Recurrent chylous ascites in patient with previous retroperitoneal radiation treatment.

Case report Recurrent chylous ascites in patient with previous retroperitoneal radiation treatment Purva Sharma, Kanishka Chakraborty Medical Oncology/Hematology, East Tennessee State University- Quillen College of Medicine, Johnson City, Tennessee, USA Correspondence to Dr Kanishka Chakraborty; Accepted 14 October 2022 SUMMARY Chylous ascites is the accumulation of lymphatic fluid in the peritoneal cavity due to disruption of lymphatic drainage caused due to obstruction or trauma. We report a man in his 60s who was previously treated for diffuse large B cell lymphoma with radiation to bulky abdominal/mesenteric lymphadenopathy. He was later found to have recurrent chylous ascites several years later, requiring multiple paracentesis. Recurrent lymphoma was ruled out with negative cytology of peritoneal fluid as well as lymph node biopsy with no evidence of malignancy. We believe that the patient had obstruction of lymphatic drainage due to previous radiation therapy causing fibrosis. The patient underwent lymphangiography which did not visualise the central lymphatic duct within the abdomen raising suspicion for obstruction of the ducts secondary to previous radiation. BACKGROUND Chylous ascites is a rare condition usually associated with liver cirrhosis or malignancy. Development of chylous ascites postradiation treatment is rare but has been reported in literature. We describe an interesting case of a patient with diffuse large B- cell lymphoma who was treated with chemotherapy and involved field radiotherapy to bulky abdominal lymphadenopathy, and later developed recurrent chylous ascites several years later, thought to be secondary to previous radiation to retroperitoneum causing fibrosis and obstruction of the lymphatic ducts. CASE PRESENTATION © BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ. To cite: Sharma P, Chakraborty K. BMJ Case Rep 2022;15:e248116. doi:10.1136/bcr-2021248116 A man in his 60s presented with abdominal discomfort, increasing distension and constipation ongoing for a month. Symptoms were progressively worsening and now associated with significant fatigue and poor appetite. The patient’s medical history is significant for diagnosis of diffuse large B-cell lymphoma more than 5 years ago. The patient had stage IIB disease with bulk of disease in the retroperitoneal and mesenteric lymph nodes. Molecular studies revealed t(14;18) suggestive of transformation from underlying follicular lymphoma but no evidence of master regulator of cell cycle entry and proliferative metabolism/B- cell lymphoma 6 rearrangement. The patient was treated with chemotherapy with rituximab, cyclophosphamide, doxorubicin, oncovin, prednisone, with initial plans for total of six cycles. Treatment course was complicated by significant cytopenia requiring prolonged hospitalisation for pneumonia and renal failure after four cycles of chemotherapy. Clinical decision was made to discontinue further chemotherapy. He received involved field radiation therapy to the abdominal and retroperitoneal lymph node regions over 32 calendar days with total dose of 40.0 Gy delivered to the involved region in 20 fractions of 2.0 Gy daily. The patient had reasonably good tolerance to radiation treatment with periodic nausea that was treated with antiemetics. In addition, the patient has no known history of coronary artery disease, chronic lung disease or liver disease. INVESTIGATIONS Given this new presentation, systemic imaging was obtained which revealed large volume abdomino- pelvic ascites and few mesenteric lymph nodes (figure 1). Paracentesis was done with removal of 2.5 L of chylous fluid, cytology was negative for malignancy. Positron emission tomography/ computed tomography scan showed hypermetabolic mesenteric lymph node 2.3 cm with standardized uptake value 12.7 along with a couple of other non- hypermetabolic abdominal lymph nodes. The patient underwent laparoscopic biopsy of the mesenteric lymph node which was negative for malignancy. He also simultaneously underwent drainage of 3.6 L of reaccumulated chylous ascitic fluid. The patient had yet another paracentesis and drainage of 5 L of milky ascitic fluid 10 weeks later. Further analysis of ascitic fluid showed elevated triglycerides >2000 mg/dL. Serum-ascites albumin gradient was 1.0 g/dL. Amylase <10, elevated cell count of 745 /μL with 37% lymphocytes. Ascitic fluid culture was negative for infection. DIFFERENTIAL DIAGNOSIS Chylous ascites is an uncommon condition with an incidence of 1 in 50 000–1 in 100 000 hospital admissions.1 Chylous ascites is a term used to describe ascitic chyle which is a milky fluid with high content of triglycerides. The common causes of chylous ascites include primary disorders of the lymphatic system, infections such as tuberculosis and liver cirrhosis. Malignancy is the most common cause in adults among which lymphoma accounts for at least one- third of the cases.2 Several other benign and malignant tumours can present in the retroperitoneum. Common benign tumours include schwannomas, neurofibromas and paragangliomas. Malignant tumours include soft tissue sarcomas, commonly liposarcoma and leiomyosarcoma, angiosarcoma and gastrointestinal stromal tumour. Immunohistochemical markers play an important role in distinguishing the sarcomas.3 Other malignancies Sharma P, Chakraborty K. BMJ Case Rep 2022;15:e248116. doi:10.1136/bcr-2021-248116 1 Case report Figure 2 Lymphangiography demonstrates normal bilateral lymphatic channels with uptake of lipoidal dye. Figure 1 Pretreatment CT scan showing significant ascitic fluid accumulation. include carcinomas such as primary mucinous neoplasms of the retroperitoneum and disseminated carcinomas originating from primary colon, ovarian, pancreatic or testicular malignancies. Given the anatomical location, these tumours are often present in close relation to important vascular structures which pose therapeutic challenges.4 Correct diagnosis using image-guided retroperitoneal biopsy is important for determining the treatment approach.5 Few less common causes are retroperitoneal fibrosis and post- radiation treatment of retroperitoneum.6 The primary pathophysiology of accumulation of chylous fluid is the obstruction of lymphatic flow from the abdomen to the cisterna chili which then causes increased pressure within the lymphatic system and subsequent extravasation of the lymph and development of chylous ascites.7 8 In malignancy-associated conditions, the obstruction is caused by tumour infiltrating and blocking the lymphatic system. Similarly postradiation treatment fibrosis causes obstruction and blockage of the ducts.9 In our patient, there was no primary malignancy causing blockage of the lymphatic ducts, however, he did receive radiation therapy in the past. So we postulate that radiation-induced fibrosis of the lymphatic channels caused obstruction and subsequent extravasation of the c (...truncated)