Lymphoma Meets Refractory Chylothorax:
How the MDT Broke the Dilemma Between Systemic Therapy and Surgical Intervention

This article is a de-identified educational case review. It describes the clinical course of one patient managed at Beijing Arion Cancer Hospital and reflects the team's approach to MDT decision-making when an indolent lymphoma is complicated by refractory chylothorax. It is not medical advice, nor does it guarantee outcomes for other patients. Treatment decisions must be individualized by qualified physicians.

Case Introduction

Follicular lymphoma (FL), the archetypal indolent non-Hodgkin lymphoma (NHL), now has a well-established treatment strategy — but chylothorax arising during its treatment is a rare and stubborn complication.

This patient was a 51-year-old woman who was already stage IV, group B at diagnosis, with extensive nodal involvement and bone marrow infiltration, and a very high tumour burden. While obinutuzumab-based immunochemotherapy produced a clear response, she developed recurrent right-sided chylothorax that repeated thoracentesis and conservative management could not cure. Faced with "tumour control" and "recurrent chylothorax" coexisting, the MDT team had to weigh precisely between continuing systemic therapy and definitive surgical intervention. In the end, thoracoscopic thoracic duct ligation clinically cured the chylothorax and the lymphoma reached complete remission (CR), offering a practical reference for similar cases.

I. Case Overview: Baseline Status and Core Challenges

Baseline Status

A 51-year-old woman presented with more than two months of lumbar soreness, abdominal distension and difficulty passing stool.

PET-CT showed hypermetabolic lymph nodes of varying size in right cervical level V, the bilateral supraclavicular, bilateral axillary and bilateral medial pectoralis minor regions, the mediastinum, bilateral cardiophrenic angles, bilateral posterior crural regions, the portocaval space, the retroperitoneum and the abdominopelvic mesentery; confluent soft-tissue density along the retroperitoneum and both iliac vessel chains, encasing vessels with increased metabolic activity; disordered bowel architecture in the abdomen and pelvis with multiple focal hypermetabolic foci located mainly in the small bowel and uneven mural thickening; an enlarged spleen with heterogeneous increased uptake; and uneven thickening of the anterior wall of the gastric antrum protruding into the lumen with increased metabolic activity (Figure 1).

Pathology: (abdominal mass, left upper para-umbilical region) non-Hodgkin B-cell lymphoma, consistent with FL, grade 1-2.

Immunohistochemistry: CD20 (diffuse +), Bcl-2 (germinal centre +), Ki-67 (+20%), Bcl-6 (germinal centre +), CD10 (germinal centre +), MUM1 (occasional +), CyclinD1 (−), EBER (−).

Staging: FL stage IV, group B (FLIPI-2 high risk). She had night sweats, but no fever and no significant weight loss among the B symptoms.

Three Interlocking Core Challenges

First, an extremely high tumour burden — systemic treatment could not wait. At diagnosis there were multiple abdominopelvic and retroperitoneal masses, disordered bowel architecture and uneven small-bowel mural thickening, together with lumbar soreness, abdominal distension and difficulty passing stool — evidence that the tumour was already causing definite organ compression and functional impairment. Effective chemotherapy needed to start as soon as possible to reduce the tumour burden.

Second, a poor baseline state that limited treatment tolerance. At initial treatment she had hypoproteinaemia with pleural, peritoneal and pericardial effusions. Her nutritional status and physiological reserve were both suboptimal, posing a potential threat to her tolerance of chemotherapy.

Third, recurrent treatment-related chylothorax, creating a vicious circle of "treatment → complication → more treatment". Before cycle 3 the patient developed a cough, and repeat chest CT showed a marked increase in pleural fluid. Thoracentesis and pleural fluid studies confirmed chylothorax of non-tumour origin. Thereafter she required repeated thoracentesis drainage at roughly 800 ml per day, which did not resolve spontaneously and seriously disrupted the subsequent chemotherapy schedule and her quality of life.

II. Decision-Making: MDT Core Analysis and Strategy Deliberation

MDT Team Composition

The multidisciplinary consultation involved specialists from the lymphoma centre, thoracic surgery, radiology, pathology and nutrition, covering the full spectrum of lymphoma systemic therapy, thoracic surgical intervention, imaging assessment, pathological differential diagnosis and nutritional support.

Choosing the Lymphoma Systemic Regimen

Option A — standard therapy: The standard first-line regimen for FL stage IV group B is obinutuzumab (G, an anti-CD20 antibody) combined with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone), which markedly improves prognosis. However, the patient declined PICC placement at initial treatment, so cycle 1 was adjusted to G-CVP with cyclophosphamide divided over two days, and from cycle 2 the standard G-CHOP regimen was used.

