Abstract
Purpose: Lymphoma originated from mucosa associated lymphoid tissue(MALT) is most common in gastrointestinal system, and rarely found in salivary gland, thyroid, bronchus or orbit. We experienced a case of MALT lymphoma which was originated from conjunctiva and involving lower eyelid without metastasis. Methods: A 40-year-old man suffered palpable mass on right lower eyelid without pain. Orbital computed tomographic and ultrasonographic findings showed a conical mass($1.9{\times}1.2{\times}0.9cm$ size) inside lower eyelid. The mass was completely excised under local anesthesia and histopathological examination was followed. Results: Microscopic finding showed a multiple follicular colonization. In the follicle, small lymphocytes and plasma cells differentiated to centrocyte-like cell, monocyte B cell, plasma cell were diffusely infiltrated. Immunophenotyping was preformed on fixed section. The majority of the small cells were immunoreactive for the B cell marker CD20. Based on the typical histological findings supported by immunostaining, the mass was defined as MALT lymphoma. After excision, SPECT, abdominal CT was carried out and there were no evidence of extraorbital disease. Conclusion: Biopsy and pathological examination should be performed in patients who complain palpable mass on lower eyelid because of possibility of MALT lymphoma. Although MALT lymphoma is rarely metastasized, it is necessary to evaluate the extraorbital involvement using SPECT or other radiologic exams. For detecting extraorbital involvement, periodic follow-up examination is need.