Microcystic/reticular schwannoma occurring in cervical spine: report of a case with literature review

Abstract

To study the morphologic characteristics, immunophenotype and differential diagnosis of a case of microcystic/reticular schwannoma occurring in cervical spine. The pathologic features and immunophenotypic profile of a case of microcystic/reticular schwannoma were studied. Immunohistochemistry was performed using EnVision two-step method. The patient was a 35-year-old male and presented with a bump over the fifth cervical spine on radiologic check up. Grossly, the bump was gray-white in color, soft, well-circumscribed but non-encapsulated. The tumor measured 3.5 cm × 3.0 cm × 1.8 cm in size. Histologically, it was composed of two distinctive components. One component resembled the conventional schwannoma but showed focally nuclear pleomorphism, reminiscent of changes in degenerating schwannoma. The other component consisted of epithelial-like cells arranged in a reticular or lace-like pattern, amongst a myxoid matrix. Immunohistochemical study showed that the tumor cells were strongly positive for vimentin, S-100 protein, glial fibrillary acidic protein and neuron-specific enolase, focally positive for CD68, CD10 and Ki-67, and negative for pan-cytokeratin, epithelial membrane antigen, neurofilament, carcinoembryonic antigen, smooth muscle actin, estrogen receptor, progesterone receptor and p53. Microcystic/reticular schwannoma is a novel variant of schwannoma, arising mainly in internal viscera but seldom in bone. Awareness of this entity is helpful in distinction from chordoma, other mucoid tumors or sarcomas.