Intravascular Papillary Endothelial Hyperplasia
Key Points
Intravascular papillary endothelial hyperplasia is a vascular lesion that usually arises in veins or arteries
It is a reactive lesion representing an unusual form of organizing thrombus rather than a neoplastic process
IPEH may occur as a primary lesion developing within the lumen of a distended vessel or associated with other vascular lesions or in a hematoma
The pathogenesis is not understood, but may involve an autocrine loop of endothelial basic fibroblast growth factor secretion stimulating endothelial cell proliferation
On the eyelid, lesions generally present as a bluish to reddish, painless, firm, mobile swelling, or nodule
Treatment is surgical by opening the vessel and removing the mass, or by excision of the involved portion of the vessel
The prognosis is usually excellent following surgical resection
Intravascular papillary endothelial hyperplasia (IPEH), also known as Masson tumor, is a vascular lesion of the skin and subcutaneous tissue that usually arises in veins or arteries situated either in the dermis or subcutis.1,2 It consists of a reactive proliferation of endothelial cells occurring within an organizing thrombus.3 The condition was first described in 1923 by Pierre Masson in a 68-year-old man with a painful, nonhealing subcutaneous lesion with endothelium-covered papillae and trabeculae that obstructed a vein. He proposed that this lesion was a peculiar angiosarcoma-like lesion arising as a primary process resulting from benign proliferation of endothelial cells with secondary thrombosis and fibrin deposition. He termed it hemangioendotheliome vegetant intravasculaire, believing it to be a true neoplasm.4 Later, Clearkin and Enzinger recognized it as a reactive lesion representing an unusual form of organizing thrombus rather than a neoplastic process. They introduced the name IPEH.
IPEH occurs most commonly on the extremities and in the head and neck, and only rarely in the ocular adnexa and orbit.5,6,7,8,9,10,11,12 When the eyelid is involved, 60% of lesions occur in the upper eyelid, 20% in the lower eyelid, and 20% in the medial or lateral canthal angles.
IPEH may occur as a primary lesion developing within the lumen of a distended vessel or associated with other lesions,13 and they have been classified into several types. Type I represents the primary (pure) form, characterized by the presence of the lesion within a distended vessel. Type II, or secondary (mixed) form, shows an IPEH in a preexisting vascular lesion such as a hemangioma or pyogenic granuloma.14,15,16 Type III is rare and indicates an extravascular location of the lesion in a hematoma often following recent trauma. These have been described in the adrenal and parotid glands, heart, intestine, kidney, liver, retroperitoneum, spine, maxillary sinus, and orbit.16,17,18,19,20,21,22
Etiology and Pathogenesis
The precise etiology and physiopathology of IPEH are incompletely understood. It is considered to be a reactive process, and not a true neoplasm, characterized by exuberant endothelial proliferation, mostly within the lumen of blood vessels.25 It was proposed that this reactive process could be related to endothelial trauma or inflammation and subsequent thrombus formation.3,14,15 However, in a review of 314 cases of IPEH from the literature, Pins et al26 found that only 4% were related to known trauma.
Levere et al27 studied five pooled cases of IPEH by Northern blot and immunoblot and showed a 5- to 10-fold increase in basic fibroblast growth factor transcripts and a 10- to 20-fold increase in immunoreactive basic fibroblast growth factor protein compared to non-IPEH organizing thrombi and cavernous hemangiomas. The results suggested that the pathogenesis of IPEH might involve an autocrine loop of endothelial basic fibroblast growth factor secretion stimulating endothelial cell proliferation.
Clinical Presentation
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