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Idiopathic acquired ectopic auricular ossification: a case report and review of the literature.


A petrified auricle is a rare condition in which one or both auricles become stony hard and incapable of being folded. It is caused by local factors (e.g., physical trauma, inflammation, or frostbite), and it is associated with several systemic factors (e.g., various endocrinopathies). Histologically, this phenomenon usually occurs secondary to calcification; rarely is ossification responsible. (1)

We report the case of a patient with auricular ossification, and we review the relevant literature.

Case report

A 72-year-old woman presented with stiffness of the left auricle. The onset of her condition had occurred several months earlier, and the rigidity had gradually progressed since then. The patient also reported the recent onset of a dull pain, especially when she was trying to sleep. She could not recall any contributory event, and she denied any history of relevant trauma, inflammation, or frostbite. Her medical history was significant for previously diagnosed osteoporosis, for which she had taken calcium and vitamin D supplementation for 8 years. She had also been taking medication for diabetes mellitus, hypertension, and angina pectoris for more than 10 years, and these diseases were under control.

On physical examination, the patient's left ear was slightly thickened (figure 1) and rigid, especially around the cavitas conchalis, and it could not be folded. She reported pain when local pressure was applied to the area. The external auditory canal was not stenotic, and the tympanic membrane was normal. The overlying skin did not exhibit any cutaneous pathology. The right ear was not affected.

Laboratory evaluations included a complete blood count, a basic electrolyte panel, and measurements of serum calcium, phosphorus, basic liver enzymes, and thyroid and parathyroid hormones. The results indicated mild anemia and a slight prolongation of both the prothrombin time and the activated partial thromboplastin time. Calcium and phosphorus levels were within normal ranges.

Computed tomography (CT) of the temporal bone demonstrated a bony opacity in the left auricular cartilage; minute radiolucent air spaces seen within the opacity were indicative of true bone formation (figure 2). To confirm this diagnosis, a piece of the left auricular cartilage was obtained through a small incision for histology, and the specimen demonstrated spicules of lamellar bone with osteocytes (figure 3).

In the absence of an inciting local factor, we were unable to determine the exact cause of the petrification in this case. Since no treatment was advisable for this patient's particular condition, she was monitored with regular checkups. Throughout follow-up, she continued to complain of mild pain, but the ossification did not show any signs of progression.


The auricular cartilage is an elastic substance that provides flexibility to the auricle. It does not normally have a tendency to ossify or calcify. Bochdalek reported the first case of petrified auricle in a male cadaver in 1866. (2) Since then, about 140 cases of petrified auricle have been recorded.

Petrification of the auricle has been attributed to ectopic ossification, dystrophic calcification, and metastatic calcification:

* Ectopic ossification involves new bone formation in tissue that normally does not ossify.

* Dystrophic calcification occurs when calcium is deposited in damaged tissue in a patient with normal serum calcium and phosphate levels.

* Metastatic calcification is caused by a disturbance in calcium metabolism. (1,3)

Ossification as a cause of petrified auricle is much more rare than calcification. (1) To the best of our knowledge, only 18 cases of auricular ossification have been previously reported in the literature. (1-11) The only way to diagnose auricular ossification is by identifying lamellar bone on histology. (10)

Ectopic ossification can be congenital or acquired. (6,12) The congenital type is seen in rare syndromes, including congenital plaque-like osteomatosis, Albright hereditary osteodystrophy, fibrodysplasia ossificans progressiva, and osseous heteroplasia. (6) The more common acquired form usually occurs after musculoskeletal trauma (e.g., fracture, joint dislocation, or soft-tissue trauma) or orthopedic surgery (e.g., hip, knee, or shoulder arthroplasty). (6,12) Another type of acquired ectopic ossification occurs after an injury to the nervous system, such as damage to the spinal cord; in such a case, the ossification can occur without any direct trauma to the lesion site. (12)

The pathogenesis of ectopic ossification is different from that of dystrophic and metastatic calcification. Ectopic ossification is believed to occur as the result of the transformation of primitive cells of a mesenchymal origin, which are present in the connective tissue septa, into osteoprogenitor cells. (5) Chalmers et al proposed that three conditions are needed for this transformation to occur: the presence of inducing agents, osteogenic precursor cells, and a permissive environment. (13) Bone morphogenetic protein is believed to be the causative agent that induces differentiation of mesenchymal cells into osteoprogenitor cells. (1,12)


The most common cause of auricular ossification and calcification is frostbite. (3,14) Gordon reviewed 119 cases of calcification reported in the literature and found that local factors were responsible for 44 cases (frostbite accounting for 29 of these) and systemic diseases were responsible for 34 cases (Addison disease accounting for 14); the causes of the remaining 41 cases were unknown. (14) Local causes other than frostbite include trauma, inflammation, chondritis, and perichondritis. Systemic factors, in addition to Addison disease, include hyperparathyroidism, hypopituitarism, hyperthyroidism, and diabetes. (3,8,10)



Our patient had taken calcium and vitamin D supplementation for the previous 8 years as a treatment for osteoporosis, and she was also being treated for diabetes and hypertension. It is known that both diabetes and a calcium-phosphate imbalance can contribute to ectopic ossification, but it is not known for certain if they are direct causes. As mentioned earlier, the pathogenesis of ectopic ossification requires a local event that initiates the differentiation of mesenchymal cells into osteoprogenitor cells. However, our patient denied any type of physical trauma or frostbite, so we were unable to ascertain the cause of her condition.

