Intravascular Papillary Endothelial Hyperplasia (Masson’s Tumor) of the Submandibular Gland: A Case Report

Abstract

Intravascular papillary endothelial hyperplasia (IPEH), a rare benign endothelial vascular lesion related to thrombosis, generally develops in fingers, trunk, head, and neck. Nevertheless, it has been rarely reported in the salivary gland. In this article, we report a case of IPEH of the right submandibular gland in a 37-year-old female whose initial impression was sialadenitis secondary to sialolithiasis. To date, our case may be the first well-documented report of IPEH in the submandibular gland. The patient underwent ablation of the submandibular gland, and no evidence of recurrence was found during follow-up.

Introduction

Intravascular papillary endothelial hyperplasia (IPEH), also known as Masson’s tumor, is a rare, benign endothelial vascular lesion, characterized by reactive proliferation of endothelial cells with papillary growth related to obstructive thrombosis. ^{1 -5} It was first described by Pierre Masson in 1923 with the term “vegetant intravascular hemangioendothelioma.” ^{6 -9} Most authors emphasized IPEH may mimic low-grade angiosarcoma as its endothelial papillary proliferation. ^{1 -8,10 -12} Intravascular papillary endothelial hyperplasia occurs most commonly in fingers, trunk, head, and neck, with a predilection for skin and subcutaneous tissue of the scalp and face but can also develop in any other blood vessel. ^{1,2,4 -12} Intravascular papillary endothelial hyperplasia has been rarely reported in the salivary gland. To the best of our knowledge, few cases of parotid Masson’s tumor had been documented, and only one case of IPEH manifesting as a submandibular mass was presented by Kim et al. ⁶ In this article, a new case of Masson’s tumor located in the submandibular gland is presented and we well documented the image features of this tumor.

Case Presentation

A 37-year-old female patient had intermittent swelling of her right upper neck below the mandible for about 2 months. The swelling sensation was noticed after meals. Otherwise, she denied fever or local tenderness during these weeks. She denied major trauma or medical history in the past. The only significant personal history is major depression under antidepressant agents for years.

On examination, a nontender firm mass at the right submandibular space was found, measuring about 2 × 1 cm, without local heat or erythema. There was no other palpable cervical lymphadenopathy, nor sialolithiasis or purulent exudate at the mouth floor. Fiberscopy showed nothing unusual of nasopharynx, oropharynx, hypopharynx, and larynx. Neck sonography revealed a 1.54 × 1.01 × 1.09 cm, hypoechoic, lobulated and spongiform mass in the right submandibular gland (Figure 1). Fine needle aspiration had been performed and the thin layer cytology report showed presence of some fibrinous material and mixed inflammatory cells, and absence of malignant cells. A head and neck computed tomography scan also disclosed an irregular rim-enhancing hypodense lesion measuring about 2 cm in maximal diameter in the right submandibular gland, and a tiny calcification within the lesion was detected as well (Figure 2).

Figure 1.

Neck sonography: a 1.54 × 1.01 × 1.09 cm, hypoechoic, lobulated and spongiform mass in the right submandibular gland.

Figure 2.

Computed tomography (CT) scan: an irregular rim-enhancing hypodense lesion measuring about 2 cm in maximal diameter in the right submandibular gland, with a tiny calcification within the lesion.

The initial impression was sialadenitis secondary to sialolithiasis with intraglandular abscess or submandibular gland tumor. Surgical intervention was indicated, and thus the patient received ablation of the right submandibular gland (Figure 3). The final pathology report unveiled no conspicuous mass formation on section. On microscopy, the sections showed a picture of papillary endothelial hyperplasia (size 0.9 cm), composed of some papillary structure lined by plump endothelial cells without atypia (Figure 4A). The endothelial cells were positive for CD31 (Figure 4B), and negative for CD34 and D2-40 immunostains. The pathological presentation was compatible with Masson’s tumor. Thrombi formation was also present. Few foci of chronic inflammation were seen in the salivary gland background, but there was no abscess formation. There was also no evidence of malignancy in the sections examined.

Figure 3.

The right submandibular gland, measuring 4 × 3 × 2.2 cm.

Figure 4.

(A) Papillary endothelial hyperplasia, composed of some papillary structure lined by plump endothelial cells (arrows) with thrombi formation (star) (hematoxylin and eosin [H&E], ×20). (B) The endothelial cells positive for CD31 (CD31, ×100).

The postoperative course was smooth and uneventful. No specific symptoms nor signs of recurrent swelling were found during outpatient clinic follow-up 1 month after the operation.

Discussion

In 1923, “vegetant intravascular hemangioendothelioma” was named by Pierre Masson to first describe a benign vascular neoplasm with an unusual entity of extensive proliferation of endothelial cells with papillary formation within the vascular lumen. ^{1 -6,9,10,12} After this time, various synonyms, including intravenous atypical vascular proliferation, intravascular angiomatosis, intravascular endothelial proliferation, Masson’s pseudoangiosarcoma, Masson’s intravascular hemangioendothelioma, and reactive papillary endothelial hyperplasia have been used to describe this lesion. ^4,7,12 There is a slight predilection for females, with an incidence ratio 1.3:1.0 been reported, and it occurs at any age ranging from 9 months to 80 years. ^1,2,4,6,9,10

