PMC6784618_01
Clinical photographs. (A, B) A mass with an old operation scar is present in the abdominal wall.
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LUQ of the abdomen (Fig. 1). Laboratory tests are non-specific.
A computed tomography scan shows and abdominal wall mass (in red circle).
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On computed tomography (CT), a 5x6-cm tumor was observed between the skin and subcutaneous tissue in the LLQ of the abdomen (Fig. 2).
Microscopic findings. The transformation from neurofibroma (left area) to malignant peripheral nerve sheath tumor (right area) is present (hematoxylin and eosin stain, x100).
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Histologic testing showed tissue with specific spindle cells that were longitudinal and wavy, transformed from neurofibroma with low cellularity to MPNST with increased cellularity and pleomorphic cells (Fig. 3).
Immunochemical findings. The tumor cells are weakly positive for S100 protein (A) and negative for H3K27me3 (B) (immunohistochemial stain, x200)
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On immunochemistry testing, an S100 protein test was weakly positive, and H3K27me3 staining was negative (Fig. 4); based on these results, we made a definite diagnosis of MPNST.