Heterotopic and idiopathic ossification in the left foot of a child

ARTICLE

Auteur(s) : Keiji Sugiura¹, Mariko Sugiura¹, Kazuhiro Kurita², Toshiro Okagawa³

¹Department of Environmental Dermatology and Allergology, Daiichi Clinic, Nittochi Nagoya Bld. 2F, 1-1 Sakae 2, Nakaku, Nagoya, 460-0008, Japan
²Department of Orthopedics, Aichi Aoitori Institution for Disabled, 5-89, Nakaotai, Nishiku, Nagoya, 452-0822, Japan
³Department of Rehabilitation, Aichi Aoitori Institution for Disabled, 5-89, Nakaotai, Nishiku, Nagoya, 452-0822, Japan

A 6-year-old boy with autism had developed a round shaped hard swelling (figure 1) on his left foot the age of 3 or 4. This swelling had gradually elevated and sometimes shown inflammation. Our first diagnosis was calcifying epithelioma. X-ray showed calcification on his left foot, inside his big toe (figure 1), possibly due to ossification or polydactyly of the left foot. We treated him with surgical removal under local anesthesia. Histopathological findings showed bone tissue formation (figure 1) and no cartilage tissue. Our final diagnosis was idiopathic and heterotopic ossification (HO).

Generally heterotopic ossification (HO) is present after surgical treatment [1, 2] or trauma [3, 4]. His parents said this patient had not had any surgical operations or traumas. Therefore the origin of this ossification was unknown. Because this patient had autism, he may not have been able to express the presence of any traumas very well. We do not know when his HO developed; it was possibly present --in his left foot as early as infancy. Generally, in many polydactyly cases, bone formations are like ramifications. X-ray findings showed this case to be similar to polydactyly, because it resembles the bones in an infant stage, especially like the epiphyseal line. There were no continuances to other bones and there were no arteries and veins for this HO. Three disorders are common as ossification: Fibrodysplasia ossifications progressiva (FOP), Albright hereditary osteodystrophy (AHO) and Progressive osseous heteroplasia (POH). We discuss these disorders in table 1, which is useful for differential diagnosis. Generally, patients with autism do not have any ossification, and this patient did not have any disease and syndrome except for autism. This patient had an isolated ossification. Our final diagnosis was heterotopic idiopathic ossification in the left foot. Radiotherapy is effective for HO [5, 6]. Because this patient was 6 years old, we did not use radiotherapy due to consideration of side effects. Our treatment was a surgical operation under local anesthesia for diagnosis, there were no findings of recurrence and development after 5 months. This case was uncommon based on the origin of the HO, the clinical findings, and the age of patient.
Table 1 Differential diagnosis for ossification disease

Acknowledgements

References

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