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Washington University Experience | NEOPLASMS - CRANIAL AND PARASPINAL NERVEs | Malignant Peripheral Nerve Sheath Tumor (MPNST) | 11F MPNST (Case 11) recurrence (leu-7) 1
Reactivity for Leu7 (CD57) stains a subset of tumor cells, randomly distributed. ---- Not shown: The recurrent neoplasm shows strong diffuse reactivity within tumor cells for S100 protein and vimentin. Reactivity for collagen IV is strong and patchy, appearing circumferentially around individual and small groups of tumor cells, as well as blood vessels. Reactivity for neurofilament reveals few if any entrapped axons within the tumor parenchyma, consistent with a solid growth pattern. Brain parenchyma and reactive tissue adherent to the tumor show robust neurofilament staining. ---- Comment: This histological/immunohistochemical pattern is consistent with high grade malignant peripheral nerve sheath tumor with epithelioid, spindled, and papillary features. As part of this evaluation, slides from the patient's prior resection specimen were reviewed; the two specimens show consistent morphological and immunohistochemical patterns, but the epithelioid pattern predominates in the current specimen, and a new papillary pattern has emerged. Although the two resections involve separate anatomical sites, we append the current diagnosis with the phrase 'residual/recurrent' to reflect the common diagnosis and the likelihood that both tumors represent the same neoplasm.
