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Soft tissue

Vascular

Nonneoplastic

Papillary endothelial hyperplasia

Authors: Laura Warmke, M.D., Jeanne Meis, M.D.

Editorial Board Member: Nasir Ud Din, M.B.B.S.

Deputy Editor-in-Chief: Borislav A. Alexiev, M.D.

Last author update: 15 May 2023

Last staff update: 15 May 2023

Copyright: 2003-2024, PathologyOutlines.com, Inc.

PubMed Search: Papillary endothelial hyperplasia

Table of Contents

Cite this page: Warmke L, Meis J. Papillary endothelial hyperplasia. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/softtissuemasson.html. Accessed December 21st, 2024.

Definition / general

Benign, reactive proliferation of endothelial cells (nonneoplastic)
First described in 1923 by French physician Pierre Masson, who described an atypical papillary endothelial proliferation in an ulcerated hemorrhoid, which was originally considered to be a vascular neoplasm, in a 68 year old man
Recognized as a reactive process in 1932 by Henschen
Term intravascular papillary endothelial hyperplasia was first used by Clearkin and Enzinger in 1976 (Arch Pathol Lab Med 1976;100:441)
3 types: primary (pure form) arising in a dilated vessel, secondary (mixed form) arising in a pre-existing vascular lesion and rare extravascular form typically arising in hematoma (Am J Dermatopathol 1983;5:539)

Essential features

Benign intravascular proliferation of reactive endothelial cells, forming numerous papillae most often lined by a single layer of plump endothelial cells
Associated thrombotic material is frequently present
Small, well circumscribed lesion without necrosis, marked cytologic atypia or infiltrative growth pattern

Terminology

Also known as Masson tumor
Intravascular papillary endothelial hyperplasia (IPEH)

Epidemiology

Slight female predominance (1.3:1) (Ear Nose Throat J 2021 Jun 10 [Epub ahead of print])
No known ethnic predilection
Average age: 31 years (range, 9 months to 78 years) (Am J Dermatopathol 1983;5:539)

Sites

Intravascular location is most common
Can occur in any blood vessel
Most commonly in subcutis of fingers (Am J Dermatopathol 1983;5:539)
Frequently in subcutis of head, neck and upper extremities
Does not tend to involve the overlying skin

Pathophysiology

Pathogenesis still unknown
Favored to be an exuberant form of organizing thrombus rather than a primary tumor, arising in the context of venous stasis
Development takes place in several stages, including endothelial cell growth within a thrombus, production of collagenases by the endothelial cells, partial digestion of the thrombus and the formation of papillary structures (Cir Esp 2017;95:235)
Hypoxia inducible factor 1 alpha (HIF1α) and vascular endothelial growth factor (VEGF), proteins associated with thrombus remodeling and angiogenesis, are highly expressed in cellular cores (Int J Clin Exp Pathol 2013;6:2912)
Elevation of basic fibroblast growth factor (bFGF), which is released by macrophages due to traumatic vascular stasis, stimulates endothelial cell proliferation (J Hand Surg Am 1994;19:559)

Etiology

May represent an alteration in the process of thrombosis
Thrombus hypothesis: thought to result from hyperplastic endothelial proliferation caused by development and recanalization of a thrombus within a blood vessel
Slight female predominance may have hormonal influence (Case Rep Dent 2014;2014:934593)
Preceding trauma has been reported in occasional patients (Am J Dermatopathol 1983;5:539)

Clinical features

Slow growing mass lesion or swelling
Firm, subcutaneous nodule or papule
Ovoid, rounded or lobulated shape
Superficial location
Bluish or reddish discoloration of the overlying skin
May be tender or painless (Dermatol Online J 2016;22:13030)
Often incidental finding within thrombosed dilated blood vessels or vascular tumors

Diagnosis

Nonaggressive features on imaging studies
Final diagnosis on histologic examination of excision specimen
Assess for pre-existing vascular lesion (secondary form) (Arch Pathol Lab Med 1993;117:259)

Radiology description

Ultrasound
- Well circumscribed mass
- Lobulated
- Hypoechoic
MRI
- Well defined lobulated lesion
- High T2 signal peripherally (Skeletal Radiol 2016;45:1467)
- Variable central enhancement and signal intensity
- Majority (73%) associated with a dominant vessel (Skeletal Radiol 2016;45:1467)

Radiology images

Images hosted on other servers:

Ultrasound

CT scan

Prognostic factors

Benign clinical course
Secondary form follows course of pre-existing vascular lesion
No patient with pure form had a recurrence (Am J Dermatopathol 1983;5:539)

Case reports

19 year old man with enlarging mass in right shoulder (Arch Pathol Lab Med 1993;117:259)
29 year old woman with cecal mass (Surg Case Rep 2022;8:179)
32 year old woman with submucosal vulvar lesion (Dermatol Online J 2016;22:13030)
37 year old woman with submandibular gland lesion (Ear Nose Throat J 2021 Jun 10 [Epub ahead of print])
65 year old woman with mandibular lesion (J Craniofac Surg 2022;33:e431)

Treatment

Treated by simple local excision

Clinical images

Contributed by Mark R. Wick, M.D.

