An unusual case of chylothorax

Our plain-English summary of An unusual case of chylothorax, by L.A. Benninger, J.A. Ross, M.E. Leon, et al (Respiratory Medicine Case Reports, 2018).

The study

• Authors: L.A. Benninger, J.A. Ross, M.E. Leon, R. Reddy
• Journal: Respiratory Medicine Case Reports
• Published: 2018;25:318-322
• Type of article: Case report
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Pleural effusions occur in up to 70% of cases of malignant pleural mesothelioma (MPM). However, MPM rarely presents as a chylous effusion making it a diagnostic challenge. There are only six reported cases to date. Most cases of chylothoraces due to malignancy are due to lymphoma or bronchogenic carcinoma. We report an interesting case of MPM in a 75-year-old man who presented with recurrent chylothorax. He reported a four-month history of dyspnea and chest discomfort. Chest x-ray revealed a pleural effusion. Pleural fluid analysis was consistent with a chylothorax. Pleural fluid cytology was negative for malignancy. Computed tomography of the chest showed pleural calcifications, mediastinal adenopathy and left lung infiltrate. A fine needle aspirate of the lymph node and transbronchial biopsy specimen (TBBX) of the left lung infiltrate showed extensive reactive appearing mesothelial cells but none that appeared malignant. A video assisted thoracoscopic surgery was suggested but the patient declined. He returned 3 months later with recurrent pleural effusion and worsening airspace disease. Thoracentesis revealed a chylothorax again. Repeat analysis of TBBX and lymph node specimens showed extensive reactive appearing mesothelial cells. Due to concern for MPM, ancillary testing was obtained - loss of BRCA1 associated protein (BAP-1) and CDKN2A/p16 gene deletion. BAP1 staining was lost in the mesothelial cells supporting MPM. This case highlights a rare cause of MPM presenting as a chylous effusion. In a patient with an unknown etiology of chylothorax, MPM must remain in the differential.

In plain English

This case report described a 75-year-old man diagnosed with malignant pleural mesothelioma, epithelioid subtype, after repeated chylous pleural effusions (milky, fat-rich fluid around the lung). He had worked as a lawyer all his life, with no occupational exposures and no tobacco use. It did not describe any asbestos exposure. Fluid from his left chest had a triglyceride level of 1406 mg/dL, and cytology was negative for malignancy. CT showed pleural calcifications, enlarged chest lymph nodes and a left lung infiltrate. Early biopsies showed mostly bland-looking mesothelial cells and could not settle the diagnosis. Three months later he had a new right-sided chylothorax. Lymph node cells showed loss of BAP-1 staining, supporting mesothelioma, but FISH found no homozygous CDKN2A/p16 deletion; a third lung biopsy confirmed the diagnosis. He was offered no treatment because of poor functional status but received an indwelling pleural catheter for palliation, and died in hospital four months after diagnosis. Autopsy found tumor in the pleura, lung lymphatics and chest lymph nodes. The authors concluded that mesothelioma must remain a possible cause of chylothorax, though rare.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (single patient)
• Who was studied: One 75-year-old Caucasian man with heart disease, reported by physicians and pathologists at the University of Florida College of Medicine. No date of care is given.
• Exposure: No asbestos exposure is described for this patient. The article states he worked as a lawyer all his life, had no occupational exposures, and had no history of tobacco use.
• Main results:
  • Left pleural fluid had a total triglyceride level of 1406 mg/dL, consistent with a chylous effusion.
  • Pleural fluid cytology was negative for malignancy.
  • Chest CT showed left lung airspace disease, pleural calcifications and mediastinal adenopathy.
  • A lymphangiogram suggested an obstructive process in the lymph nodes.
  • Three months later, thoracentesis of a new right-sided effusion showed chylothorax.
  • In the lymph node specimen, BAP-1 staining was lost in mesothelial cells, supporting mesothelioma. The CDKN2A/p16 FISH test did not show a homozygous deletion.
  • A third transbronchial biopsy of the left lung infiltrate confirmed malignant pleural mesothelioma, epithelioid subtype.
  • Because of the patient's poor functional status, no treatment was offered. An indwelling pleural catheter was placed for palliation.
  • The patient died during a hospital admission four months after diagnosis.
  • At autopsy, the pleura was thickened up to 1 cm on both sides, mostly the left. Tumor cells were mainly within lung lymphatics, with metastatic cells in multiple mediastinal lymph nodes.
• The authors' conclusion: The authors concluded that malignant pleural mesothelioma must remain in the differential diagnosis of chylothorax, although it is a rare cause.

Topics

Medical terms in this study, explained in our Lexicon: Pleural Effusion, Pleural Mesothelioma, Bronchogenic Carcinoma, Dyspnea, Chest X-Ray, Fluid Cytology, Pleural Calcification, Aspirate.

Related studies

• Chest pain and recurrent chylothorax: an unusual presentation of malignant pleural mesothelioma — D.R. Darley, E. Granger, et al. (2017)
• Medical thoracoscopic talc pleurodesis for chylothorax due to lymphoma: a case series — D.C. Mares, P.N. Mathur (1998)
• Treatment of postoperative chylothorax through laparoscopic thoracic duct ligation — B.C. Vassallo, D. Cavadas, et al. (2002)
• Laparoscopic thoracic duct clipping for persistent chylothorax after extrapleural pneumonectomy — N. Tsubokawa, Y. Hamai, et al. (2012)
• A Cause of Bilateral Chylothorax: A Case of Mesothelioma without Pleural Involvement during Initial Diagnosis — E. Kurtipek, M.İ. Eren Karanis, et al. (2015)
• Robotic Treatment of Postoperative Chylothorax — A. Fiorelli, A.C. Izzo, et al. (2025)

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