Fengjuan Xing Department of Pathology, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, People’s Re- public of China. *Equal contributors. Received July 25, 2020; Accepted October 23, 2020; Epub November 1, 2020; Published November 15, 2020 Abstract: Collision tumors that occur in the gastrointestinal tract, especially the intestine, are rare, and collisions of carcinoma and lymphoma are even more rare. We report a case of collision tumor with adenocarcinoma and non- Hodgkin’s diffuse large B-cell lymphoma in the cecum of an elderly male patient. Literature was reviewed to explore the clinicopathologic features, differential diagnosis, treatment, and prognosis of collision tumors with carcinoma and lymphoma involving the gastrointestinal tract, to enhance the understanding of this rare tumor, and improve diagnosis and treatment. Keywords: Collision tumor, diffuse large B-cell, lymphoma, carcinoma, gastrointestinal tract Introduction lymphoma from 1969 to now were found the in PubMed database. Diagnosis and treatment Collision tumor is a rare occurrence where two are discussed. different tumors occur in the same organ [1]. Case report Adenocarcinoma is the most common malig- nant tumor of the gastrointestinal tract, while A 77-year-old man presented to the outpatient lymphoma is relatively rare and accounts for department of Gastrointestinal Surgery of the only 1%-4% of all malignant tumors of the gas- Affiliated Yantai Yuhuangding Hospital of Qing- trointestinal tract [2]. A collision tumor with dao University with right lower quadrant pain both components is extremely rare, especially for more than 3 months. There was no obvious in the intestine [1, 3]. inducement for the patient to have persistent moderate blunt pain in the right abdomen, and The earliest such tumor that we can find was radiation pain in the right waist, which had the collision of adenocarcinoma and pleomor- nothing to do with body position. The patient phic malignant lymphoma reported by Coppola had intermittent episodes with these above et al. in 1969 [1]. In recent years, a collision of symptoms, and had 1 stool/day, yellow and adenocarcinoma with low-grade lymphoma in watery. The patient denied symptoms such as the intestine, and collision of lymphoepithelioid nausea, vomiting, belching, bloating, loss of carcinoma with low-grade lymphoma in the appetite, dizziness, or fatigue. Diet and sleep stomach have been reported occasionally [3, were acceptable, and there was no obvious 4]. The latest report was three years ago. The change in weight. Physical examination reve- treatment of collision tumors is mainly surgical aled abdominal distension, soft abdominal mu- resection combined with radiotherapy and che- scles, and no tenderness or rebound tender- motherapy [5]. ness. CT showed that the intestinal wall of the ascending colon was irregularly thickened and Here we report a case of collision tumor in the rough. Enhanced scan showed obvious enhan- cecum, composed of adenocarcinoma and cement. A mass of soft tissue density shadow non-Hodgkin’s diffuse large B-cell lymphoma. with a cross-section of about 5.5×3.9 cm was 22 cases of collision tumor of carcinoma and seen around it, and the enhanced scan show- Collision tumor of carcinoma and lymphoma cinoma of the colon, which invaded the subserous layer, and an intravascular cancer embolus could be seen locally. The other component was dis- tributed from the subserous layer to the serosa. Microsco- pically, the cells with medium to large size and relatively uni- form morphology grew diffuse- ly, with frequent mitosis and obvious cell atypia (Figure 2). Immunohistochemistry show- ed that the cells were positive Figure 1. CT showed that the intestinal wall of the ascending colon was for CD20, bcl-6, MUM-1, and irregularly thickened and rough, and the enhanced scan showed obvious bcl-2 (Figure 3), and about enhancement. A mass of soft tissue density shadow with a cross-section 10% weakly positive for c-myc. of about 5.5×3.9 cm was seen around it, and the enhanced scan showed Ki67 proliferation index was enhancement. about 80%. Cells were nega- tive for CD10, CD3, and cyclin ed enhancement (Figure 1). Blood cell count D1. In situ hybridization showed EBER was ne- showed that the lymphocyte percentage was gative. IgH gene rearrangement study showed 14.1% (normal threshold was 20-50%), the that the B-cell rearrangement was positive absolute value of lymphocytes was 0.89× (PCR+ Fragment Analysis) (Table 1 and Figure 10^9/L (normal threshold was 1.1-3.2×10^9/ 4). The final diagnosis was non-Hodgkin’s dif- L), and the absolute value of monocytes was fuse large B-cell lymphoma (non-germinal cen- 0.61×10^9/L (normal threshold was 0.1-0.6× tral origin). No carcinoma metastasis or lym- 10^9/L). Remaining indicators were in the nor- phoma involvement were found in 14 mesen- mal range. The patient underwent a right he- teric lymph nodes. micolectomy, followed by chemotherapy for dif- fuse large B-cell lymphoma lymphoma. The pa- Discussion tient was followed up for 4 months without recurrence or metastasis. Collision tumors of carcinoma and lymphoma in the gastrointestinal tract are extremely rare, Pathologic findings especially in the intestine [4]. Through the an- alysis of this case and literature review (see Received in formalin was a section of intestine Table 2 for specific details of all cases) [1-21], it with omentum (part of ileum, cecum, and part was found that this type of tumor mostly occurs of ascending colon). The lengths of the three in middle-aged and elderly men (male:female portions were respectively 4 cm, 6 cm, and 13 =10.5:1, with an average age of 66 years). All cm; and the circumferences were 5 cm, 6 cm, patients who had tumor in the intestines were and 6 cm. An ulcerative mass with a size of male, and all of them were over 60 years old. 6×5×4 cm was seen on the cecal mucosa ad- Almost all patients were treated for gastroint- jacent to ileocecal valve. The cut surface was estinal symptoms such as abdominal pain, na- gray and soft, fish-like, with a clear boundary. usea, and vomiting. Imaging examination was The appendix was 3 cm long, 0.8 cm in diame- indistinguishable from simple carcinoma or ly- ter, and the volume of the omentum was 17× mphoma. Laboratory tests were also nonspe- 8×2 cm. cific. Microscopy showed that the tumor was com- The tumor in the current case occurred in the posed of two components. They were adjacent ileocecal area. Other instances of this tumor to each other but relatively independent, with mostly occurred near the ileocecum, which may almost no cross-growth. One component was be due to the rich and active proliferation of a typical moderately differentiated adenocar- lymphoid tissue there. However, when the tu- 2908 Int J Clin Exp Pathol 2020;13(11):2907-2915 Collision tumor of carcinoma and lymphoma Figure 2. A. Interface of carcinoma and lymphoma (H&E 4×); B. The carcinoma component is moderately differenti- ated adenocarcinoma (H&E 10×); C and D. Medium to large lymphoma cells with relatively uniform morphology grew diffusely, with frequent mitosis and obvious cell atypia (H&E 10× and 40×). Figure 3. A. Cytokeratin is positive in the adenocarcinoma; B. CD20 is diffusely positive in the lymphoma; C and D. bcl-2 and bcl-6 are positive in the lymphoma. 2909 Int J Clin Exp Pathol 2020;13(11):2907-2915 Collision tumor of carcinoma and lymphoma Table 1. The results of gene rearrangement Items Types Results B-cell rearrangement IGH A tube (FR1-JH) + IGH B tube (FR2-JH) + IGH C tube (FR3-JH) + IGK A tube (Vκ-Jκ) + IGK B tube (Vκ-Kde+intron-Kde) + mor occurs in the stomach, unlike adenocarci- due to lack of immune surveillance. The most noma, which tends to occur on the small cur- common carcinoma component of gastric can- vature of the gastric antrum, there is no partic- cer is poorly differentiated adenocarcinoma ularly preferred location. Sometimes the tu- (partly signet ring cell carcinoma), followed by mors are solitary in the entire stomach, and well and moderately differentiated adenocar- sometimes they are multiple. The specimen in cinoma. Very few are lymphoepithelioma-like this case was regarded as ordinary ulcerative carcinoma. Most of the lymphoma compon- cancer. Grossly this type of tumor is an almost ents are MALT, some are DLBCL, and few are ulcerative or irregular mass, and the sections HL. Shotaro et al. believed that Helicobacter are gray-white, soft to medium. It is indistin- pylori (HP) infection was related to the occur- guishable from simple cancer or lymphoma. rence of carcinoma and lymphoma in the colli- sion tumors of the stomach [22]. In such le- Through literature review, we found that the sions, lymphoma may occur before cancer, and histologic morphology of tumors could be rou- HP infection is more closely related to the pro- ghly divided into three types: the most common gnosis of cancer [22]. type is where carcinoma and lymphoma are in the same tumor and the two types of tumor In this case, the pathologist noticed only the cells are mixed and grow crosswise. The sec- moderately differentiated adenocarcinoma and ond is with carcinoma and lymphoma are in the missed the component of lymphoma, and mis- same tumor, but the two tumor types are not takenly thought it was all poorly differentiated mixed and grow relatively independently (our adenocarcinoma.