Option B — dose reduction or delayed chemotherapy: Given the large protein loss caused by chylothorax and the trauma of repeated drainage, some held that chemotherapy should be paused. The MDT team judged, however, that although the chylothorax was not caused by direct tumour invasion, eliminating the tumour would unquestionably help cure it — so completely interrupting anti-tumour therapy was not advisable.

Chylothorax Management: A Stepwise Escalation

Option A — conservative management: Including closed thoracic drainage, a low-fat or medium-chain triglyceride diet, nutritional support and drugs such as octreotide. This approach is minimally invasive, but in this patient repeated thoracentesis still produced persistent large-volume chyle leakage (800 ml/day), indicating severe thoracic duct injury or abnormal lymphatic permeability and a low likelihood of spontaneous resolution.

Option B — thoracoscopic thoracic duct ligation: Indicated for high-output chylothorax after conservative treatment fails. The literature reports success rates above 90% for thoracic duct ligation in traumatic chylothorax[1], but its efficacy in non-traumatic — especially malignancy-associated — chylothorax remains unclear[2]. Surgical risks include persistent chyle leak, loculated chylothorax, pneumonia and injury to surrounding structures[3], with a mortality of about 3%[4].

Option C — lymphatic embolisation: This requires a clearly identified leak point on lymphangiography. In this case lymphangiography showed no definite extravasation of lipiodol, so the effect of embolisation could not be guaranteed and it was not prioritised.

Sequencing Chemotherapy and Chylothorax Treatment

The central controversy was whether chemotherapy should be paused or modified when chylothorax is poorly controlled. The MDT team judged — from the objective disease course, the timing of onset, the pleural fluid studies and the treatment response — that the patient was responding well to treatment for the lymphoma (abdominal distension and pain clearly relieved, lymph nodes shrinking). Provided drainage was adequate and nutrition assured, G-CHOP could continue as planned while the indications for surgical intervention were actively assessed.

Forming the Final Decision

After several MDT discussions, a staged consensus was reached:

Stage one: With closed thoracic drainage controlling the chylothorax, complete the remaining G-CHOP chemotherapy while intensifying nutritional support (low-fat diet, albumin and fat-soluble vitamin supplementation) and closely monitoring pleural fluid volume and the patient's general condition.

Stage two: If the chylothorax recurred despite conservative management, assess surgical intervention. Indications included an adult chyle output exceeding 1.5 L per day[5] (this patient did not reach that threshold, but drainage had continued for more than two weeks and was disrupting treatment), deteriorating nutritional status, and failure of conservative treatment[6].

Stage three: After surgery, complete the remaining chemotherapy cycles and move on to obinutuzumab monotherapy maintenance.

III. The Breakthrough: Treatment Course and Technical Points

Treatment Timeline

1. Induction phase.

Cycle 1: Pre-treatment chest CT showed bilateral pleural effusions with a little subsegmental atelectasis at both lung bases, without chest tightness or shortness of breath, so this was observed. Because the patient declined PICC placement and given the risk of tumour lysis syndrome (TLS) in the first cycle, she received the G-CVP regimen with cyclophosphamide given over two days.

Cycle 2: Her symptoms improved and pleural fluid volume was essentially unchanged. A PICC was placed and the standard G-CHOP regimen was given.

Cycle 3: After two cycles her abdominal distension, abdominal pain and poor appetite had clearly improved. One week before this treatment she developed a cough, and repeat chest CT showed a marked increase in pleural fluid (Figure 2A). Thoracentesis was performed; flow cytometry and pathology of the pleural fluid showed a non-tumour origin, while pleural fluid routine and biochemistry indicated chylothorax. After MDT discussion with thoracic surgery and other specialties, conservative treatment was chosen first. Daily drainage was 800 ml, symptoms improved after drainage, and G-CHOP continued as planned.

Cycles 4 and 5: G-CHOP chemotherapy continued; the chylothorax was repeatedly drained without resolving.

2. Surgical intervention phase.

Thoracoscopic thoracic duct ligation: On insertion of the thoracoscope, a large volume of chyle — about 1000 ml — was seen in the pleural cavity, and after aspiration a small amount of pleural adhesion was evident. After adhesiolysis, multiple chyle leakage points were seen on the diaphragmatic surface; the thoracic duct was dissected and clipped with a Hem-o-lok clip. Chyle leakage on the mediastinal surface was still visible after clipping. A size 28 silicone drainage tube was placed at the end of the procedure.

Lymphangiography: Lymphatic vessels were seen draining along the iliac vessels towards the abdomen; lipiodol reached the cisterna chyli and ascended to the lower thoracic duct (at the level of the diaphragm) but did not advance further, with no definite extravasation of lipiodol along its course (Figure 2C). Because no clear leak point was identified, lymphatic embolisation was not performed.

