Calcific myonecrosis following snake bite: a case report and review of the literature

Calcific myonecrosis is a rare condition in which muscle in a limb compartment undergoes necrosis and becomes peripherally calcified with central liquefaction. The patient usually presents with a slowly progressive enlarged mass that sometimes can be misdiagnosed as soft tissue sarcoma. Most of the reported cases showed that the disease occurs often after trauma or compartment syndrome. However, the case of calcific myonecrosis following snake bite is rarely reported.

A 66-year-old Thai woman presented with a gradually progressive enlarged mass over a period of 10 years in her left leg. She had a history of untreated compartment syndrome after she was bitten by a snake (Malayan pit viper) in her left leg when she was 14-years old. At presentation, a plain X-ray showed a large soft tissue mass at the anterior compartment of her left leg. A sheet-like mass with an enlarged central cavity combined with peripheral calcification and cortical erosion of her tibia were observed. A biopsy was performed and the result was negative for neoplastic cells. During a 5-year follow-up, the mass progressively enlarged and then became infected and finally broke through the skin. She was treated by excision of the mass and administration of antibiotics. The wound completed healed at 1 month postsurgery. There was no wound complication or disease recurrence at 1 year postoperation.

The diagnosis of calcific myonecrosis was done by history taking and radiographic interpretation. In an asymptomatic patient the management should be observation and clinical follow-up. A biopsy should be avoided due to the high rate of postoperative infection. Treatment of choice in a symptomatic condition is mass excision.