A Rare Presentation of Follicular Lymphoma: Cerebellar Involvement, Successfully Treated with a Combination of Radiotherapy and Chemotherapy
A 57-year-old male patient was referred to the Department of Internal Medicine with complaints of dizziness, dyspnea and respiratory distress when conducting daytime activities. The patient also had unexplained fever over 38℃, sweating and loss of several kilograms in 5-months, which are B symptoms of lymphomas. A plain chest radiography revealed massive bilateral pleural effusion and the thoracentesis fluid represented chylothorax. Computed tomography of the thorax, abdomen and pelvic areas showed bilaterally enlarged multiple conglomerated lymph nodes in the anterior and posterior cervical, supraclavicular, mediastinal, axillary, paraaortic, and inguinal regions. A biopsy of the supraclavicular lymph node revealed grade 2 follicular lymphoma (). The tumor cells stained positive for CD20, CD10, bcl-2, and bcl-6, which is concordant with the B-germinal center cell phenotype. A bone marrow biopsy showed paratrabecular lymphoid infiltration of the B-cell phenotype, which is also consistent with follicular lymphoma infiltration. Based on these findings, the case was classified as stage IV-B disease according to the American Joint Committee on Cancer (AJCC) staging []. Therefore, according to our institutional chemotherapy regimen for B-cell lymphomas including follicular lymphoma, we administered six courses of rituximab-based cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP) chemotherapy. The patient achieved complete response according to the Response Evaluation Criteria in Solid Tumors (RECIST) criteria [] and was followed up regularly every three months for one year, until he applied again with complaints of painless left cervical swelling, dizziness and disequilibrium progressing over a six-week period. He did not experience any contributing symptoms such as vomiting, headache or fever. His physical examination, including neurological and ear systems and vital signs, were inconclusive. Plasma levels of the metabolic parameters including fasting glucose, serum electrolytes and liver and renal function tests were within normal ranges. F-18 fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography revealed a right cerebellar diffuse intensity and left supraclavicular lymph nodes with high maximum standardized uptake value (SUV max) uptake levels of 11.3 and 12.3, respectively (). Moreover, lesser degrees of FDG uptake were detected in inferior cervical lymph nodes, the right mastoid antrum and left supraspinatus muscle regions. Excisional biopsy of one of the left cervical lymph nodes showed grade 2 follicular lymphoma as previously described. These clinical and pathological findings were consistent with relapse of the primary disease. Brain magnetic resonance imaging showed a homogeneously-contrasted lesion, with a maximum diameter of 1.5 cm and isointense appearence of gray matter, involving the dural surface completely on posterior, inferior, and lateral regions of the right cerebellum. Internal contours of the lesion were rough and extended into the cerebellar sulcus. There were also milimetric nonspecific gliotic focuses on both areas of frontoparietal subcortical white matter on the magnetic resonance image (). Taken together, these findings led to a diagnosis of concurrent dural and lepto-meningeal involvement. Therefore, a second-line chemotherapy regimen consisting of 350 mg/m2 rituximab on day 1, 20 mg/m2 fludarabine on days 1 to 3 and 240 mg/m2 cyclophosphamide on days 1 to 3 was started. Whole brain radiotherapy was sequentially administered at a dose of 300 cGy and was scheduled for 10×300 cGy. During the first-year follow-up period, the patient's symptoms and complaints were completely resolved and this case was assessed as a complete response according to the RECIST criteria [].