Brain Pathology Case of the Month - May 2011

Contributed by Wen-Xia Jiang1, Shao-Qiang Zheng2, Pei-Jun Wang2
    1Department of Pathology, Tongji University School of Medicine, Shanghai, 200092, China
    2Department of Radiology, Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China


A 37-year-old woman presented with the eye sight declined repeatedly for eight months and became more and more serious. On clinical examination, she had developed blurred vision but no focal neurological signs. Laboratory analysis showed the following: red blood cell (RBC) count, 2.591012/L; hemoglobin, 88.0 g/L; mean corpuscular volume (MCV), 106.3 fl; mean corpuscular hemoglobin (MCH), 35.0 pg; mean corpuscular hemoglobin concentration (MCHC), 330.0g/L; red blood cell distribution width (RDW), 29.0%; white blood cell (WBC) count, 15.9109/L; 55% orthochromatic erythroblasts; platelet count, 92.0109/L.

Cranial MR imaging showed multiple intracranial tumor-like masses in bilateral frontotemporal area and the top of falx cerebri. The masses were of intermediate signal intensity on Tl-weighted (Figure 1) and low signal intensity on T2-weighted images (Figure 2), and showed homogeneous enhancement after IV injection of gadolinium (Figures 3, 4), but no perilesional edema. A meningeal tail sign could be found (Figure 3). In addition, the clivus showed uniformly low signal intensity on T1- and T2-weighted images with inhomogeneous enhancement (Figures 5, 6). Differential diagnosis included, lymphoma, myeloma, leukemia and neuroblastoma and other metastatic malignant diseases,. epidural hematoma, abscess, granulomatous diseases like tuberculosis and sarcoidosis, and pachymeningeal thickening related to rheumatoid disease. After a transfusion of blood and platelets, the patient underwent craniotomy for biopsy of the left lesion. Pathological diagnosis was done (see below). The patient subsequently received whole-brain irradiation (3 Gy) in 8 fractions, which resulted in marked symptomatic improvement.

During operation, the tumor resection yielded dark red and tan tissue, measuring in aggregate approximately cm. No abnormal lesion was found in the brain parenchyma, after removing the mass from arachnoid and dura. On frozen section, diffuse foci of atypical cells and multinucleated megakaryocytes were found in inflammatory tissue. Following standard formalin fixation and paraffin processing, hematoxylin and eosin-stained histologic sections were prepared. Microscopic examination showed collections of large immature cells with moderately basophilic cytoplasm, irregular or semi-translucent nuclei with heavily stained nuclear membranes, and dark, compact chromatin particles resembling immature reticuloendothelial cells, either lying close to the clustered smaller rounded or oval cells with hyperchromatic nuclei intermingled with them (Figures 7, 8). There were scattered multinucleated cells with abundant eosinophilic cytoplasm and big irregular or lobulated nuclei with rough chromatin or nucleoli (Figures 9, 10). Immunohistochemical stains were positive for glycophorin A (Figure 11), myeloperoxidase (Figures 12, 13) and CD61 (Figure 14), respectively. A stain for leukocyte common antigen also revealed a few lymphocytes. These polymorphic cells were immunonegative for glial fibrillary acidic protein, pancytokeratin, vimentin and smooth muscle antibody. What is the diagnosis? FINAL DIAGNOSIS

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