Cellular cannibalism and consequent thrombocytopenia in a patient with bone marrow metastasis of malignant pleural mesothelioma: A case report

Our plain-English summary of Cellular cannibalism and consequent thrombocytopenia in a patient with bone marrow metastasis of malignant pleural mesothelioma: A case report, by M. Nishikubo, Y. Kin, S. Tane, et al (Molecular and Clinical Oncology, 2021).

The study

• Authors: M. Nishikubo, Y. Kin, S. Tane, K. Nakamura, Y. Miyagi, A. Miura, W. Nishio, H. Senzaki, K. Uchino
• Journal: Molecular and Clinical Oncology
• Published: 2021;15(2):163
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Cellular cannibalism is a tumor activity where a cell is engulfed by another cell. This process promotes tumor cell survival under unfavorable conditions. The current report describes an extremely rare case of thrombocytopenia resulting from cellular cannibalism in a patient with bone marrow metastasis due to malignant pleural mesothelioma (MPM). A 77-year-old male presented with hemothorax and thrombocytopenia. He was diagnosed with MPM of the sarcomatoid cell type. However, his disease progressed rapidly and he died 11 days after admission. Bone marrow aspiration revealed metastatic MPM cells that had engulfed other blood cells. Accordingly, the observed thrombocytopenia was attributed to cellular cannibalism by metastatic MPM tumor cells. To the best of our knowledge, this is the first reported case of thrombocytopenia due to cellular cannibalism in a patient with this type of malignancy (MPM). The results suggested that although MPM rarely metastasizes to the bone marrow, bone marrow aspiration could be useful in such cases.

Copyright: © Nishikubo et al.

In plain English

This case report from Osaka Saiseikai Nakatsu Hospital in Japan described one patient. He was a 77-year-old male smoker who had worked as a machine tool manufacturer and had a history of occupational asbestos exposure; the fiber type was not stated. He was referred with blood in the chest cavity (hemothorax). Blood tests showed anemia and a low platelet count of 1.9 x 10^4 per cubic millimetre. A pleural biopsy showed malignant pleural mesothelioma of the sarcomatoid cell type. His platelet count stayed between 1.0 and 3.0 x 10^4 despite daily platelet transfusions. Bone marrow aspiration found clustered atypical cells at a frequency of 2.2%. Some had engulfed other blood cells, which the authors read as cellular cannibalism, and the cells stained positive for AE1/AE3. With no sign of disseminated intravascular coagulation, the authors attributed the low platelets to cellular cannibalism by bone marrow metastasis of mesothelioma (stage IV). He died 11 days after admission. The authors noted the marrow sample was too small to test other mesothelioma markers, and that apoptosis markers could not be tested.

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 77-year-old male smoker referred with hemothorax to Osaka Saiseikai Nakatsu Hospital, Japan; dates not given
• Exposure: Occupational asbestos exposure in a former machine tool manufacturer; fiber type, duration and dose not reported
• Main results:
  • On presentation the patient had anemia and thrombocytopenia: hemoglobin 6.6 g/dl, white blood cell count 19.2 x 10^3/mm3, platelet count 1.9 x 10^4/mm3
  • The pleural biopsy contained spindle tumor cells positive for calretinin, D2-40, WT-1 and AE1/AE3, consistent with sarcomatoid malignant pleural mesothelioma
  • The platelet count did not rise (1.0 to 3.0 x 10^4/mm3) despite daily transfusions of 10 to 20 units of platelet concentrate
  • Bone marrow aspirate smears showed large, cohesive, clustered atypical cells at a frequency of 2.2%
  • Some atypical marrow cells had engulfed other blood cells, which the authors interpreted as cellular cannibalism
  • The marrow atypical cells stained positive for AE1/AE3
  • The authors found no evidence of disseminated intravascular coagulation or other thrombocytopenic disorders
  • The patient's disease progressed rapidly and he died 11 days after admission
• The authors' conclusion: The authors made a final diagnosis of bone marrow metastasis of malignant pleural mesothelioma (stage IV) with thrombocytopenia due to cellular cannibalism. They stated that, to their knowledge, this was the first reported such case involving bone marrow metastasis from this tumor, and suggested that clarifying the mechanism may identify a treatment target.
• Limitations the authors state:
  • Other mesothelioma-specific markers (calretinin, D2-40, WT-1) could not be confirmed in the bone marrow because the specimen volume was insufficient
  • Staining for apoptosis markers could not be performed; cellular cannibalism was inferred from cell appearance under the microscope

Topics

Medical terms in this study, explained in our Lexicon: Metastasis, Pleural Mesothelioma, Hemothorax, Sarcomatoid.

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• Decreased asbestos-induced lung inflammation and fibrosis after radiation and bone marrow transplant — J. Levis, R. Loi, et al. (2008)
• Bone marrow alterations induced in mice with inhalation of chrysotile asbestos — G.A. Boorman, J.H. Dean, et al. (1984)
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• Induction of chromosomal aberrations in bone marrow cells of asbestotic rats — N. Fatma, S.G. Khan, et al. (1992)

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