Diffuse malignant mesothelioma arising in a paracolostomy hernial sac

Our plain-English summary of Diffuse malignant mesothelioma arising in a paracolostomy hernial sac, by P.B. Bethwaite, R. Evans, D.K. Naik, et al (Histopathology, 1996).

The study

• Authors: P.B. Bethwaite, R. Evans, D.K. Naik, B. Delahunt, C.A. Teague
• Journal: Histopathology
• Published: 1996;29(3):282-4
• Type of article: Case report
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

The authors reported what they described as the first documented case of malignant mesothelioma arising in a longstanding paracolostomy hernia sac, from Wellington, New Zealand. An 87-year-old Caucasian man presented with a 3-month history suggestive of small bowel obstruction. Ten years earlier he had undergone abdominoperineal resection for a Dukes C rectal adenocarcinoma, with a left iliac fossa end-colostomy. He had no occupational or recreational history of asbestos exposure. At laparotomy, a firm white tumour infiltrated the hernial sac, stoma and abdominal wall, and there was a moderate peritoneal effusion. There was no local recurrence of the rectal cancer. After small bowel resection, colostomy resiting and hernia repair, he collapsed and died on the seventh post-operative day. No autopsy was performed. The specimen showed a 38 mm x 35 mm mass around the stoma, continuous with a 65 mm x 40 mm hernial sac, and mesenteric nodules up to 20 mm. Microscopy showed invasive tubulo-papillary mesothelioma. The tumour cells were CEA-negative, cytokeratin-positive and strongly EMA-positive, which distinguished the tumour from recurrent colonic adenocarcinoma. Ascitic fluid cytology also showed malignant mesothelioma. The sac wall contained foci of mesothelial hyperplasia. Mean AgNOR counts and PCNA indices were 4.40 and 10.2% in the hyperplastic mesothelium, and 5.59 and 36.7% in the invasive tumour. The authors concluded that these values supported both a reactive and a malignant component. They stated that the case supports the idea that occasional peritoneal mesotheliomas may arise after long-standing chronic irritation and mesothelial hyperplasia.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This case report described one patient, an 87-year-old Caucasian man with symptoms suggestive of small bowel obstruction. Ten years earlier, surgery for rectal cancer had left him with a colostomy, and he now had a large hernia beside it. The report stated that he had no occupational or recreational history of asbestos exposure. At surgery, a firm white tumour was infiltrating the hernial sac, stoma and abdominal wall. Microscopy and staining identified an invasive tubulo-papillary mesothelioma, distinguishing it from a recurrence of his bowel cancer. Abdominal fluid also showed malignant mesothelioma. The sac wall also contained areas of mesothelial hyperplasia (overgrowth of lining cells). Two cell-growth measures, AgNOR counts and PCNA indices, were 4.40 and 10.2% in the hyperplastic areas and 5.59 and 36.7% in the tumour. The authors said these counts supported a diagnosis of malignancy. He died seven days after surgery, and no autopsy was done. The authors called this the first documented case arising in a paracolostomy hernia sac. They concluded that it supports the idea that occasional peritoneal mesotheliomas may arise after long-standing chronic irritation and mesothelial hyperplasia.

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 87-year-old Caucasian man treated by authors based in Wellington, New Zealand. Ten years earlier he had an abdomino-perineal resection for rectal adenocarcinoma, with a left iliac fossa end-colostomy.
• Exposure: No occupational or recreational history of asbestos exposure was reported. The tumour arose in a longstanding paracolostomy (parastomal) hernia sac.
• Main results:
  • At laparotomy, a firm white tumour mass was infiltrating the hernial sac, stoma and abdominal wall.
  • Microscopy of the tumour mass and mesenteric nodules showed an invasive tubulo-papillary mesothelioma.
  • Immunohistochemical staining (negative for CEA, positive for cytokeratin, strong membranous EMA staining) distinguished the tumour from recurrent colonic adenocarcinoma.
  • Cytological examination of the ascitic fluid also showed changes of malignant mesothelioma.
  • The hernial sac wall showed foci of mesothelial hyperplasia in addition to invasive tumour.
  • In the hyperplastic mesothelium, the mean AgNOR count was 4.40 and the PCNA index was 10.2%.
  • In the invasive tumour, the mean AgNOR count was 5.59 and the PCNA index was 36.7%.
  • The authors stated that these counts supported the diagnosis of malignancy. They cited their previous finding that mean AgNOR counts over 4.4 and PCNA indices over 20% help distinguish reactive from malignant mesothelial processes.
  • The patient collapsed and died on the seventh post-operative day. Permission for autopsy could not be obtained.
• The authors' conclusion: The authors concluded that the case lends support to the idea that occasional cases of peritoneal mesothelioma may arise following long-standing chronic irritation and mesothelial hyperplasia.

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Adenocarcinoma, Asbestos Exposure, Laparotomy, Bowel Resection, Autopsy, Tubulopapillary, Mesothelioma.

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