There are few reports since 2005 that published the myositis complication of docetaxel. We presented a case report of necrotizing fasciitis as a continuing myositis condition after docetaxel treatment.
44 years old female diagnosed with stage IIIB ductal invasive breast carcinoma, she has undergone chemotherapy with docetaxel and doxorubicin following the surgical treatment. After the 6th cycle, she had pain at both thighs, especially on the left side. It progressed until blisters and ulcers developed. Physical examination showed normal vital signs, ulceration of posterior left thigh, stiff and tender on palpation. Laboratory results showed elevated CRP and ESR, no WBC elevation or shifting of the differential count. Doppler ultrasound showed soft tissue edema with no sign of DVT or thrombus. Contrast MRI showed edema and thickening of thigh muscles. PET-CT showed a necrotic irregular pattern on subcutaneous tissue including muscles at both posterior thigh compartment with left domination. It was different from the previous PET-CT study conducted before the docetaxel treatment. She was suspected with myositis complicated by secondary infection and planned to undergo a surgical debridement. At the operation, the surgeon found necrotic muscular tissue with no sign of primary infection. Pathology examination revealed necrotic tissues with gas inclusion, inflammatory cells, and necrotic vascular tissues, these findings were consistent with necrotizing fasciitis.
In the 1990s, reports of docetaxel side effects began to revealed myopathy condition with unexplained pathophysiology. Until 2015 there are fewer than 10 cases reported the myositis complication. The proposed theory are direct myotoxicity, systemic leakage of protein in the interstitial space, increased cytokine levels (primarily IL-6, IL-8, IL-10), indirect muscle damage through hypocalcemia and hyperthermia, and accumulation of acid phosphatase in muscle lysosome. Although docetaxel induced necrotizing fasciitis was an exclusion diagnosis, this rare complication must be considered to prevent the further deteriorating condition.