A Strange Case of Recurrent Pain and Swelling in the Upper Limbs

Author(s): Roberta Barolo, Giulia Pruccoli, Carlotta Covizzi, Nathalie Bini, Federica Mignone, Francesco Licciardi, Erika Silvestro, Silvia Garazzino

Myositis ossificans (MO) is a benign and rare condition characterized by the heterotopic non-neoplastic bone formation within skeletal muscle and/ or soft tissues. There are 3 forms of MO of which the traumatic is the most frequent, while non-traumatic MO is exceptionally rare especially in pediatric age, as evidenced by the few studies published in the literature. MO mainly affects adolescents and young adults; lesions are usually found in muscles of the lower and upper limbs. Major injury and minor repeated trauma are considered the most common etiological hypotheses. The presenting symptoms are usually pain, the presence of a soft tissue mass with tenderness over the swelling, overlying hot and erythematous skin. MO should be differentially diagnosed with other benign lesions, with malignant lesions and infections. Given the rarity of this condition, early diagnosis can be difficult to achieve but is fundamental to avoid unnecessary investigations and treatments and to reach a successful outcome. Ultrasonography, X-ray and MRI can show the characteristic pattern of calcification of MO; biopsy is not necessary if radiographic investigations allow definitive diagnosis. Therapies for MO include conservative treatment and surgical excision, the latter indicated in cases of neurovascular impairment, functional limitations, major aesthetic alteration.

We present the case of a 14-year-old girl with non-traumatic MO in the forearm presenting with long lasting pain and swelling; the clinical presentation, diagnostic process, radiological findings and management of this unique case are discussed.