Myoepithelial carcinoma of soft tissues and bone.

Aim: Myoepithelial carcinoma occurs mainly in salivary glands but rarely can also occur in soft tissues or bone. In this paper, we evaluated the role of surgical margins, radiotherapy, and chemotherapy in myoepithelial carcinoma of soft tissue and bone (MC-SB) treated at our Institute.

Methods: Medical records of 33 patients presenting with MC-SB between 1998 and 2015 at our institution were retrospectively analysed, and diagnosis and treatment were studied.

Results: The median follow-up was 58.5 months. Twenty patients had tumours originating in soft tissues and 13 in bone. Eight patients (24.2%) had metastases at diagnosis, the remaining 25 had localised disease. Thirty-two underwent resection of the primary lesion. In 29 surgical margins were evaluated: wide in 28 with 10/28 who recurred (35.7%) and marginal resection in 1 who also recurred. Six patients received adjuvant radiotherapy. Metastases developed in 15/25 patients (60%) with localised disease at onset. Chemotherapy was administered in patients with metastatic advanced disease. Cisplatin+doxorubicin was administered in six patients as first-line chemotherapy with an objective response in 5/6 patients with a median 4-month duration. Five-year overall survival rate was 62.6% in patients with localised tumours and 12.5% in those metastatic at diagnosis.

Conclusions: MC-SB showed a high incidence of local recurrences and metastases. Despite different chemotherapy regimens, the outcome remains poor in patients with metastatic disease. Due to the absence of a standard protocol, we encourage treatment by multidisciplinary teams in referral centres with renowned expertise.