Polymyositis--an unusual presentation of cGvHD in children

Chronic graft-versus-host disease presenting as acute polymyositis: A case series and systematic review

Chronic graft-versus-host disease (cGvHD) remains a significant complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Commonly targeted organs are skin, eyes, mouth, gastrointestinal tract, and liver. Muscular involvement and presentation as acute polymyositis (APM) remain a rare manifestation of cGvHD. We present a case series of three patients who presented with APM as a sole presentation of cGvHD and were treated successfully with corticosteroids and ruxolitinib. We also conducted a systematic review including 72 patients to summarize current literature regarding APM associated with cGvHD after allo-HSCT. The estimated incidence of cGvHD-associated APM is up to 3.4%, with a median time to onset of 1.6 years post-allo-HSCT. Most cases (85%) presented with myalgia and progressive bilateral proximal muscle weakness with elevated creatine kinase and/or aldolase. Over half of the patients had a prior history of acute GvHD. Isolated APM presenting without other clinical manifestations of cGvHD was rare. Biopsy of affected muscles usually shows characteristic myonecrosis, which remains the gold standard for diagnosis. Most cases respond to systemic steroids and immunosuppressive therapy. However, refractory cases remain challenging to treat and can cause significant morbidity and mortality. Ruxolitinib appears to be an effective therapy in this setting.

Polymyositis in a child with thalassemia after hematopoietic stem cell transplantation: A case report

RATIONALE

Polymyositis (PM) is a rare neuromuscular phenotype of chronic graft-versus-host disease (cGVHD). Although glucocorticoids have been shown to be effective in the treatment of PM, most people experience poor treatment response and poor prognosis.

PATIENT CONCERNS

A six-year-old boy with thalassemia received allogeneic hematopoietic stem cell transplantation (HSCT) and consequently developed sudden myasthenia of limbs 17 months after the transplant.

DIAGNOSES

Medical history, current symptoms, laboratory examinations, and imaging findings of the patient indicated cGVHD complicated with PM.

INTERVENTIONS

He was then given high-dose corticosteroid therapy, including tacrolimus, ruxolitinib, and rituximab.

OUTCOMES

Twenty-three months after transplantation, creatine kinase levels returned to normal range, and the MRI showed that the original muscle edema signal was significantly improved. The patient's muscle weakness continued to improve, and his overall condition was good.

LESSONS

This report suggests that glucocorticoids combined with immunosuppressants may be effective against polymyositis. Rituximab and ruxolitinib may be a good choice in treating polymyositis.

Chronic Graft-Versus-Host-Disease-Related Polymyositis: a 17-Months-Old Child with a Rare and Late Complication of Haematopoietic Stem Cell Transplantation

Background

Chronic graft versus host disease (cGVHD) occurs in 20–30% of paediatric patients receiving haemopoietic stem cell transplantation (HSCT). Neuromuscular disorders such as polymyositis are considered a rare and distinctive but non-diagnostic manifestation of cGVHD and, in the absence of other characteristic signs and symptoms, biopsy is highly recommended to exclude other causes.

Case report

We report a case of a 17-months-old child affected by hemophagocytic lymphohistiocytosis who underwent a matched unrelated donor haematopoietic stem cell transplantation (HSCT). She developed severe cGVHD-related polymyositis that was successfully treated with high-dose steroid therapy, rituximab and sirolimus.

Conclusions

This is the first case of cGVHD-related-polymyositis described in a pediatric patient which was successfully treated with rituximab.