The first case proposed by Masson was a 68-year-old man with an inflamed hemorrhoidal plexus. ^{1 -3,9,10} Nevertheless, IPEH can occur in any blood vessel of the body and has a predilection for the deep dermis and subcutis of the head, neck, trunk, and upper extremities. ³ Cases of various affected sites of the head and neck region, for instance, oral mucosa, lips, tongue, gingiva, skin of the scalp and face, and orbit have been reported. ¹⁰ The presentation of IPEH in the salivary gland is relatively rare, with a majority in the parotid gland. ^1,7,10

On reviewing the accessible literature on Masson’s tumors of salivary gland, only 4 cases were reported to date (Table 1). ^1,6,7,10 Of the 5 patients including ours, the age ranged from 18 to 70 years, with a mean age of 41.4 years. There were 4 (75%) females and only 1 (25%) male. Parotid gland was the most commonly affected site (3 cases, 60%). Patients’ symptoms vary from painless to painful swelling. The diameter of the tumors ranged from 2 to 5 cm (mean 2.7 cm). Two of the cases were first diagnosed with pleomorphic adenoma, and another 2 had the initial impression of sialadenitis secondary to sialolithiasis. However, except for our case, none of the patients received sonographic examination and fine needle aspiration for cytology. As for the treatment, all cases underwent total resection.

Table 1.

Overview of Published Cases of Intravascular Papillary Endothelial Hyperplasia in the Salivary Glands.

Authors/year of publication	Age/sex	Site	Presentation	Size (cm)	FNAC	Clinical impression	Management
Kim et al 6 /2007	18/Female	Submandibular region	Painful swelling	5	NA	Obstructive sialadenitis secondary to a lucent sialolithiasis	Resection of the mass along with the submandibular gland
Mokhtari et al 7 /2011	39/Male	Parotid gland	Painless swelling	NA	NA	Pleomorphic adenoma	Partial resection of the parotid gland
Mignogna et al 10 /2016	70/Female	Parotid gland	Painless swelling with facial asymmetry	2 × 1	NA	Pleomorphic adenoma	Extracapsular dissection
Carta et al 1 /2018	43/Female	Parotid gland	Mildly painful swelling	2.3	NA	NA	Subtotal parotidectomy
Our case	37/Female	Submandibular gland	Painless swelling	1.54 × 1.01 × 1.09	Presence of some fibrinous material and mixed inflammatory cells	Sialadenitis secondary to sialolithiasis	Ablation of the submandibular gland

Abbreviations: FNAC, fine needle aspiration cytology; NA, not available.

Kim et al described a case of IPEH located in the submandibular space of an 18-year-old female, manifesting as a submandibular tumor. As description, the Masson’s tumor was adherent to the submandibular gland with a clear separation. In this case, relatively, IPEH within the submandibular gland is presented.

The pathogenesis remains poorly understood and is under debate, and thrombus formation plays a role in several hypotheses of different point of view. As the first theory, Masson regarded IPEH as a neoplasm resulting from endothelial proliferation that causes subsequent thrombosis. ³ On the contrary, Clearkin claimed that organization of a thrombosis contributes to the reactive papillary formation of endothelial cells, which is the more accepted concept at present. Also, it had been proposed by Levere et al that basic fibroblast growth factor (bFGF) released by macrophages due to traumatic vascular stasis stimulates endothelial cell proliferation, and they reported an increase of bFGF in cases of IPEH. ¹⁰

Intravascular papillary endothelial hyperplasia has been classified into 3 types by Hashimoto et al: (a) a pure (primary) form that arises in dilated vessels, being the most common type; (b) a mixed (secondary) form that occurs in preexisting vascular abnormalities, such as varices, hemangiomas, lymphangiomas, pyogenic granulomas, and arteriovenous malformations; and (c) the undermined type, a rare extravascular hemangioma developing in the bed of an organizing hematoma. ^3,10,11

Microscopic examination is essential for the diagnosis of IPEH. The histological differentiation includes angiosarcoma, hemangioma, vascular malformation, pyogenic granuloma, epithelioid hemangioendothelioma, Kaposi sarcoma, and other vascular lesions. ^4,8 Among this, angiosarcoma as a major differential diagnosis is emphasized by most authors. ^{1 -8,10 -12} Regarding IPEH, it typically shows an intravascular proliferation of papillary structures covered by no more than 2 layers of endothelial surfaces with connective tissue core within, which are often associated with thrombus formation. ^2,3,10,11 Cellular anaplasia, necrosis, and nuclear atypia are basically absent. Moreover, the proliferation of IPEH is exclusively limited to the intravascular spaces, whereas angiosarcoma may spread outside the vessels with more than 2 endothelial cell layers coverage of papillae. Immunohistochemical markers help the identification of the endothelial origin. Masson’s tumors are usually positive for CD31, CD34, α-SMA, factor VIII, and XIIIa. ^5,8,11 CD31 and CD34 are the most sensitive due to frequent expression by vascular endothelium. Comparatively, the overexpression CD105 (endoglin) indicating tumor angiogenesis may assist in differentiating angiosarcoma from IPEH.

Total resection is the proper way for treatment of IPEH, and the prognosis is satisfying. Recurrence may only occur in the case of incomplete resection. ^6,8 There was no evidence of regional or systemic angiopathy associated with Masson’s tumor to date. In conclusion, we reported a rare case of Masson’s tumor located in the submandibular gland, which was uneventfully removed without evidence of recurrence. It is crucial to correctly diagnose this benign vascular lesion according to its histopathological characteristics and distinguish it from angiosarcoma for appropriate treatment planning.