3. Maintenance phase.

Postoperative chest CT showed a small right-sided pleural effusion with mild pleural adhesion and thickening (Figure 2B), markedly improved from before, and some bilateral lymph nodes slightly smaller than before. The patient is currently on obinutuzumab monotherapy maintenance and has had no further pleural effusion.

Diagnosing Chylothorax and Excluding Malignant Effusion

The diagnosis of chylothorax in this case rested on solid evidence:

Nature of the fluid: a milky or chylous appearance, with pleural fluid routine and biochemistry consistent with chylothorax.

Exclusion of other causes: flow cytometry and pathology of the pleural fluid showed a non-tumour origin, excluding malignant pleural effusion from lymphomatous pleural infiltration.

Mechanistic inference: FL is one of the most common causes of non-traumatic chylothorax (about 70%)[7]; the mechanism may involve raised lymphatic hydrostatic pressure, high lymphatic permeability[8], and lymphatic endothelial injury after lymphoma treatment together with altered traction and external compression of lymphatic vessels by abdominal lymph nodes. In this case the chylothorax appeared after cycle 3 of chemotherapy began, and the disease course suggests multiple potential mechanisms. First, the patient presented with FL that was FLIPI-2 high risk with a high tumour burden, and confluent retroperitoneal lymph nodes persistently compressed the lymphatics, chronically raising lymphatic hydrostatic pressure and damaging the lymphatic endothelial barrier, increasing permeability. Second, chemotherapy drugs may induce inflammatory injury to the lymphatic endothelium, further aggravating chyle leakage; at the same time, regression of tumour lesions after anti-tumour treatment, local nodal traction and anatomical changes in lymphatic return pathways cannot be excluded as a source of occult leakage. Having excluded direct tumour infiltration of the pleura by pleural fluid cytology, the team leaned towards non-traumatic chylothorax mediated jointly by a high tumour burden and chemotherapy-related lymphatic endothelial injury.

Technical Considerations in Thoracoscopic Surgery

The key intraoperative finding was multiple chyle leakage points on the diaphragmatic surface, suggesting that the leak may not have been a single rupture of the thoracic duct trunk but rather multiple small lymphatic leaks or opened accessory lymphatic pathways. Lymphatic embolisation is chiefly applicable to localised, single leak lesions identifiable on imaging; here the disease consisted mainly of multiple tiny lymphatic leaks with abnormal multi-pathway lymphatic return and no target for embolisation, so embolisation alone could not have controlled all the leak points. On this basis the team chose thoracoscopic thoracic duct ligation, blocking the main return pathway of the thoracic duct to reduce fluid pressure throughout the lymphatic circulation and so decrease the volume leaking from multiple small sites. After ligation a small amount of leakage persisted on the diaphragmatic surface, further confirming the presence of accessory lymphatic pathways or anatomical variation of the thoracic duct — about 40% of individuals have variant thoracic duct anatomy[9], which explains why persistent chyle leakage can still occur after ligation. In this case the postoperative drainage gradually decreased to nothing, suggesting that once the main pathway was closed, flow through accessory pathways could be controlled by the body's own repair.

IV. Outcome Assessment and Follow-up Strategy

Short-Term Efficacy and Functional Status

As of now (during maintenance therapy after thoracic duct ligation), the patient's preoperative lumbar soreness, abdominal distension and difficulty passing stool have completely resolved; eating has returned to normal, with no chest tightness, shortness of breath or other discomfort. Imaging assessment: abdominopelvic and retroperitoneal lymph nodes continue to shrink, the spleen has reduced in size, and bone marrow metabolic activity is reduced; chest CT shows the right pleural effusion essentially absorbed, leaving only a small amount of pleural adhesion and thickening, with no sign of chylothorax recurrence. The tumour response was assessed as CR, and the chylothorax as clinically cured.

Subsequent Treatment and Follow-up Plan

Obinutuzumab monotherapy maintenance continues as planned (once every 8 weeks for a total of 2 years). Follow-up monitoring: chest ultrasound or CT every 3-6 months to monitor pleural effusion and assess lymphoma response; regular monitoring of blood counts, liver and kidney function and lactate dehydrogenase; and long-term attention to immune function and the risk of second tumours.

V. What This Case Teaches

1. Disentangling Cause and Effect Between Non-Traumatic Chylothorax and Lymphoma

This chylothorax arose during systemic treatment of lymphoma, so it was necessary to distinguish whether it was caused by direct tumour invasion or compression of lymphatic vessels, or whether it was a treatment-related complication. Pleural fluid pathology and flow cytometry excluded tumour infiltration, supporting tumour-related lymphatic dysfunction (external compression, high permeability) as the main mechanism. This underlines how important differential diagnosis is when a lymphoma patient develops pleural effusion.

