A Case of Malignant Colorectal Lymphoma which Spontaneously Regressed
- 1. Department of Gastroenterology, NTT Medical Center, Japan
- 2. Department of Pathology, Dokkyo Medical University, Japan
Citation
Tsunashima H, Nonaka K, Ban S (2016) A Case of Malignant Colorectal Lymphoma which Spontaneously Regressed. Ann Clin Pathol 4(4): 1078.
Keywords
• Lymphoma
• Spontaneously regressed
• Confocal
INTRODUCTION
Reportedly, malignant colorectal lymphoma accounts for 6-12% of cases of malignant lymphoma arising from the digestive tract, and 0.4% of malignant colorectal tumors [1], being relatively rare. We encountered a very rare case of malignant colorectal lymphoma which spontaneously regressed endoscopically, and confocal laser endomicroscopy (CLE] could also be applied to it. The patient was a 70-year-old male who was fecal occult blood-positive and underwent colonoscopy. An ulcerative lesion accompanied by raised area of 20 mm in diameter (Figure 1a) was performed using a probe-based CLE (GastroFlex UHD, Cellvizio; Mauna Kea Technologies, Paris, France]. On CLE, the gland structure had been lost, and small cells were densely present (Figure 1b). Since they were very similar to the CLE findings of duodenal follicular lymphoma and gastric MALT lymphoma previously reported by us [2,3] histological examination was performed with a suspicion of malignant colorectal lymphoma. On histological examination, densely proliferating tumor cells containing a middle-large-sized oval nucleus appearing relatively homogenous were observed (Figure 1c).
On immune staining, the findings were CD79a+, CD20+, CD10+, BCL-, BCL6+, CD3-, CD5-, and cyclin D1-, not contradicting the features of B-cell lymphoma. The Ki-67-positive rate was higher than 50%. Based on PET-CT and bone marrow findings, the patient was diagnosed as stage II B-cell lymphoma. To judge the effect of chemotherapy, a colonoscopy was performed one month after the endoscopy. The morphology and size of the sigmoid colon lesion had markedly changed and shrank, and it was difficult to be diagnosed as malignant lymphoma on histopathological examination of a biopsy specimen. On colonoscopy 3 months after the first examination, the sigmoid colon lesion had completely regressed (Figure 2a), only normal colorectal gland structures were observed (Figure 2b), and no finding suggesting malignant lymphoma was noted on histological examination (Figure 2c). Based on consultation with the patient, careful course observation was selected.