Symptoms of petrified auricle are correlated with the extent of the calcification or ossification. Localized lesions are more common than diffuse lesions. Lister analyzed 65 reported cases of auricular calcification and ossification of the auricle. (4) Of these 65 patients, only 3 presented with symptoms that could be directly attributed to the rigidity of the auricle. In each of these 3 patients, the complaint was one of discomfort on reclining as a result of pressure on the hard pinna.

In view of the rarity of petrified auricle, information regarding its treatment is limited. Some authors have recommended surgical intervention or wedge resection in cases of severe discomfort. (3,4,7,8) However, the trauma of surgery itself may actually aggravate the condition. (12) Also, excision may be difficult in a diffusely ossified auricle. Bisphosphonates and some nonsteroidal antiinflammatory drugs (indomethacin and ibuprofen) have been used by orthopedic surgeons for prophylaxis and treatment of ectopic ossification in the musculoskeletal system. (12) Also, ethane-1-hydroxy-1,1-diphosphate (EHDP) is known to have an effect on preventing or arresting ectopic ossification. (12)

Additional reporting and experience with this rare disease may further elucidate its pathophysiologic mechanisms and treatments.


(1.) DiBartolomeo JR. The petrified auricle: Comments on ossification, calcification and exostoses of the external ear. Laryngoscope 1985;95 (5):566-76.

(2.) Bochdalek V. Physiologische Verknocherung der Aurecula. Prag Vierteljahrschr 1866;89:33-46.

(3.) Manni JJ, Berenos-Riley LC. Ossification of the ear: A case report and review of the literature. Eur Arch Otorhinolaryngol 2005;262 (12):961-4.

(4.) Lister GD. Ossification in the elastic cartilage of the ear. Br J Surg 1969;56(5):399-400.

(5.) Yeatman JM, Varigos GA. Auricular ossification. Australas J Dermatol 1998;39(4):268-70.

(6.) Stites PC, Boyd AS, Zic J. Auricular ossificans (ectopic ossification of the auricle). J Am Acad Dermato12003;49(1): 142-4.

(7.) High WA, Larson MJ, Hoang MP. Idiopathic bilateral auricular ossificans: A case report and review of the literature. Arch Pathol Lab Med 2004;128(12):1432-4.

(8.) Sterneberg-Vos H, Winnepenninckx V, Frank J, Kelleners-Smeets NW. Ossification of the auricle. Int ] Dermatol 2007;46(Suppl 3): 42-4.

(9.) Carfrae MJ, Foyt D. Auricular ossification resulting in external auditory canal stenosis. Ear Nose Throat J 2008;87(3): 148-9.

(10.) Machado A, Lopes M, Ferreira C. Petrified auricular cartilages pointing the diagnosis of post-partum hypopituitarism in an encephalopathic patient. Eur Arch Otorhinolaryngol 2009;266(2):305-7.

(11.) Mastronikolis NS, Zampakis P, Kalogeropoulou C, et al. Bilateral ossification of the auricles: An unusual entity and review of the literature. Head Face Med 2009;5:17.

(12.) Shehab D, Elgazzar AH, Collier BD. Heterotopic ossification. J Nucl Med 2002;43(3):346-53.

(13.) Chalmers J, Gray DH, Rush J. Observations on the induction of bone in soft tissues. J Bone Joint Surg Br 1975;57(1):36-45.

(14.) Gordon DL. Calcification of auricular cartilage. Arch Intern Med 1964;113:23-7.

Ki-Hong Chang, MD; Dong-Kee Kim, MD; Ji-Hong Kim, MD; Yong-Soo Park, MD

From the Department of Otorhinolaryngology, Catholic University College of Medicine, Seoul, Republic of Korea.

Corresponding author: Ki-Hong Chang, MD, Department of Otorhinolaryngology, Catholic University College of Medicine, 62 Yeouido-dong, Yeongdeungpo-gu, Seoul 150-713, Republic of Korea.
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Author:Chang, Ki-Hong; Kim, Dong-Kee; Kim, Ji-Hong; Park, Yong-Soo
Publication:Ear, Nose and Throat Journal
Article Type:Case study
Date:Sep 1, 2011
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