Clinical pathologic correlation case 3: right facial swelling after tooth extraction

Abstract

Clinical Presentation

A 23-year-old man with a diagnosis of Hermansky-Pudlak syndrome presented to the emergency clinic, complaining of pain and swelling after a tooth extraction. Clinically, a painful swelling was identified to affect the right-side of the face. Panoramic imaging showed a diffuse asymmetric change in the cancellous and cortical bone pattern, extending from the mandibular right third molar region, mesially, crossing the midline, to the mandibular left canine region (Figure 1). The bone pattern alteration consisted of large and wide marrow spaces, bordered by remodeled cancellous bone trabeculae and admixed with multiple pinpoint radiolucent locules and multiple nutrient channel-like tubules; the latter was evident as channel-shaped discontinuities along the inferior mandibular cortex. Immediately adjacent to the affected region of the right mandibular body, the right mandibular foramen, right inferior alveolar canal, and right mental foramen were asymmetrically enlarged. Despite the bone pattern alteration, the normal anatomic shape and structure of the mandible was maintained and remained bilaterally symmetric to the unaffected left-side.

Differential Diagnosis

Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disorder that is associated with oculocutaneous albinism, bleeding diathesis, granulomatous colitis and, in certain subtypes, highly penetrant pulmonary fibrosis.¹ Currently, 11 recognized subtypes of HPS are linked to various mutations affecting the biogenesis or function of lysosome-related organelles.² Although these subtypes exhibit a range of clinical manifestations, none have been reported to cause jaw lesions akin to the current case. Nonetheless, patients with HPS may experience gingival bleeding, and prolonged bleeding following tooth extractions due to their bleeding diathesis. Therefore, it is essential to take appropriate precautions when treating patients with HPS.²

The differential for a relatively ill-defined noncorticated radiolucency in the posterior mandible is quite broad, but is suggestive of a locally aggressive lesion, malignancy, or a vascular lesion, which may mimic aggressive or malignant entities. Given the lesion's location within the tooth-bearing region of the jaws, both odontogenic and nonodontogenic entities should be considered. The differential diagnosis includes odontogenic myxoma, central giant cell granuloma, osteosarcoma, malignant peripheral nerve sheath tumor, and an intraosseous arteriovenous malformation.

Odontogenic myxomas are rare benign odontogenic tumors that have a predilection for the posterior mandible and are predominantly found in young adults, with an average age between 25 and 30 years.^3,4 Odontogenic myxomas are often associated with painless expansion and appear as a unilocular or multilocular radiolucency that may displace or cause resorption of teeth. Oftentimes, these lesions will show irregular or scalloped margins and larger lesions will classically have a “soap bubble”, or rarely a “sun-burst” radiographic appearance.⁴

Central giant cell granuloma (CGCG) is a localized, benign but sometimes aggressive osteolytic jaw lesion that most commonly occurs in female patients younger than 30 years.^5,6 CGCG develops almost exclusively in the jaws and most frequently occurs in the anterior mandible.⁵ Generally, CGCG presents with radiographic features of a benign entity, such as well-defined borders and slow-expansile growth. However, a minority of lesions display more aggressive features and may exhibit rapid growth, root resorption, and cortical perforation.⁵

Osteosarcoma is the most common malignancy to originate within bone, excluding hematopoietic neoplasms. Osteosarcomas of the jaws are distinct from those of the appendicular skeleton, in that they have an older age at presentation and longer median survival with rare metastases.⁷ Approximately 6% of all osteosarcomas arise within the jaws. Osteosarcomas of the jaws show no significant gender predilection with a peak in the 3rd-5th decade of life.⁴ Osteosarcomas show a variable radiographic appearance that can range from entirely radiolucent to radiopaque. The borders are oftentimes ill-defined and may display cortical expansion or destruction.⁷ The classic “sunburst” pattern may be seen in cases where a periosteal reaction is present as well as symmetrical widening of the periodontal ligament and “spiking” root resorption of adjacent teeth.⁴

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon aggressive tumor that arises from the cells of the peripheral nerve sheaths. Approximately 50% of MPNSTs are associated with neurofibromatosis type 1 (NF1) and the remainder are sporadic or associated with a history of radiation.⁸ While it would be uncommon in the head and neck region and in a patient without NF1, an MPNST was considered for this case, as they have rarely been reported to arise from trigeminal nerves and widen the inferior alveolar nerve canal⁹ as seen in the current case.

