Myxoid intravascular papillary endothelial hyperplasia of the hard palate. A unique case?

Abstract

Intravascular papillary endothelial hyperplasia (IPEH) is an uncommon reactive lesion that shares some features with, and thus can be misdiagnosed as, hemangiosarcoma. Most are associated with a thrombus. Oral cases are rare, only 105 being reported through 2020, and only one has been reported in the hard palate. The stroma of the papillary structures has been described as fibrous, hyalinized, or hypocellular and hyalinized. Presented here is a case of IPEH of the hard palate with no associated thrombus and a myxoid stroma of the papillary structures and wall. The significance of the myxoid stroma is that it has the potential to confound the diagnosis and, by analogy to odontogenic and other myxomas, for concern regarding a tendency to recur.

Highlights

  • Intravascular papillary endothelial hyperplasia (IPEH) is a reactive lesion that occurs rarely in the oral cavity.

  • Only one case has been reported in the hard palate, and none with a myxoid stroma.

  • Presented here is a case of the hard palate with myxoid stroma of the papillary structures and wall.

  • Myxomas tend to recur, but this is not applicable to this myxoid IPEH because it is not a neoplasm.

  • There was no recurrence of the lesion 5 months after surgical removal.

Introduction

In 1923, Masson [ ] described an intravascular papillary proliferation of endothelium that shares histologic features with, and thus could be mistaken for, hemangiosarcoma. In subsequent reports it was shown that the lesion is usually associated with a thrombus, seldom recurs after excision, has a low rate of proliferation, and rarely has a necrotic area, features which, together with the intravascular location, distinguish it from hemangiosarcoma [ ]. In 1976, Clearkin and Enzinger [ ] considered it to be a reactive lesion and introduced the term intravascular papillary endothelial hyperplasia (IPEH). Recurrence is rare when the lesion is excised with clean margins 3 .

Although cases of IPEH have occurred in numerous tissues and organs, it is an uncommon lesion overall, and cases of the oral cavity are rare [ ]. In the 105 cases of oral IPEH compiled in an exhaustive review including 20 new cases by Vieira et al. [ ], the hierarchy of frequency of soft tissue sites in descending order was lower lip, buccal mucosa, tongue, upper lip, labial commissure, palate, and floor of the mouth. Four cases also occurred as intraosseous lesions of the mandible.

To our knowledge, only three cases of IPEH of the palate have been reported previously, two in the soft palate [ , ], and one in the hard palate [ ]. In addition, the stroma or cores of the papillary structures in oral cavity cases of IPEH have been described as fibrous [ , ], hyalinized [ , , , ], and hypocellular and hyalinized [ , ], but not myxoid. A case of IPEH of the hard palate with a myxoid stroma is reported here.

Case report

A small red lesion was discovered in the right hard palate during a periodontal examination of a 73-years-old man in the Dental Clinic of the Washington, DC Veterans Affairs Medical Center. The patient reported that it was asymptomatic and that he “had been feeling it with his tongue for about one year”, with no change in size, and no history of trauma. He was referred to the Oral and Maxillofacial Surgery Section for a biopsy of the lesion. The surgeons described it as 4 × 6 mm, purple and pink, raised, smooth, movable and fluctuant. The clinical differential diagnosis included mucocele, mucoepidermoid carcinoma, and pleomorphic adenoma. The medical history included allergic rhinitis, adenomatous polyp of colon, seborrheic keratosis, and venous stasis. Medications were Atorvastatin and Loratadine.

Under local anesthesia, the lesion was excised, immersed in neutral buffered 10% formalin, and delivered to the Pathology and Laboratory Service Anatomical Pathology Laboratory for routine processing. Paraffin sections were stained with hematoxylin and eosin (H&E). The surgical site healed uneventfully. There was no sign of persistence or recurrence of the lesion at a follow-up periodontal examination five months after the surgery.

Histologically ( Fig. 1 A and B), the specimen consisted of collagenous tissue harboring a few mostly mucous salivary glands and covered with keratinized stratified squamous epithelium. Near the center there were two large and several small papillary structures lying within and attached to a dilated vascular space. Collagen in the core of the largest structure consisted of scattered, very fine fibrils, giving it a pale, myxoid appearance. No thrombus and no signs of malignancy, such as necrosis, cellular or nuclear pleomorphism, or numerous mitoses, were seen. The preliminary diagnosis was a “burnt-out” Masson vascular tumor, or IPEH. Immunohistochemistry and special stains were then employed to confirm the diagnosis and to further explore the impression of a myxoid change in the stroma of the papillary structures and wall, as follows.

Fig. 1
Photomicrographs of sections with routine stains (A, B) and subjected to immunohistochemistry (C, D). A . Survey view. Tumor is at the center of the tissue specimen. Note keratin surface layer and blunt rete ridges of overlying epithelium. B . Detail of section in (A). Part of the wall and the larger of two intravascular papillary projections (arrow) in the dilated vessel lumen (v) hvs a myxoid-appearing stroma. Note also the minor salivary glands (g) with mucous acini. C, CD31. D, CD34. Endothelium is stained brown. Stains: (A, B), Hematoxylin and Eosin; (C, D), Reaction product of H 2 0 2 /DAB. Magnification bar = 500 μm (A); 200 μm (B–D).
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Aug 14, 2022 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Myxoid intravascular papillary endothelial hyperplasia of the hard palate. A unique case?
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