Tongue lesion

Images hosted on other servers:

Oral mucosa

Gross description

Well circumscribed lesion
Purplish red multicystic mass
Associated hemorrhage and clotted blood
May be surrounded by a fibrous pseudocapsule
Small lesion (usually < 5 cm) (Dermatol Online J 2016;22:13030)

Gross images

Images hosted on other servers:

Submandibular mass

Small bowel

Microscopic (histologic) description

Papillary structures within vascular spaces (Case Rep Pathol 2020;2020:4348629)
Numerous papillae with cores of fibrin or fibrous connective tissue
Papillae lined by a single layer of plump endothelial cells
Piling up of endothelial cells is unusual
Slight nuclear atypia and rare mitotic figures may be seen
Associated thrombi of different sizes and stages of organization often present
Absence of tissue necrosis
No atypical mitotic figures
No extensive high grade cytologic atypia
Mixed form arises in vessels with abnormalities such as arteriovenous malformations, hemangiomas and pyogenic granulomas (Cir Esp 2017;95:235)
Extravascular form associated with trauma related hematomas

Microscopic (histologic) images

Contributed by Laura Warmke, M.D.

Cavernous hemangioma

Organized thrombus

Subcutaneous vessels

Dilated vessel

IPEH involving vessel

Calcification

Papillary structures

Numerous papillae

Reactive endothelial hyperplasia

Numerous papillary structures

CD31

CD34

Virtual slides

Images hosted on other servers:

Hemangioma with IPEH

Subcutaneous abdominal wall lesion

Cytology description

Cytologic features are varied and not diagnostic (Acta Cytol 2012;56:199)
Hemorrhagic and fibrinous background
Scattered spindle cells with capillary network
Hyaline cores surrounded by lesional cells (Acta Cytol 1990;34:175)
No necrosis or marked cytologic atypia
Rare mitotic figures may be present but no atypical forms

Positive stains

Negative stains

Electron microscopy description

Papillae lined by nonstratified layer of plump endothelial cells
Fibroblasts and pericytes in underlying stroma
Ultrastructure and organization closely resembles granulation tissue (Cancer 1978;42:2304)

Electron microscopy images

Images hosted on other servers:

Plump endothelium

Videos

Masson "tumor"

Sample pathology report

Skin and subcutaneous tissue, left index finger, mass, excision:
- Intravascular papillary endothelial hyperplasia (see comment)
- Comment: Sections show a dilated vessel centered in the superficial subcutaneous tissue with an associated intravascular proliferation of reactive endothelial cells, forming numerous papillary structures lined by a single layer of plump endothelial cells. The lesion is well circumscribed with a fibrous pseudocapsule and completely excised. No necrosis, no areas of infiltrative growth, no mitotic figures and no marked cytologic atypia is identified. Immunohistochemical stains for CD31 and ERG highlight the reactive endothelial cells, while CK cocktail is negative. These results support the diagnosis above. All control slides stained appropriately.

Differential diagnosis

Pyogenic granuloma (lobular capillary hemangioma):
- Often arises in oral mucosa
- May be associated with pregnancy
- Proliferation of granulation tissue
- Inflammatory infiltrate, often composed of neutrophils, is present
Arteriovenous malformation:
- Admixture of different vessels, including capillaries, veins and arteries
- Usually forms a larger mass involving deeper soft tissue
- Often have associated benign adipose tissue
- Extends beyond the confines of a single vessel (not intravascular)
Thrombus:
- Composed of layers of platelets and fibrin
- Alternating layers of red blood cells can form lines of Zahn
- No papillary structures within vascular space
Angiosarcoma:
- Solid areas of tumor growth
- Tumor necrosis common
- Stacking or piling up of endothelial cells
- Marked cellular pleomorphism
- Infiltrative growth pattern
- Irregular, anastomosing vascular channels
- Mitotic figures common, including atypical forms

Additional references

Goldblum: Enzinger & Weiss's Soft Tissue Tumors, 7th Edition, 2019

Board review style question #1

What is another name for intravascular papillary endothelial hyperplasia?

Arteriovenous malformation
Hemangioma
Masson tumor
Organizing thrombus

Board review style answer #1

C. Masson tumor. Masson tumor is another name for intravascular papillary endothelial hyperplasia, which is currently favored to represent a reactive process as opposed to a true neoplasm. Hemangioma and arteriovenous malformation represent a true neoplasm or malformation respectively. Most cases of Masson tumor are associated with an organizing thrombus.

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Reference: Papillary endothelial hyperplasia

Board review style question #2

What is the most common anatomic location for papillary endothelial hyperplasia to arise?

Bone
Deep soft tissue
Heart
Subcutaneous tissue of fingers

Board review style answer #2

D. Subcutaneous tissue of fingers. The most common anatomic location for papillary endothelial hyperplasia is the subcutaneous tissue of the fingers. The heart, deep soft tissue and bone are all unusual locations for this entity.

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Reference: Papillary endothelial hyperplasia

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