Fibrodysplasia ossificans progressiva

Petrification of the auricle results in a rigid and immalleable ear. The etiology of such a finding is usually ectopic calcification. The condition has been associated with injurious processes, such as cold injury, and with various endocrinopathies, including Addison disease. In a significant number of cases, ossification occurs without knowledge of the precipitating cause or event. True auricular ossification is a rare occurrence, with only 12 histologically confirmed cases in the literature. We herein present the clinical and pathologic findings of another case. A 60-year-old man with diet-controlled diabetes presented with a 10-year history of slowly and insidiously stiffened auricles. He denied any precipitating historical events. Routine testing did not demonstrate systemic abnormalities. Radiographic examination revealed opacities consistent with bony structure in the auricles of the ears, with the right more prominent than the left. Histologic sampling demonstrated ossification with deposition of trabecular bone in proximity to normal elastic cartilage.

(Arch Pathol Lab Med. 2004;128:1432-1434)

Petrification of the auricle, resulting in a rigid ear, is an uncommon occurrence. When observed, the etiology of such a finding is usually ectopic calcification.1 True auricular ossification, in which the normal cartilaginous structures of the ear are replaced by bone, is decidedly rare, with only 12 histologically confirmed cases in the literature (Table).1-11 Injurious processes, such as frostbite,1,2,6 physical trauma,3 and inflammatory conditions,8,10 are known to precipitate such an event. The condition has also been associated with various endocrinopathies.3,12-15 However, in a significant number of cases, ossification occurs without knowledge of the precipitating cause or event.10,12

REPORT OF A CASE

A 60-year-old white man presented to our clinic for routine, age-appropriate skin cancer screening. Although he had a history of actinic keratoses and had recently been diagnosed with a single nonmelanoma skin cancer, he was without specific skin complaints. During the course of his complete skin examination, it was discovered that his right ear auricle was rigid and immalleable in its entirety except for the lobule but was otherwise without appreciable cutaneous abnormalities (Figure, A). The left ear demonstrated similar textural features, but to a lesser degree. The remainder of the cutaneous and systemic examination was unremarkable.

Upon detailed questioning, the patient could not recall any history of injury to the left ear; specifically, he denied frostbite, boxing, wrestling, or any other type of physical trauma. When queried further, the patient noted that his ears had gradually stiffened during the previous 10 years, but this was entirely asymptomatic, and he had been unconcerned with this occurrence. Indeed, he appeared slightly bemused by the examining physicians' interest. His medical history was significant only for mild hypertension, hypercholesterolemia, and diet-controlled diabetes mellitus. He had not noted fatigue, weight loss, or other systemic symptoms and felt otherwise well.

Laboratory evaluation including complete blood count, basic electrolytes, serum calcium and phosphorus levels, basic liver enzymes, and thyroid function tests returned results within normal limits. Radiographs demonstrated opacities consistent with ossification and true bone formation in both auricular cartilages, but such findings were more prominent in the right ear (Figure, C). Histologic sections of the biopsy of the patient's right auricle demonstrated spicules of lamellar bone with cement lines and osteocytes, stromal component of adipose tissue, and fragments of elastic cartilage and woven bone (Figure, B and D). Osteoblastic activity was not prominent.

COMMENT

Cutaneous ossification is classified as primary when it arises de novo and secondary if it occurs within a preexisting lesion. Rare syndromic causes of primary ectopic ossification include congenital plaquelike osteomatosis, Albright hereditary osteodystrophy, fibrodysplasia ossificans progressiva, and osseous heteroplasia.11 secondary ossification, such as that following traumatic, inflammatory, or neoplastic events, is not uncommon and can be seen in a variety of lesions including acne scarring, pilomatricoma, benign melanocytic nevi, or chondroid syringoma (mixed tumor). Collagen vascular disease, such as morphea, scleroderma, and childhood dermatomyositis, may demonstrate areas of cutaneous calcification and even ectopic ossification.

Petrification of the auricle, whether by calcification, ossification, or otherwise, is an uncommon condition. Ectopic ossification represents an unusual cause of a petrified ear.1 It occurs through deposition of calcium and phosphorus in a proteinaceous matrix as hydroxyapatite crystals, and by definition it occurs in soft tissue, which does not normally ossify.6 Radiographically, it demonstrates the same opacity as normal bone, and it is histologically similar to lamellar bone found elsewhere in the body.12 In a study of 800 presumably healthy patients, Scherrer9 found no patients with stiffness or immobility of the external ears. Similarly, in 1963 Gordon8 examined 300 patients for inflexibility or nodularity of the ears and found 11 patients (3%) with calcification of the auricular cartilage by radiographic examination. Each of these patients had diseases known to predispose to heterotopic calcification including scleroderma, acromegaly, and diabetes mellitus. A review of the medical literature revealed just 12 additional cases of histologically confirmed ectopic ossification as a cause of a petrified auricle (Table).1-11

The clinical presentation of a petrified auricle has been varied. Although most patients are asymptomatic, some may have discomfort with the application of pressure.1 Gradual stiffening of the appendage, such as that demonstrated in our case, is frequently recollected by the patient. Bilaterality was more frequent than unilateral involvement. Physical examination typically reveals a rigid auricle and spared lobule, without any visible cutaneous abnormality.

