Pleura & peritoneum
Pleura other tumors
Fibromatosis
Author: Vaidehi Avadhani, M.D.
Topic Completed: 1 March 2014
Minor changes: 29 October 2020
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: Fibromatosis pleura full text[sb]
See also: Soft tissue chapter
Table of Contents
Definition / general | Terminology | Epidemiology | Sites | Etiology | Clinical features | Radiology description | Radiology images | Case reports | Treatment | Clinical images | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology images | Positive stains | Negative stains | Differential diagnosis | Additional referencesCite this page: Avadhani V. Fibromatosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pleurafibromatosis.html. Accessed May 16th, 2021.
Definition / general
- Borderline neoplasm of deep soft tissue
Terminology
- Also called "desmoid tumor," aggressive fibromatoses
Epidemiology
- Any age
- Increased incidence in familial adenomatous polyposis (FAP)
Sites
- Deep soft tissue, abdomen, pelvis, peritoneum
Etiology
- In FAP (2% of all desmoids), tumors are due to germline mutations
- In sporadic desmoids, somatic mutations in β catenin or APC occur, leading to stabilization of the β catenin protein
Clinical features
- Intrathoracic fibromatoses does not cause symptoms until mass is large enough to compress pulmonary parenchyma or locally invade surrounding structures
Radiology description
- Well circumscribed on imaging with homogenous radiodensity
Radiology images
Images hosted on other servers:
Typical localization of desmoid tumors
Desmoid tumor of right musculus deltoideus
Desmoid of thoracic / abdominal wall
Desmoid tumor (arrows)
Heterogeneous uptake (arrows)
Case reports
- 17 year old girl with chest wall and intrathoracic desmoid tumors (Eur J Med Res 2009;14:240)
- 36 year old woman with sporadic colonic desmoid tumor with β catenin mutation (J Med Case Rep 2013;7:100)
- 62 year old woman with desmoid type fibromatosis arising after thoracotomy for lung cancer (Ann Thorac Cardiovasc Surg 2014;20:465)
Treatment
- Complete surgical excision with wide surgical margin is curative
- Local recurrences can occur with positive margins (Ann Thorac Surg 2004;78:1219)
Clinical images
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Desmoid tumor originates from transverse mesocolon
Gross description
- Fleshy, uniform tan cut surface with fibrous bands
- May deceptively appear to have a well circumscribed interface with surrounding tissue but microscopically the tumor infiltrates surrounding tissue
Gross images
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Colonic tumor
Microscopic (histologic) description
- Bland spindle cells arranged in sweeping bundles in a highly collagenized background, with scattered thick walled small blood vessels with open lumina and a small number of chronic inflammatory cells
Microscopic (histologic) images
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H&E
H&E (colon)
H&E (thigh)
Cytology images
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FNA smears
Positive stains
- β catenin:
- Both nuclear and cytoplasmic immunoreactivity is seen
- This protein is dysregulated in desmoid tumors and accumulates in nucleus
- Smooth muscle actin and muscle specific actin: variable staining
Negative stains
- CD34 and CD99 (positive in solitary fibrous tumor)
- ALK1 (positive in 36% of inflammatory myofibroblastic tumors in one series, Arch Pathol Lab Med 2006;130:1503)
Differential diagnosis
- Fibrinous and fibrous pleuritis:
- Acute reaction, showing thick areas of fibrin deposition along surface of pleura, which over time, develops to fibrous pleuritis containing fibroblasts and mixed chronic inflammatory cells
- Inflammatory myofibroblastic tumor
- Leiomyoma
- Leiomyosarcoma
- Localized pleural fibrosis:
- Occurs as pleural plaques, apical caps and nodular histiocytic hyperplasia
- Pleural plaques show a basketweave pattern of dense collagen
- Apical caps are scars of elastic tissue (more commonly seen with emphysema)
- Solitary fibrous tumor (SFT):
Additional references
