Calcinosis of the Gastrocnemius Muscle in Juvenile Dermatomyositis: A Case Report of Successful Surgical Treatment

Summary:

Juvenile dermatomyositis is a rare pediatric inflammatory myopathy characterized by proximal muscle weakness and typical skin lesions. Although most patients achieve remission, up to 40% develop calcinosis, which may cause significant long-term morbidity. Management remains challenging, and surgical intervention is generally discouraged due to the risk of recurrence, ectopic ossification, and functional impairment. This case describes a 45-year-old man with a history of juvenile dermatomyositis in long-term remission who developed a spontaneous, painless swelling of the right calf. Imaging revealed extensive calcifications and soft tissue edema within the gastrocnemius muscle, initially interpreted as a hematoma in calcified tissue. After 2 months, the lesion became infected. Despite multiple debridements, antibiotics, and negative pressure wound therapy, the infection progressed and ultimately resulted in right-sided infective endocarditis. Magnetic resonance imaging demonstrated that calcinosis was confined to the medial gastrocnemius. Given persistent infection and failure of conservative treatment, a multidisciplinary team performed complete surgical excision of the medial gastrocnemius and its calcified extension into the Achilles tendon. Postoperative recovery was uncomplicated, and the patient regained full function. At 1 year, imaging showed no recurrence of calcinosis and full integrity of the Achilles tendon. This Case Report demonstrates that, in selected cases, when calcinosis is confined to a single muscle, complete surgical excision can provide a definitive cure, restore function, and prevent recurrence.

Juvenile dermatomyositis (JDM) is a rare inflammatory myopathy affecting 2 to 4 million children per year.^1,2 It occurs mostly in children aged 4 to 10 years and patients present with proximal muscle weakness and typical skin rashes. JDM is treated with immunosuppressive medication. Although most patients reach remission within 2 years, about 40% develop calcinosis, leading to lifelong morbidity.¹ Deposits of calcium occur in muscles, tendons, ligaments, joint capsules, and skin, with the large limb muscles most frequently affected.³ Current treatments—such as bisphosphonates, biologics, calcium-channel blockers, intravenous immunoglobulins, steroids, or surgical excision—lack consensus, and surgery is discouraged due to risks of recurrence, ectopic ossification, and functional impairment.^2,4,5 In this Case Report, we describe a patient with late sequelae of generalized calcinosis and, in particular, an infected calcinosis of the gastrocnemius muscle due to JDM.

CASE DESCRIPTION

A 45-year-old man with a history of JDM presented with a spontaneous, painless swelling of the right calf. He was first diagnosed with JDM at the age of 9 years and had been treated at various times with high doses of prednisolone. He was diagnosed with ectopic bone formations in his lower legs and in the muscles of the thorax and upper extremities. The JDM was in drug-free remission since adolescence, with no progression for 27 years.

In 2023, the patient developed a rigid swelling of 10 cm by 10 cm in the posterior upper third of the right lower leg. An x-ray demonstrated calcifications and soft tissue edema in the superficial posterior compartment of the lower leg (Fig. 1). Given his history, the swelling was diagnosed as a spontaneous hematoma within calcified muscle. No further investigations were performed to rule out, for example, malignant sarcomas. Initially, conservative treatment was chosen as the swelling was painless and nonprogressive.

Fig. 1.

Radiograph demonstrating excessive calcinosis of the gastrocnemius muscle.

