Eccrine porocarcinoma of the ear mimicking basaloid squamous cell carcinoma

Abstract

Abstract Objectives: Eccrine porocarcinoma (EP) is a rare malignant tumor arising from the eccrine sweat gland. EP of the ear is exceedingly rare; to our knowledge, only 5 cases have been reported in the American and European literature. We describe the unusual case of an EP arising in the left ear mimicking basaloid squamous cell carcinoma (SCC). Methods: A 60-year-old female patient presented with a verrucous, cauliflower-like tumor of her left ear. The patient claimed that the lesion had been present for almost 40 years. Computed tomography did not reveal any sign of bony destruction of the mastoid. Magnetic resonance imaging showed enlarged lymph nodes in the left parotid gland and the left neck. A biopsy was performed and a basaloid squamous cell carcinoma was diagnosed. Results: The patient underwent an ablation of the left ear, a subtotal left parotidectomy and a selective, ipsilateral neck dissection (levels II-IV). The final histology revealed an EP. The margins of resection were free of tumor and there were no signs of parotideal tumor infiltration or lymph node metastases. Conclusion: Extensive surgical resection represents the therapy of choice for patients with eccrine porocarcinomas. Regional lymph node metastases are found in about 20% and distant metastases in about 10% of patients. On a small biopsy the accurate distinction between EP, SCC, and basal cell carcinoma may be impossible. The case presented highlights this diagnostic histopathologic challenge. Although extremely rare, EP should be included in the differential diagnosis of skin tumors in the head and neck.