External auditory canal eccrine spiradenocarcinoma: a case report and review of literature.

Background: Eccrine spiradenocarcinoma is a rare dermal appendage carcinoma believed to arise from transformation of a long-standing benign spiradenoma. This tumor demonstrates highly malignant biologic behavior with a high recurrence rate, frequent lymph node metastases, and overall poor survival.

Methods: We report the first case of eccrine spiradenocarcinoma arising in the external auditory canal. The management of this tumor, its histopathologic characteristics, and a review of literature are presented.

Results: A literature review identified 17 cases of eccrine spiradenocarcinoma in the head and neck region. Local recurrence occurred in 58.8% of patients, with an average of 23 months from diagnosis. Lymph node metastasis occurred in 35.3%, with an average of 31 months from diagnosis. Other metastatic sites included skin, bone, and lung. Disease-specific mortality was 22.2%.

Conclusions: Eccrine spiradenocarcinoma is an aggressive tumor with a poor prognosis. Primary treatment should include wide local excision with or without regional lymphadenectomy. Isolated successful treatments have been documented with adjuvant hormonal manipulation, chemotherapy, and radiation therapy.