Benign vascular lesions, such as hemangiomas are common in the soft tissues of infants and children, however intraosseous hemangiomas, especially those of the jaws are exceedingly rare.¹⁰ These intraosseous “hemangiomas” usually represent either venous or arteriovenous malformations.⁴ Within the jaws, mandibular involvement is 3 times more common than maxillary involvement.¹⁰ Intraosseous vascular lesions tend to occur in the first 3 decades of life, and while most are asymptomatic, some have been associated with pain and swelling.^4,10 These lesions can present as a diagnostic challenge, as a wide range of presentations has been reported. The most common radiographic presentation is that of a multilocular radiolucent defect. They can also present with a “honeycomb” or “soap bubble” appearance and can have ill-defined borders.⁴ Larger malformations can cause cortical expansion and occasionally a “sunburst” pattern, mimicking osteosarcoma.⁴

Diagnosis and Management

CT angiography (CTA) confirmed the diagnosis of arteriovenous malformation (AVM), with the right facial and lingual branches of the right external carotid artery identified to be its predominant feeders (Figure 2). The trans-spatial facial AVM was centered on the right mandible and had multiple vascular channels piercing the mandibular body in multiple planes, which correlated to the locular-tubular bone pattern on panoramic imaging.

The patient was informed of the diagnosis of AVM and referred to neurosurgery for treatment. The AVM and its feeder vessels were embolized by polyvinyl alcohol particles one day prior to surgical resection. The surgical specimen showed multiple, dilated blood vessels of various sizes containing embolization material located within mature lamellar bone (Figure 3), histopathologic features indicative of AVM.

Discussion

Arteriovenous malformation (AVM) is a congenital, high-flow, vascular anomaly, comprising of a structurally abnormal mass of arteries and veins directly connected to each other without a capillary bed.^11-14 Most AVMs tend to become evident at puberty. However, some patients may not be aware of their lesion until the AVM suddenly enlarges after trauma, such as biopsy and tooth extraction, infection, or hormonal changes, such as pregnancy.^11,13 AVMs can be isolated lesions or associated with a syndrome,^11,13 but AVMs are not known to be a characteristic of Hermansky-Pudlak syndrome. AVMs of the facial region are typically found in the posterior mandible.^12,14 A 15-year retrospective study of 211 jaw AVMs found that bleeding was the most common chief complaint.¹² Due to its high-flow nature, bleeding from AVM can be catastrophic and life-threatening.^11,12,14 While the clinical presence of a palpable thrill and an audible bruit associated with an intraoral swelling can raise suspicion of AVM, diagnostic imaging is preferred over biopsy for diagnosis to minimize the risk of lethal exsanguination.^11,13,14

On panoramic imaging, mandibular AVMs are characterized by 3 features.^12,15 First, the shape of the mandible on the affected side looks bilaterally symmetric to the shape of the mandible on the unaffected side. In other words, gross anatomic contours of the mandible are preserved. Second, the affected mandible is associated with an asymmetrically enlarged and widened, neurovascular canal and/or foramen, which guides identification of the feeder vessels to the AVM and represents the malformed vasculature. Third, the cortical and cancellous bone pattern of the affected mandible consists of a diffuse mix of radiolucent locules and tubules, representing the haphazard arrangement of multiple tortuous blood vessels intersecting each other and piercing bone. This third characteristic reflects the “bag of worms” appearance of AVM on advanced imaging, such as CT / MR angiogram, which is used to confirm the diagnosis, map the lesion for surgery, and monitor treatment response.^11,13,14