Previous authors reported that severe hypothermia was the most common cause of auricular ossificans.6 Another case has been described secondary to repeated exposure to cold temperatures without frank frostbite.2 Rapid cooling may produce thrombosis and vascular occlusion with resulting ischemia, thereby inducing proliferation of lamellar bone. Repeated trauma or manipulation has been suspected of producing auricular ossification as well.3 Addison disease has been associated with ossification of the auricular cartilage, although the mechanism is not clear.3,5 Other causes of petrified auricles include mechanical trauma,8,9,13 radiation therapy,n insect bites,9,13 and various inflammatory conditions including chondritis,9,13 perichondritis,8-10 and syphilis.8,9,13 Endocrinopathies such as hypopituitarism,14,15 diabetes mellitus,9,13-15 acromegaly,10,13 and hypothyroidism15 have also been associated with petrification of the auricle. The pathogenesis of calcification, or more rarely ossification, in these conditions has not been well established. Although our patient did suffer from mild diabetes mellitus, the high prevalence of this condition, coupled with the rarity of auricular ossification, mitigates against a strong causal association. Evidence of another endocrine abnormality was not detected in our otherwise healthy patient. Experts have suggested that laboratory investigation be guided by the patient's clinical history and physical examination, and an extensive workup is not generally warranted.1

Because of the rarity of this condition, information regarding treatment is limited. In cases of extreme discomfort, particularly that with sleeping postures, surgical intervention, including conchal reduction through a posterior incision or frank wedge resection, has been employed.4,7 Additional reporting and experience may further elucidate pathophysiologic mechanisms and treatments, respectively.

References

1. Stites PC, Boyd AS, Zic J. Auricular ossificans lectopic ossification of the auricle). J Am Acad Dermatol. 2003;49:142-144.

2. Lautenschlager S, Itin PH, Rufli T. The petrified ear. Dermatology. 1994; 189: 435-436.

3. Cohen AM, Talmi YP, Floru S, et al. X-ray microanalysis of ossified auricles in Addison's disease. Calcif Tissue Int. 1991;48:88-92.

4. Lari AA, al-Rabah N, Dashti H. Acrobatic ears: a cause of petrified auricles. Br J Plast Surg. 1989:42:719-721.

5. Cohen AM, Talmi YP, Floru S, Bar Ziv J, Zohar Y, Djaldetti M. Ossification of the auricle in Addison's disease. J Laryngol Otol. 1989;103:885-886.

6. DiBartolomeo JR. The petrified auricle: comments on ossification, calcification and exostoses of the external ear. Laryngoscope. 1985:95:566-576.

7. Lister G. Ossification in the elastic cartilage of the ear. Br J Surg. 1969;56: 399-400.

8. Gordon EJ. Diffuse inflammation of cartilage. J Bone Joint Surg. 1964:30: 944-956.

9. Scherrer F. Calcification and ossification of the external ears. Ann Otol. 1932;41:867-885.

10. Knapp H. Ossification of the auricle in consequence of perichondritis seropurulenta. Arch Otol. 1890:19:45-50.

11. Yeatman IM, Varigos GA. Auricular ossification. Australas J Dermatol. 1998;39:268-270.

12. Kewlarmani L. Ectopic ossification. Am J Phys Med. 1977;56:99-121.

13. Batson J. Calcification of the ear cartilage associated with the hypercalcemia of sarcoidosis. N Engl J Med. 1961;265:876-877.

14. Randall RE Jr, Spong FW. Calcification of the auricular cartilage in a patient with hypopituitarism. N Engl J Med. 1963;269:1135-1137.

15. Barkan A, Glantz I. Calcification of auricular cartilages in patients with hypothyroidism. J Clin Endocrinol Metab. 1982;55:354-357.

Whitney A. High, MD; Matthew J. Larson, MD; Mai P. Hoang, MD

Accepted for publication August 16, 2004

From the Department of Dermatology, Section of Dermatopathology, University of Colorado Health Sciences Center, Aurora (Dr High); the Department of Dermatology, Columbia Park Medical Croup, Minneapolis, Minn (Dr Larson); and the Department of Pathology, University of Texas Southwestern Medical Center, Dallas (Dr Hoang).

The authors have no relevant financial interest in the products or companies described in this article.

Corresponding author: Whitney A. High, MD, University of Colorado Dermatopathology Consultants, Department of Dermatology, University of Colorado Health Sciences Center, 1665 N Ursula St, Aurora, CO 80010 (e-mail: wahigh50@hotmail.com).

Reprints not available from the authors.

Copyright College of American Pathologists Dec 2004
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