Melanotic schwannoma of the neck mimicking a malignant melanoma

Abstract

We report a case of a 42-year-old female patient who presented with a 5-month history of a right cervical swelling. A fine-needle aspiration biopsy performed elsewhere led to the diagnosis of malignant melanoma. Clinical examination revealed pigmented skin and mucous-membrane lesions of the pharynx. Diagnostic exstirpation of the cervical tumor resulted in the intraoperative diagnosis of a malignant melanoma. Subsequent pathological examination including ultrastructural analysis allowed the revision of the diagnosis to that of melanotic schwannoma, a rare, pigmented nerve sheath tumor. Further analysis of the tissue obtained from neck dissection revealed additional melanotic schwannomas. With regard to prognostic and therapeutic issues, it is necessary to differentiate these tumors from the more common metastatic malignant melanoma. The preoperative differential diagnosis is very difficult, as light microscopy and immunocytochemistry allow no discrimination in small biopsies. Although the occurrence of multiple schwannomas points to a hereditary syndrome, our patient did not fulfill the criteria of Carney’s syndrome or other known syndromes, suggesting a so far unknown genetic background.