Solitary (localized) pleural mesothelioma. A light- and electron-microscopic study

Our plain-English summary of Solitary (localized) pleural mesothelioma. A light- and electron-microscopic study, by T. Kawai, K. Yakumaru, A. Mikata, et al (The American Journal of Surgical Pathology, 1978).

The study

• Authors: T. Kawai, K. Yakumaru, A. Mikata, K. Kageyama, C. Torikata, Y. Shimosato
• Journal: The American Journal of Surgical Pathology
• Published: 1978;2(4):365-75
• Cited by: 49 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Six solitary (localized) pleural mesotheliomas were studied by light and electron microscopy. All the lesions were benign and were composed mainly of fibrous tissue of variable cellularity with or without cystic spaces lined by round cells. The lining cells of the cysts and the adjoining round plump cells were interpreted as true neoplastic cells of the fibroblast type. Results of light- and electron-microscopic study of human mesothelial cells and fetal mesothelial cells of rats were compared. The cytoplasmic organelles of the tumor cells were generally scanty, though rough endoplasmic reticulum, sparse mitochondria, intracellular bundles of fibrils, and numerous polysomes were seen. Some tumor cells had junctional apparatus and basement membrane and showed interdigitation of the plasma membrane. These cells lined the cystic spaces irregularly and also proliferated into the surrounding fibrous tissue, where they assumed a spindle shape and resembled fibroblasts. Ultrastructurally, the tumor cells were similar to mesothelial and stromal cells of fetal rat pleura. We speculated that the solitary (localized) mesotheliomas were probably derived from coelomic epithelium and that tumor cells remained undifferentiated or revealed minimal differentiation toward mesothelial cells.

In plain English

This study looked at six solitary (localized) pleural mesotheliomas. These tumors were surgically removed from four men and two women aged 36 to 45, and the cases came from four institutions in Japan. The authors examined all six tumors under the light microscope and three under the electron microscope, to work out which cell type the tumor arises from. All six tumors were benign. Three consisted entirely of fibrous tissue, and three were mixed fibrous and plump-cell tumors. They measured 3 to 10 cm. The authors considered plump cells lining cystic spaces to be the true tumor cells. They saw no transition between the mesothelial cells covering the tumor surface and the tumor cells. They found the tumor cells similar to mesothelial cells of fetal rats. Five patients had no history of asbestos exposure, and for the sixth this information was not obtainable. Five patients were well with no recurrence after surgery. The authors speculated that the tumor cells probably derive from coelomic epithelium, a layer of embryonic tissue. They noted that observing tumors at an early stage of development is necessary for studies of the cell of origin.

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: pathology study of six surgically removed tumors using light microscopy and electron microscopy, with comparison to human pleura and fetal rat pleura
• Who was studied: Six patients with solitary (localized) pleural mesothelioma: four men and two women aged 36 to 45, from four institutions in Japan (a university hospital, the National Cancer Center and two general hospitals). Electron microscopy was done on tissue from three tumors. Fetal rat pleura at the 16th day of gestation was also examined.
• Exposure: No exposure was studied. The authors report that five patients had no history of previous asbestos exposure, and that asbestos information was not obtainable for one patient.
• Main results:
  • All six tumors were benign.
  • Three tumors (cases 2, 4 and 6) consisted entirely of fibrous tissue. The other three were mixed fibrous and plump cellular tumors.
  • The tumors ranged from 3 to 10 cm in greatest dimension.
  • Mitoses (dividing cells) were seen in some tumors, but rarely.
  • The authors considered the plump cells, which lined cystic spaces and spread into the surrounding fibrous tissue, to be the true tumor cells.
  • No transition was seen between the mesothelial cells lining the pleura and the tumor cells.
  • The tumor cells were similar to fetal rat mesothelial cells.
  • After tumor removal, five patients were well with no evidence of recurrence.
  • Asbestos exposure and follow-up information was not obtainable for one patient.
• The authors' conclusion: The authors speculated that the tumor cells of solitary mesothelioma are probably derived from coelomic epithelium. They suggested that in most instances these cells remain as plump cells rather than becoming mature mesothelium.
• Limitations the authors state:
  • Two tumors (cases 4 and 6) appeared to have existed for a longer time. The authors stated that observing tumors at an early stage of development is necessary for studies of their cell of origin.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Fibroblast, Mesothelial Cells, Fibril, Polysome, Pleura, Mesothelioma, Epithelium.

Related studies

• Experimental lung tumors following specific intrabronchial application of chrysotile asbestos. Longitudinal light and electron microscopic investigations in rats — E. Fasske (1988)
• Solitary fibrous tumor of the pleura. An immunohistochemical, electron microscopic and tissue culture study of a tumor producing insulin-like growth factor I in a patient with hypoglycemia — E.H. Strøm, F. Skjørten, et al. (1991)
• Localized fibrous tumor of the serosal cavities. Immunohistochemical, electron-microscopic, and flow-cytometric DNA study — A.K. el-Naggar, J.Y. Ro, et al. (1989)
• The interactions between asbestos fibers and metaphase chromosomes of rat pleural mesothelial cells in culture. A scanning and transmission electron microscopic study — N.S. Wang, M.C. Jaurand, et al. (1987)
• Reactive and neoplastic serosal tissue. A light-microscopic, ultrastructural, and immunocytochemical study — J.W. Bolen, S.P. Hammar, et al. (1986)
• Peripheral biphasic adenocarcinoma of the lung: light microscopic and immunohistochemical findings — P.T. Cagle, L.C. Alpert, et al. (1992)

Browse more research in The American Journal of Surgical Pathology, or return to medical research.