Mesothelial tumors
Benign multicystic mesothelioma

Topic Completed: 1 August 2013

Revised: 1 March 2019

Copyright: 2003-2019,, Inc.

PubMed Search: Benign multicystic mesothelioma pleural
Page views in 2018: 1,389
Page views in 2019 to date: 438
Cite this page: Avadhani V. Benign multicystic mesothelioma. website. Accessed March 23rd, 2019.
Definition / general
  • Now termed multicystic mesothelial tumor of borderline biologic potential (MMTBBP)
  • Very rare in pleura - most cases reported have been from peritoneum
  • Usually reported in women of reproductive age (mean age 37 years)
  • Peritoneum, pleura, pericardium
Clinical features
  • Pleura: localized mass found on imaging studies
  • Abdomen: chronic or intermittent abdominal pain (most common), abdominal distension, urinary hesitancy
Radiology description
Radiology images

Images hosted on other servers:

Peritoneal tumors:

Sagittal endovaginal sonogram (Figure 17b)

IV contrast enhanced CT scans (Figures 18a & b)

Case reports
  • Surgical resection
  • Also sclerosants, hormonal therapy, radiotherapy, chemotherapy
  • Peritoneal lesions may recur
  • Usually patients with recurrent disease have long survival as lesion grows slowly
Gross description
  • Well circumscribed mass of multiple thin walled cysts with serous fluid, easily dissected from surrounding tissue
Gross images

Images hosted on other servers:

Peritoneal masses:

Multicystic mass

Multiple thin walled, irregular shaped cysts

Microscopic (histologic) description
  • Cystic spaces lined by single layer of bland cuboidal mesothelial cells, some with hobnailing
  • Cysts are filled with eosinophilic serous fluid
  • Stroma is hypocellular and collagenized
  • No nucleoli or mitotic activity
Microscopic (histologic) images

Images hosted on other servers:

Peritoneal tumors:

Multiple thin walled, irregular cysts (Left: Figure 16a)

Loose fibrous stroma between cysts
(Figure 16b)

Mesothelial cells line cysts

Cytology description
  • Fluid cytology and cell blocks show benign appearing mesothelial cells in flat sheets and small clusters, with low N/C ratio, rounded nuclei and indistinct nucleoli (Diagn Cytopathol 2010;38:192)
Positive stains
Negative stains
Electron microscopy description
Differential diagnosis
Back to top