J Pathol Transl Med.  2017 Sep;51(5):505-508. 10.4132/jptm.2017.01.04.

A Rare Case of Aggressive Melanotic Schwannoma Occurred in Spinal Nerve of a 59-Year-Old Male

• Choi SE
• Cha YJ
• Kim J
• Cha H
• Seo J
• Kuh SU
• Kim SJ
• Kim SH

• KMID: 2392570
• DOI: http://doi.org/10.4132/jptm.2017.01.04

Abstract

Melanotic schwannoma (MS) is a rare variant of nerve sheath neoplasm that shows ultrastructural and immunophenotypical features of Schwann cells but also has cytoplasmic melanosomes and is reactive for melanocytic markers as well. Unlike conventional schwannoma, which is totally benign, MS has an unpredictable prognosis and is thought to have low-malignant potential. Herein, we present a rare case of recurrent MS in lumbar spine of a 59-year-old male.

Keyword

Melanotic schwannoma; Spine; Recurrence; Metastasis

MeSH Terms

Cytoplasm
Humans
Male*
Melanosomes
Middle Aged*
Neoplasm Metastasis
Nerve Sheath Neoplasms
Neurilemmoma*
Prognosis
Recurrence
Schwann Cells
Spinal Nerves*
Spine

Figure

• 

  Fig. 1. Radiologic findings of spinal melanotic schwannoma. (A) Magnetic resonance imaging of lumbar spine reveals a destructive mass of the vertebral body. (B) Metastatic pulmonary nodule in left upper lobe with increased fluorodeoxyglucose uptake on positron emission tomography–computed tomography (arrowheads).

• 

  Fig. 2. Gross, microscopic and ultrastructural findings of melanotic schwannoma. (A) A heavily pigmented black round mass of vertebral body has infiltrative margin. (B) Tumor cells permeate the bone marrow space of vertebra (left). Note the right sided normal bone marrow that shows retained trabecular bone and marrow space containing hematopoietic cells. (C) Epithelioid tumor cells have discernible cytoplasmic membrane, pleomorphic nuclei, and cytoplasmic melanin pigments. Note the mitosis (center) and prominent nucleolus. (D) Foci of tumor necrosis are seen. Human melanoma black 45 (E) and S-100 protein (F) are diffusely and strongly positive in tumor cells. (G) Collagen type IV staining reveals pericellular membranous staining of tumor cells, implying the presence of basal lamina. (H) On electron microscopy, abundant basal lamina of tumor cell is evident with cytoplasmic melanosomes (×12,000) (inset, ×5,000).

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