Contributed by 1Brian H. Le, MD, 2Stamatios G. Psarros, MD
1Department of Pathology, 2Department of Surgery, Division of Neurosurgery, Reading Hospital, West Reading, PA
A 60 year-old male presented with progressive lower back pain of approximately two years duration. He reported ambulatory dysfunction and paresthesia in the feet, confirmed by clinical exam. Of note is that more than 15 years prior he had undergone back surgery for a lumbar lesion; however, pathologic material from the first surgery was not available for review. An MRI was performed, showing a homogeneously enhancing lobulated mass extending from the lower L4 through the mid S1 regions. The lesion was intradural, hypointense on T1, and moderately intense on T2 (Figure1), measuring 6.0 cm in greatest extent. The patient subsequently underwent an L4-5 laminectomy for resection and debulking of this spinal tumor, which yielded an approximate 4 mL aggregate of tan-pink tissue.
At the time of intraoperative consultation, cytologic smear preparations were performed, showing aggregates and dyshesive epithelioid cells with abundant cytoplasm (Figure 2). Nuclei are monomorphic, round to oval, eccentrically located, and show a stippled chromatin pattern (Figure 3).
Permanent histologic examination of the tumor shows a cellular proliferation of epithelioid cells with a nest-like, organoid configuration. Pseudorosette-type architectural features are also observed (Figure 4). Neoplastic cells show eccentric nuclei and stippled chromatin, correlating with features seen in the cytologic preparations (Figure 5). Rare mitotic Figures are identified, and prominent blood vessels are present throughout the lesion. A reticulin preparation accentuates background vasculature, without evidence of pericellular fibrosis (Figure 6). A panel of immunohistochemical preparations is performed, with neoplastic cells showing reactivity for synaptophysin (Figure 7), chromogranin (Figure 8) and CD56. An S-100 immunostain showed scattered sustentacular cells. No reactivity for GFAP or for the EMA is observed. What is your diagnosis?