Leiomyoma of the calf muscle in a child with calcification and ossification - a case report

Leiomyomas (smooth muscle tumours) arising in skeletal muscle are extremely rare in children, especially in the extremities. A 3-year-old girl presented with a slow-growing mass in the left calf which had been present since the age of 6 months. Plain radiographs revealed a well-circumscribed mass, fusiform in shape, not attached to bone. There was widespread calcification of the tumour. MRI confirmed extensive calcification and ossification in the soleus and medial head of the gastrocnemius displacing the neurovascular bundle anteriorly. A diagnosis of a sarcoma was suggested. The mass was well defined at surgical exploration, encapsulated and easily dissected from the soleus, gastrocnemius muscles and blood vessels. The tumour was gritty on cutting with a saw and histology confirmed a leiomyoma of the soleus muscle. Immunohistochemical markers for smooth muscle actin and desmin were positive. The recovery was uneventful at five-month follow-up.