Neck hematoma is relatively rare and mostly a secondary consequence of infection, cervical spine trauma, great vessel trauma, iatrogenic injury associated with catheterization and angiography, or ingestion of a foreign body. Spontaneous neck hematoma also can occur as a result of thyroid or parathyroid extraglandular bleeding. The causative thyroid lesions include thyroid cyst, nodular goiter and subacute thyroiditis, whereas causative parathyroid lesions include adenoma, hyperplasia, cysts and cancer. Anticoagulation or hemorrhagic diathesis may be a predisposing factor in such cases [7].
Hemorrhage into a thyroid cyst is not uncommon, being usually palpable and quite tender, but bleeding into surrounding areas is rare because the thyroid capsule is relatively thick. Subacute thyroiditis following a viral illness can cause many systemic symptoms and a characteristically high sedimentation rate without any change in the level of serum calcium. Parathyroid bleeding is most often seen in patients with adenoma [8]. As neck hematoma can easily spread to the mediastinum and pleural space resulting in a life threatening condition, practitioners should be aware of other potentially critical sources of mediastinal hematoma, such as aortic dissection and mediastinal blood vessel rupture.
Extraglandular hemorrhage from a parathyroid adenoma is a very rare form of neck hematoma. In a review of the world literature and a series of cases from their center, Chaffanjon et al. identified only four hemorrhagic parathyroid adenomas out of a total of 692 cases [9]. Extracapsular parathyroid hemorrhage may occur when the parathyroid glands are enlarged due to tumors such as adenomas, primary or secondary hyperplasia, cysts, or cancers [10]. Expansion outside the capsule may be due to the fact that parathyroid glands containing tumors have relatively thin and weak capsules. As mentioned above, anticoagulation or hemorrhagic diathesis may aggravate the development of neck hematoma. In Case 1, the patient had been treated with an anticoagulant drug for internal jugular vein thrombosis.
The symptoms and signs of hematoma from a parathyroid tumor depend on the anatomical position of the tumor, the amount of bleeding and the increase or decrease in secretion of PTH accompanying the infarction and/or bleeding in the gland [10].
Cervical hematoma caused by a parathyroid tumor is characterized by painful swallowing, dysphagia, dyspnea, hoarseness, swelling of the anterior neck, or ecchymosis of the neck or chest [2, 10–13]. Severe compression of the pharynx or larynx can lead to narrowing of the airway, and may require emergency tracheostomy. Compression of the recurrent laryngeal nerve by a cervical hematoma can cause vocal cord paralysis. In particular, hoarseness, dysphonia and acute respiratory failure can be warning symptoms [14, 15].
Mediastinal hematoma or hemothorax due to intrathoracic parathyroid tumor bleeding is characterized by chest pain, cough, shortness of breath, or respiratory distress. Moreover, if the hemothorax is bilateral, it can induce acute severe respiratory failure [16]. The patient may also become hypotensive because of compression of the large vessels. Finally, mediastinal hematoma from a parathyroid tumor may mimic rupture of an aortic aneurysm [17, 18], as seen in Case 2.
Simcic and McDermott proposed three diagnostic criteria for hemorrhaging parathyroid tumors: acute neck swelling, hypercalcemia, and ecchymosis of the neck or chest [19]. After the introduction of these criteria, many cases lacking part of this triad were reported. As aortic dissection and blood vessel rupture can also cause sudden swelling and ecchymosis, hypercalcemia and the presence of a nodule behind the thyroid are the most specific symptoms of parathyroid bleeding. Sometimes, however, parathyroid adenoma can be non-functional for three reasons. First, there may be tissue necrosis secondary to cystic degeneration. Second, PTH may be secreted into the lumen of the cyst instead of the bloodstream. Third, the pressure caused by the hematoma may interfere with blood flow around the adenoma [20].
When encountering cervical and/or mediastinal hematoma, blood testing, which can detect hypercalcemia and a high level of intact PTH, is one of the key examinations for investigating the possibility of parathyroid adenoma bleeding. Imaging techniques such as ultrasonography, CT and MRI can identify nodular structures and differentiate solid tissue from cysts, but it may sometimes be difficult to distinguish between a thyroid nodule, a lymph node, and a parathyroid adenoma. However, scintigraphy (Tc-sestamibi imaging) can be used to distinguish between thyroid and parathyroid tissue and identify overactive parathyroids [4, 21]. The treatment of bleeding from a parathyroid adenoma requires surgical exploration and excision of the tumor after appropriate localization. The optimal timing of surgery remains controversial, however. For most previously reported cases, parathyroidectomy was performed within several weeks after the occurrence of hemorrhage. In some cases, however, the tumors were excised incompletely, and the recurrent laryngeal nerve was injured. Chaffanjon et al. proposed that if there are no severe compressive or hemodynamic symptoms, surgery should be performed more than 3 months after the occurrence of hemorrhage because the dissection then becomes as simple as for any other form of planned surgery [9]. Nevertheless, patient who presents with hemorrhage from a parathyroid tumor should not be observed for too long without excision of the tumor because there is a possibility that the hemorrhage will recur.