After 2 months, the patient presented with an ulcerous wound in the center of the swelling and a fever. The patient was referred to the surgery department, where surgical excision of the infected wound (culture revealed Staphylococcus aureus and group G streptococci) and excision/drainage of the hematoma was performed under general anesthesia. Excision of ectopic bone was not performed. The postoperative wound was treated with negative pressure wound therapy and antibiotics. In the following year, the patient underwent several more surgical debridements due to recurrent infection. Despite treatment, the patient developed a right-sided infective endocarditis (S. aureus, Proteus vulgaris, and Streptococcus agalactiae). A multidisciplinary meeting concluded that definitive management required surgical excision of the affected muscle. Magnetic resonance imaging demonstrated extensive calcifications of the medial head of the gastrocnemius muscle, whereas the lateral head and the soleus muscle were unaffected (Fig. 2). During surgery, the wound was excised, and a long vertical incision was made to expose the entire gastrocnemius muscle, which was calcified over its full length (Fig. 3). Subsequently, the skin was lifted from the gastrocnemius muscle, and the popliteal artery was safely dissected and protected adjacent to the gastrocnemius muscle. The medial head of the gastrocnemius muscle was completely removed, whereas the lateral head was left in place. The calcifications continued into the Achilles tendon, which was affected by approximately 50%, and this affected part of the tendon, which was the extension of the medial head of the gastrocnemius, was removed. The soleus muscle and its tendinous insertion into the Achilles tendon were left intact. During the procedure, the tibial nerve, the peroneal nerve, and the posterior tibial artery remained intact. The wound was closed primarily over 2 suction drains, followed by 2 weeks of immobilization. After 2 weeks, there was no infection or no wound dehiscence, and the drains were removed. The x-ray demonstrated a successful removal of the calcified gastrocnemius muscle. The patient was treated with a cast for 4 more weeks followed by physical therapy. Six months postoperatively, the patient was able to walk without problems, and the endocarditis had been cleared. After 1 year, the patient had regained full strength of the Achilles tendon, with ultrasound showing a 5–mm-thick tendon and radiographs confirming no recurrence of calcinosis (Fig. 4).

Fig. 2.

Magnetic resonance imaging of the right lower leg demonstrating calcinosis in the gastrocnemius muscle while demonstrating no calcinosis in the soleus muscle.

Fig. 3.

Intraoperative photograph of the calcified gastrocnemius muscle.

Fig. 4.

Postoperative radiograph.

DISCUSSION AND CONCLUSIONS

This Case Report highlights successful surgical management of extensive, infected calcinosis in JDM. Surgical excision of calcinosis is rarely performed and generally avoided due to concerns of recurrence, muscle damage, and impaired function. However, in cases of uncontrolled infection and failure of conservative treatments, surgery may be the only curative option.

Calcinosis due to JDM is a rare disease and has not been studied widely. Nonsurgical management is the current gold standard for treating calcinosis. Surgical excision may result in progression of ectopic bone formation in the affected muscle and damage to nerves and blood vessels, resulting in loss of function.^2,6 In the current case, conservative treatment included regular follow-up appointments, antibiotics, and negative pressure wound therapy. Unfortunately, these efforts yielded no sustainable wound healing. Inadequate wound healing can have several causes, such as diabetes, obesity, tobacco abuse, malnutrition, and stress.⁷ None of these were present. Computed tomography angiography demonstrated 3 patent crural arteries, ruling out vascular causes. Most likely, extensive infected ossifications resulted in inadequate clearance of bacteria despite intravenous antibiotics.⁸ We hypothesized that hibernating bacteria within the biofilm surrounding the calcinosis were the cause of recurrent infection, impaired wound healing, and ultimately endocarditis, posing a major therapeutic challenge.

Magnetic resonance imaging showed that calcinosis was confined to the medial gastrocnemius. Complete excision, which follows clear anatomical boundaries, was therefore considered the most favorable option. Surgery proceeded without complications, and recovery was optimal. Although loss of the gastrocnemius and part of the Achilles tendon raised concerns about impaired plantar flexion or tendon rupture, the patient fully regained strength and function.

Infected calcinosis is a rare but severe late complication of JDM. Conservative treatment with antibiotics, wound care, and debridement may fail when infection is sustained by extensive calcified tissue. This Case Report demonstrates that in selected cases, when calcinosis is confined to a single muscle, complete surgical excision can provide a definitive cure, restore function, and prevent recurrence.

DISCLOSURE

The authors have no financial interest to declare in relation to the content of this article.

ACKNOWLEDGMENT

The authors thank the patient for providing informed consent and for permitting the publication of this Case Report.