Malignant Melanocytic Schwannoma of the Nasopharynx

Malignant melanoma can metastasize widely and vary significantly in its histological appearance; it rarely presents as a deep-seated mass without an obvious primary site elsewhere. Malignant peripheral nerve sheath tumor (MPNST) is a high-grade sarcoma characterized by conventional and epithelioid subtypes. MPNST can demonstrate heterologous differentiation, usually in the form of osteosarcomatous, chondrosarcomatous, or rhabdomyosarcomatous differentiation. MPNST does not harbor true melanocytic differentiation, although epithelioid MPNST typically is diffusely S-100 protein positive and superficially can resemble malignant melanoma. An unusual intra-abdominal mass was recently encountered with features of both melanoma and conventional or epithelioid MPNST containing a fascicular spindle cell component, an epithelioid component with melanocytic differentiation, as well as a rhabdomyosarcomatous component. The terminology “malignant neuroectodermal tumor with melanocytic and rhabdomyoblastic differentiation” is proposed to describe this neoplasm, reflecting the unusual concomittant lines of differentiation as well as offering a possible rationale for nosologically challenging aspects of this neoplasm.

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“…There are rare cases, however, of MPNST that have been noted to demonstrate melanocytic differentiation. 10 – 15 …”

Section: Discussionmentioning

confidence: 99%

Malignant neuroectodermal tumor with melanocytic and rhabdomyoblastic differentiation

Tanas

Rubin

2009

Rare Tumors

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Primary melanocytic schwannoma of cervical sympathetic chain

et al. 2000

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Background Primary melanocytic schwannoma arising from the cervical sympathetic chain is a rare pigmented nerve sheath tumor. Two cases are presented from an academic medical center. Patients and Methods Patients were initially seen with an enlarging neck mass associated with sympathetic nervous system dysfunction. Radiography demonstrated a mass located posterior to the carotid sheath. Primary therapy consisted of surgical excision and postoperative radiation therapy. Results The tumors were found to be melanocytic schwannomas arising from the cervical sympathetic chain. The pathologic characteristics of this neoplasm are reviewed. One patient remained disease free for 12 years after treatment, whereas 1 patient died as a result of local recurrence and distant metastases. Conclusions Melanocytic schwannoma of the cervical sympathetic chain is a rare nerve sheath tumor of the head and neck that may be misdiagnosed as malignant melanoma. The clinical behavior of this neoplasm is variable. Preoperative neurologic findings, anatomic location, electron microscopy, and immunohistochemistry findings help to establish the diagnosis, and electron microscopy may have a role in distinguishing between benign and malignant lesions. Complete surgical excision is the treatment of choice. © 2000 John Wiley & Sons, Inc. Head Neck 22: 195–199, 2000.

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Malignant nerve sheath tumors of the head and neck: four case studies and review of the literature

Hujala

Martikainen

Minn

et al. 1993

Eur Arch Otorhinolaryngol

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Malignant peripheral nerve sheath tumors (MPNST) are very uncommon neoplasms. While the incidence of these lesions is estimated to be 0.001% in a general population, they make up 5-15% of all soft tissue sarcomas in the head and neck region. We present four cases of MPNST in the head and neck. Since certain difficulties were encountered in diagnosis, the importance of clinical evaluation is emphasized. The prognosis for these tumor patients is poor in spite of improvements in diagnostic and therapeutic modalities.

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Malignant Melanocytic Schwannoma of the Nasopharynx

Cited by 5 publications

References 8 publications

Malignant neuroectodermal tumor with melanocytic and rhabdomyoblastic differentiation

Malignant neuroectodermal tumor with melanocytic and rhabdomyoblastic differentiation

Primary melanocytic schwannoma of cervical sympathetic chain

Malignant nerve sheath tumors of the head and neck: four case studies and review of the literature

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