Abstract

We report the case of a 9-year-old girl who presented to the emergency unit with general asthenia, myalgia, and difficulty to walk and stand evolving from 1 month. The diagnosis of myositis ossificans was ultimately made on clinical and conventional radiography finding. This case presents a rare form of myositis ossificans and highlights the contribution of the conventional radiography in the diagnosis workup of myositis ossificans.

Citation: Saber A. Unusual myositis ossificans. Open J Clin Med Images. 2021; 1(1): 1011.

Case report

A 9-year-old girl with no significant medical history, presented to the emergency unit with general asthenia, myalgia, and difficulty to walk and stand evolving from 1 month. Clinical examination showed multiple lesions of calcinosis cutis over her lower limbs and restricted movements of both hips and knees. Lower limb radiography (Panels A and B) revealed massive and extensive calcifications of soft tissue. Laboratory parameters were normal; however, erythrocyte sedimentation rate was elevated at 65 mm/hour (normal range under 20). The diagnosis of an idiopathic myositis ossificans was made. She couldn’t have a genetic investigation lacking the financial means.

The patient was prescribed glucocorticoids, in addition to analgesics, and intravenous pamidronate.

Discussion

Myositis ossificans (MO) is the heterotopic formation of nonneoplastic bone and cartilage in soft tissue [1]. It is an extremely rare condition in children, characterized by abnormal heterotopic ossification formation, involving the striated muscle and soft tissue [2]. There are two forms: MO circumscripta which is a localized form, limited to a single muscle, and a progressive form which affects all striated muscles with a special predilection for paravertebral muscles [1]. The second form is more frequent in young children, generally due to genetic or metabolic disorders [3].

Although MO is often the result of trauma, neurological injury, surgery, burns or may be idiopathic [4]. However, its pathogenesis is still unknown, and the initiation process may be imperfectly understood [5]. Conventional radiography plays a central role in the diagnosis workup of MO, it shows rapidly progressive calcifications involving striated muscles [6]. The treatment is generally conservative as many of the lesions disappear spontaneously [7]. Non-selective non-steroidal anti-inflammatory drugs like indomethacin may stop the evolutionary process of MO [8]. Surgical resection could be suggested in case of localized forms.

This case presents a rare form of MO in a young girl, and its highlights the role of the conventional radiography in the diagnosis workup of MO.

Figure 1: Lower limb radiography showing massive and extensive calcifications of soft tissue.

References

1. Yaghmai I. Myositis ossificans: diagnostic value of arteriography. American Journal of Roentgenology. 1977; 128(5): 811‑6
2. Sferopoulos NK, Kotakidou R, Petropoulos AS. Myositis ossificans in children: A review. Eur J Orthop Surg Traumatol. 2017; 27(4): 491‑502.
3. Norman A, Dorfman HD. Juxtacortical Circumscribed Myositis Ossificans: Evolution and Radiographic Features. Radiology. 1970; 96(2): 301‑6.
4. Martin DA, Senanayake S. Myositis Ossificans. N Engl J Med. 2011; 364(8): 758‑758.
5. Ackerman LV. Extra-osseous localized non-neoplastic bone and cartilage formation (so-called myositis ossificans): clinical and pathological confusion with malignant neoplasms. J Bone Joint Surg Am. 1958; 40-A(2): 279‑98.
6. Govindarajan A, Sarawagi R, Prakash ML. Myositis ossificans: the mimicker. Case Reports. 2013: bcr2013201477‑bcr2013201477.
7. Fijn R, Koorevaar RTh, Brouwers JRBJ. [No title found]. Pharmacy World and Science. 2003; 25(4): 138‑45.
8. Kir M, Ozdemir M. Myositis ossificans around shoulder following military training programme. Indian J Orthop. 2011; 45(6): 573.