Non-polypoidal, synchronous mantle- cell lymphoma of small intestine: a rare case

Herein is reported the case of a mantle cell lymphoma (MCL) with synchronous double intestinal location. A 74 - year old male presented with mild abdominal pain. CT scan imaging indicated invasion of lateral intestinal cavity by large mass formation. Exploratory laparotomy was performed and two solid extra-mural masses were isolated and excised. Histology revealed non- polypoid double synchronous lymphoma of mantle cell origin, an unusual presentation of the disease.


Background
Mantle cell lymphoma (ICD-O code 9673/3) is a subtype in the wide category of B-cell lymphomas [1,2]. It is a specific type of Non-Hodgkin's lymphomas comprising 3% -5% of all cases [1][2][3]. The histological derivation is from the "naïve" (functionally active but immunologically immature cells) CD5 + B-cells residing in the primary follicles or in the mantle zones of secondary follicles [4]. A translocation between chromosomes 11; 14 takes place, leading to the juxtaposition of the cyclin D1 and the consequent over-expression of the CCND1 gene [5]. Mantle cell lymphoma (MCL) is composed of monomorphous small to medium sized lymphoid cells with irregular nuclei [1,2].
At the time of diagnosis most patients have signs of multiple lymphatic involvement, including spleen, red bone marrow, cervical lymph nodes, liver, and gastrointestinal tract, usually under a condition known as "multiple small intestine polyps" [6][7][8]. MCL cells may also invade the brain and spinal cord [6,8]. Most patients present with stage III to IV of the disease including lymphadenopathy, hepatosplenomegaly while over 50% include bone marrow involvement [1,2,6].

Case report
A 74-year-old Caucasian male Greek patient, presented with mild abdominal pain and a history of recurrent gastrointestinal bleedings over the last few years.
At the time of admission at the hospital his general state was not indicative for an emergent situation. The patient complained for insisting abdominal discomfort, moderate flatulence and anorexia. Physical examination revealed abdominal distension with flat sounds at percussion, moderately decreased intestinal sounds, without signs of localised sensitivity or peritoneal irritation.
An emergency abdominal CT scan revealed a large solid mass invading the left lateral area of the abdominal cavity and distended small bowel helixes (figure 1). There was also indication of partial intestinal obstruction, at the level of sigmoid colon, with imaging of hydroaeric levels and decreased transmission of the contrast agent. Gastroscopy and colonoscopy were also performed, both without confirmation of large bowel and sigmoid colon intraluminal obstruction.    A wide enterectomy of almost 37 cm was performed, with excision of small bowel, mainly ileum, followed by gastrointestinal anastomosis. Frozen section biopsy of the excised specimen was positive for malignancy. A large number of mesenteric lymph nodes were also included in the final biopsy material.
Histology revealed diffuse, full-length, non-specific nodular infiltration of small bowel walls reaching the level of serosa, for both tumoral formations (figures 5, 6,7,8). Identification of cellular populations and immunohistological evaluation revealed a biphasic pattern with lymphocytic collections formed particularly by small lymphocytes mixed with a small population of immunoblasts, positive for Cyclin D1, CD5, CD20, CD35, CD79, CIgG(), and negative for CD3, CD10, CD21, CD23, and CD43. Limited cellular multiplication rate was noted. Plasmocyte populations were also noticed (positive for CD138, MUM-1, CIgG() and negative for CD3 and CD20). Findings were significant for non-Hodgkin lymphoma of B-cell origin with low malignant potential. The tumoral origin is in the marginal cell zone demonstrating plasmocytic differentiation and positive CIgG(k) clonal functions. Furthermore, involvement of 14 mesenteric lymph nodes was confirmed.
The patient's postoperative course was uncomplicated, with immediate mobilisation and normal intestinal functionality. He was discharged from hospital 10 days later in a general good status and after an interval of 22 days he initiated adjuvant chemotherapy (CHOP regiment) administered in a single day every 3 weeks for 6 cycles. In addition to chemotherapy the patient received treatment with monoclonal antibody Rituximab which acts against CD20, a special molecule on the surface of B-cell Non-Hodgkin Lymphomas.

Discussion
Mantle cell lymphoma is an entity of B-cell malignancies, belonging in the non-Hodgkin lymphomas [1,2,6]. Intestinal lymphoma is the most usual presentation of extranodal MCL, presenting under the form of multiple lymphomatous polyposis (MLP). Small intestine (duodenum, jejunum and ileum) is reported to be involved in 15% -30% of GI lymphomas [9,10].
Prognosis for intestinal malignant lymphoma is poor due to its accelerated proliferation and the non-specific clinical presentation of the disease. Most of the patients have advanced stages of the disease at the time of diagnosis, being also delayed by the difficulty in direct visualization of small intestine. Patients with obstructive tumour masses require surgical resection.
The case of extra-luminal augmentation of the tumour is extremely seldom and double synchronous presentation of such masses even rarer. Few cases are reported of synchronous colonic tubular presentations [10,11]. In non intestinal locations, MCL of the pleura and synchronous presentation of pulmonary adenocarcinoma may present [2] and there is also case of metastatic MCL presenting as a prolapsed vaginal mass [12].

Conclusions
Non-polypoid lymphomas of the small bowel can be a rare place of occurrence for mantle cell lymphomas. In such cases of lymphomas presenting as small bowel individual tumors, with single or multiple location, the treatment of choice is surgical resection with appropriate anastomotic procedures. Following surgery, additional treatment with chemotherapy is also proposed, according to the classification of malignancy.

Consent
Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the journal's Editor-in-Chief.