Hyperplastic mesothelial cells in lymph nodes: report of six cases of a benign process that can stimulate metastatic involvement by mesothelioma or carcinoma

Our plain-English summary of Hyperplastic mesothelial cells in lymph nodes: report of six cases of a benign process that can stimulate metastatic involvement by mesothelioma or carcinoma, by P. Argani, J. Rosai (Human Pathology, 1998).

The study

• Authors: P. Argani, J. Rosai
• Journal: Human Pathology
• Published: 1998;29(4):339-46
• Cited by: 42 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We report six cases of hyperplastic mesothelial cells located in the sinuses of lymph nodes. All patients but one had a concurrent serosal fluid collection (two pericardial, two pleural, one abdominal) at the time of the lymph node biopsy. All effusions cleared with treatment of the underlying disorder, which included lymphoproliferative processes, congestive heart failure, and inflammatory diseases (Dressler syndrome, vasculitis, and glomerulonephritis). Four cases were associated with vascular prominence of the involved nodal sinuses, a feature that may reflect the cause of the underlying effusion or support the transient persistence of benign mesothelial cells in lymph nodes. Two cases were characterized by distention of the nodal sinuses by sheets of mitotically active mesothelial cells. The differential diagnosis includes metastatic carcinoma, keratin-positive dendritic cells native to lymph nodes, and metastatic malignant mesothelioma. Because the latter shares both clinical and morphological features with cases of benign mesothelial cells in lymph nodes, we believe that this distinction may not always be possible in a given biopsy specimen and therefore that careful clinical follow-up is required in such cases.

In plain English

This article was a case series from the pathology department at Memorial Sloan-Kettering Cancer Center. It described six patients, taken from one author's consultation files, whose lymph nodes contained clusters of hyperplastic mesothelial cells. These are the cells that line the body cavities. The patients were aged 14 to 61. Five of the six had a fluid collection in a body cavity. Their underlying conditions included Hodgkin's disease, chronic lymphocytic leukemia, congestive heart failure, and inflammatory diseases. The mesothelial cells sat in the lymph node sinuses. In two cases they formed sheets with dividing cells, averaging 2 mitoses per 10 high-power fields. Stains supported the cells being mesothelial, and they were negative for adenocarcinoma markers. All effusions resolved with treatment of the underlying disorder. Follow-up of 4 months to 2 years showed no evidence of disease. The authors concluded the cases were benign. They added that telling this apart from lymph node spread of malignant mesothelioma may not always be possible in a single biopsy, so careful clinical follow-up is required. The article did not discuss asbestos exposure.

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 series (six case reports)
• Who was studied: Six patients (two women, four men, aged 14 to 61 years) whose cases came from the consultation files of one author (J.R.) at the Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York; dates of the cases are not given
• Exposure: The article does not study or discuss asbestos or any fiber exposure. One patient's diagnoses included pneumoconiosis, with no type stated.
• Main results:
  • Five of the six patients had radiographically documented fluid collections within a serosal cavity.
  • In all cases, clusters of mesothelial cells were confined to the lymph node sinuses.
  • In cases 3 and 6, sheets of mesothelial cells expanded the nodal sinuses, and mitoses averaged 2 per 10 high-power fields in each case.
  • The four cases other than cases 3 and 6 showed varying degrees of vascular prominence of the nodal sinuses.
  • Keratin stains supported the mesothelial nature of the cells, and adenocarcinoma markers were negative in all cases tested.
  • Only the lymph node of case 4 contained both a malignant process (chronic lymphocytic leukemia, minimal involvement) and mesothelial cells.
  • All patients' effusions resolved with treatment of the underlying disorder. Follow-up ranged from 4 months to 2 years, with no evidence of disease reported in any patient.
• The authors' conclusion: The authors concluded that the cases were benign processes. They based this on the absence of overtly malignant features and on clinical follow-up. They stated that distinguishing these cases from metastatic malignant mesothelioma may not always be possible in a given biopsy, so careful clinical follow-up is required.
• Limitations the authors state:
  • The authors stated that a definitive distinction from metastatic malignant mesothelioma may not always be possible.
  • Only minimal gross description of the involved lymph nodes was available.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelial Cells, Mesothelioma, Carcinoma, Pericardial, Biopsy, Differential Diagnosis, Malignant Mesothelioma.

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