2. The Core Value of MDT Collaboration in Managing Complex Complications

The success of this case lay in close collaboration between lymphoma medicine and thoracic surgery: the lymphoma team insisted on completing systemic chemotherapy under controlled conditions, laying the foundation for curing the lymphoma, while thoracic surgery intervened promptly after conservative treatment failed, ending the vicious circle of chylothorax with thoracoscopic surgery. The continuous involvement of the nutrition team (low-fat diet, protein supplementation, fat-soluble vitamin replacement) was also a key element in maintaining continuity of treatment.

3. Timing and Expected Efficacy of Thoracic Duct Ligation in Non-Traumatic Chylothorax

Conventionally, surgery is considered after conservative treatment of non-traumatic chylothorax fails, but its efficacy is inferior to that in traumatic chylothorax (response rate 27% vs 50%)[2]. The experience from this case suggests that for malignancy-associated chylothorax that fails to resolve with repeated drainage, one should not wait indefinitely for spontaneous healing. When daily drainage persistently exceeds 500 ml, drainage has continued for more than 2 weeks, and the anti-tumour treatment schedule is being disrupted, surgical intervention should be actively assessed[5-6]. Intraoperatively, attention must be paid to anatomical variation of the thoracic duct and the presence of accessory lymphatic pathways; postoperative lymphangiography can further assess leakage.

Expert Commentary

Prof. Zhang Wei

Chief Physician, Professor and Master's Supervisor, Department of Hematology, Peking Union Medical College Hospital

FL is the most common subtype among indolent B-cell lymphomas and predominantly involves lymph nodes. In advanced disease, patients without treatment indications may be managed by watchful waiting; this patient, however, had extensive whole-body lymph node, bone marrow, bowel and serosal involvement, with massive pleural effusion, severe abdominal distension and B symptoms, and therefore had a clear indication for treatment.

In treating FL, chylous pleural effusion is a clinical difficulty. Because the lymphatics are damaged, the lymphatic fistula is often hard to resolve even when the lymphoma goes into remission; the patient needs intermittent pleural drainage indefinitely, and repeated lymphatic fistula causes loss of nutrients, leading to malnutrition or secondary infection — so that even with radiological remission the patient cannot return to a normal life, and may even become disabled or die from complications. In institutions without an MDT team, after treating the lymphoma the patient must still travel to other hospitals specifically to have the lymphatic fistula managed; the absence of multidisciplinary discussion and assessment — clarifying the cause of the chylous effusion, localising the leak, and determining surgical timing, risk and prognosis — results in continual delays in diagnosing and treating the fistula.

Before treatment, through repeated multidisciplinary collaboration by the MDT team at Beijing Arion Cancer Hospital — with the full support of nutrition, thoracic surgery and radiology from the outset — this patient, presenting with advanced lymphoma of extremely high tumour burden, malnutrition and a severely depleted state, underwent immunochemotherapy smoothly and with a marked response. More importantly, the team pursued not only clinical and radiological remission but also, in order to truly restore the patient to normal life and reintegration into society, the later diagnosis and treatment of the lymphatic fistula — which reflects the MDT team's refined technique and spirit of collaboration, and achieved a genuine complete remission of advanced disease.

Lymphoma is a rather special type among solid tumours, often involving multiple organs and both nodal and extranodal sites, with a peak incidence in middle and older age, so patients frequently have other comorbidities; multidisciplinary collaboration with participation from multiple specialty groups is crucial to supporting lymphoma physicians during treatment. In recent years, more and more novel agents — such as bispecific antibodies and CAR-T cell therapy — will certainly bring better survival and quality of life to patients with FL.

References

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[3] Platis IE, Nwogu CE. Chylothorax. Thorac Surg Clin 2006;16:209-14.

[4] Cerfolio RJ, Allen MS, Deschamps C, et al. Postoperative chylothorax. J Thorac Cardiovasc Surg 1996;112:1361-5; discussion 1365-6.

[5] Dugue L, Sauvanet A, Farges O, et al. Output of chyle as an indicator of treatment for chylothorax complicating oesophagectomy. Br J Surg 1998;85:1147-9.

[6] Marts BC, Naunheim KS, Fiore AC, et al. Conservative versus surgical management of chylothorax. Am J Surg 1992;164:532-4; discussion 534-5.

[7] Teng CL, Li KW, Yu JT, et al. Malignancy-associated chylothorax: a 20-year study of 18 patients from a single institution. Eur J Cancer Care (Engl) 2012;21:599-605.

[8] O'Callaghan AM, Mead GM. Chylothorax in lymphoma: mechanisms and management. Ann Oncol 1995;6:603-7.

[9] Nair SK, Petko M, Hayward MP. Aetiology and management of chylothorax in adults. Eur J Cardiothorac Surg 2007;32:362-9.