Anti-pan Cytokeratin monoclonal antibody, clone REM-38

A case of a patient with type 2 papillary renal cell carcinoma with eosinophilic cytoplasmatic inclusions is presented. About 50% of tumor cells were characterized by a well-circumscribed intra-cytoplasmatic round-to-oval or irregular inclusion/globule. Inclusions were 7-30 micron in diameter. They were glassy and pale to slightly eosinophilic in color in hematoxylin and eosin, were stained red by trichrome and were negative for periodic acid-Schiff reaction. Immunohistochemically, globules were negative for PAX8, epithelial membrane antigen, Carbonic Anhydrase IX, pan-cytokeratin (AE1/AE3), CD10, S100 protein, a-smooth-muscle actin, cytokeratin 7 and cytokeratin 34 beta E12. Glassy hyaline globules were not detected in any adjacent normal kidney cells. The presence of eosinophilic cytoplasmic inclusions in renal cell carcinoma, especially in papillary renal cell carcinoma, has been rarely emphasized in the literature. In this article, we review similar cases in the literature and discuss the nature of eosinophilic globules.

Poorly differentiated chordomas are rare musculoskeletal tumors. Case 1. A 42-year-old lady presented with quadriparesis of 2 months' duration. Radiologic imaging disclosed a soft tissue mass in her left prevertebral- and paravertebral cervical region. Case 2. A 4-year-old male child presented with neck pain and restricted head movements of 1-year duration. Radiologic imaging revealed a contrast enhancing, paraspinal soft tissue mass in his cervical region. Microscopic examination in both the cases revealed a cellular malignant tumor composed of moderate to markedly pleomorphic cells with interspersed mitotic figures, along with focal myxoid change and necrosis. By immunohistochemistry, tumor cells in both cases were diffusely positive for pan cytokeratin (AE1/AE3) and brachyury, whereas these were negative for INI1/SMARCB1. Tumor cells in the second case were also positive for glypican3. The first case developed pulmonary metastasis, while the second case developed recurrence. Poorly differentiated chordomas are uncommon tumors, invariably characterized by loss of INI1. These tumors can be rarely seen in adults and need to be differentiated from their diagnostic mimics, in view of treatment implications and their relatively aggressive clinical outcomes.