Pleura & peritoneum
Pleura mesothelial tumors
Mesothelioma (pleura)-desmoplastic
Author: Vaidehi Avadhani, M.D.
Last author update: 1 November 2013
Last staff update: 17 July 2024
Copyright: 2003-2024, PathologyOutlines.com, Inc.
PubMed Search: Desmoplastic mesothelioma
See Also: Mesothelioma
Table of Contents
Definition / general | Case reports | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Differential diagnosisCite this page: Avadhani V. Mesothelioma (pleura)-desmoplastic. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pleuramesotheliomadesmoplastic.html. Accessed December 21st, 2024.
Definition / general
- > 50% of tumor shows desmoplastic pattern
- 5 - 10% of malignant mesotheliomas
- Note: DMM may refer to desmoplastic or diffuse malignant mesothelioma
Case reports
- 2 cases with rapid decline (Med Electron Microsc 2003;36:173)
Microscopic (histologic) description
- Characteristic dense collagenized tissue separated by atypical cells arranged in a storiform or haphazard pattern (J Clin Pathol 1992;45:295), comprising > 50% of tumor
- Presence of sarcomatoid areas, bland collagen, necrosis, stromal / fat invasion help differentiate from organizing pleuritis (Am J Surg Pathol 2011;35:1823)
- Paucicellularity of lesion may lead to misdiagnosis
Microscopic (histologic) images
Images hosted on other servers:
Storiform pattern
Positive stains
- Keratin stains:
- Pancytokeratin is positive in > 70% of sarcomatoid mesotheliomas (including desmoplastic)
- Use multiple cytokeratin antibodies (AE1 / AE3, CAM 5.2 and CK7)
- If only focal cytokeratin staining, additional blocks should be stained along with vimentin to check for tissue antigen integrity
- D2-40, calretinin
- GLUT1: 53% sensitivity, 98% specific
Negative stains
- CD31 (positive in angiosarcoma), CD34 (positive in solitary fibrous tumor, Hum Pathol 1995;26:428)
- S100 (positive in neurogenic tumors, mesotheliomas may show focal staining)
- CD45
- Some muscle markers are focally positive
Electron microscopy description
- Sarcomatous mesotheliomas including desmoplastic type have no specific ultrastructural features
Differential diagnosis
- Calcifying fibrous pseudotumor of pleura / localized fibrous tumor:
- Whorls and haphazard arrays of keloidal collagen
- Also psammomatous and dystrophic calcification
- Fibrous pleurisy / pleuritis:
- Cytokeratin highlights malignant cells of mesothelioma; if present in fat, skeletal muscle or connective tissue, is an important clue to desmoplastic mesothelioma
- "Fake fat" may be seen in organizing pleuritis due to artefactual changes in dense fibrous connective tissue
- S100, laminin and collagen are negative in fake fat (Arch Pathol Lab Med 2013;137:647)
- Solitary fibrous tumor: CD34+
