Peritoneal washing cytology findings of disseminated myxoid leiomyosarcoma of uterus: report of a case with emphasis on possible differential diagnosis

Our plain-English summary of Peritoneal washing cytology findings of disseminated myxoid leiomyosarcoma of uterus: report of a case with emphasis on possible differential diagnosis, by W.K. Ng, P.C. Lui, L. Ma (Diagnostic Cytopathology, 2002).

The study

• Authors: W.K. Ng, P.C. Lui, L. Ma
• Journal: Diagnostic Cytopathology
• Published: 2002;27(1):47-52
• Type of article: Case report
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We report the cytology findings of a rare case of myxoid leiomyosarcoma of the uterus with intraabdominal dissemination. The cytology showed uniformly dispersed spindly to polygonal "epithelioid" tumor cells focally linked by background matrix. Spindly tumor cells attaching to and radiating from branching capillary structures were also present. Occasionally, scattered "signet-ring" cells were found, mimicking metastatic poorly differentiated adenocarcinoma. The background mucoid substance was more conspicuous in the cell block sections. Gross and histologic examination of the surgical specimen revealed a large uterine leiomyosarcoma with prominent myxoid change. Ultrastructural study showed that the "signet-ring" appearance was mainly due to degenerative cytoplasmic change with ballooning of mitochondria, dilatation of endoplasmic reticulum, and elevation of outer nuclear membrane. In contrast to other spindle cell malignancies such as sarcomatoid mesothelioma, sarcomatoid carcinoma, or malignant melanoma, true sarcoma cells in general carry a distinctive cytologic appearance in washing/effusion fluid. In a correct clinical setting, the peculiar association with mucoid matrix and absence of classic lipoblasts should also raise the suspicion of metastatic myxoid leiomyosarcoma.

Copyright 2002 Wiley-Liss, Inc.

In plain English

This article was a case report from pathology departments in Hong Kong about one patient, a 74-year-old Chinese woman. She had several months of abdominal swelling and a 20 cm tumor attached to the left side of the uterus. Surgery found tumor deposits on the lining of the abdomen. Examination of the removed tumor showed a myxoid leiomyosarcoma, a malignant tumor with smooth muscle features and abundant mucoid material. The authors described how the tumor cells looked in fluid washed from the abdomen during surgery. They saw scattered spindle-shaped to polygonal cells in a mucoid background, and occasional "signet-ring" cells that could not be told apart from poorly differentiated adenocarcinoma. Electron microscopy indicated that the signet-ring look came from cell degeneration rather than mucin production. The tumor cells did not stain for cytokeratins, which the authors used to exclude sarcomatoid mesothelioma and sarcomatoid carcinoma. The authors concluded that malignant spindle cells with mucoid matrix, degenerative signet-ring cells and a pelvic mass in washing fluid from women should raise suspicion of myxoid leiomyosarcoma. The article did not address 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 report (single patient), with cytology, histology, immunohistochemistry and electron microscopy
• Who was studied: One 74-year-old Chinese woman with abdominal distension, seen at hospitals in Hong Kong
• Main results:
  • Surgery showed a malignant uterine tumor with deposits on the peritoneum and a small collection of mucoid substances in the pelvis. Histology showed a myxoid leiomyosarcoma.
  • The peritoneal washing smears showed uniformly dispersed spindly to polygonal tumor cells, focally linked by background matrix.
  • Occasional tumor cells had eccentric nuclei and abundant foamy cytoplasm, giving a signet-ring appearance.
  • The background mucin in the cell block stained with Alcian blue at pH 2.5 but not with mucicarmine.
  • In the tumor cells, the mesothelial markers (HBME-1 and calretinin) and the hormonal receptors were negative.
  • In the surgical tumor, the mitotic count was at most 8 per 10 high-power fields.
  • Electron microscopy found myofilaments with dense bodies, confirming smooth muscle differentiation. It indicated that the myxoid change was degenerative rather than secretory.
  • The authors stated that negative cytokeratin staining excluded sarcomatoid mesothelioma and sarcomatoid carcinoma in this case.
• The authors' conclusion: The authors concluded that malignant spindly cells with myxoid matrix, degenerative signet-ring cells and a pelvic mass in peritoneal washing or effusion fluid from female patients should at least raise suspicion of myxoid leiomyosarcoma.
• Limitations the authors state:
  • The authors stated that on appearance alone, the case may be indistinguishable from myxofibrosarcoma, malignant peripheral nerve sheath tumor or gastrointestinal stromal tumor.
  • The authors noted that immunohistochemistry has limitations for classifying sarcomas, especially with the small amount of material in cell blocks.

Topics

Medical terms in this study, explained in our Lexicon: Cytology, Differential Diagnosis, Epithelioid, Adenocarcinoma, Cell Block, Spindle Cell, Sarcomatoid, Mesothelioma.

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