selleck inhibitor Neuroendocrine markers are positive. The differential includes lymphoma. Figure 15 Low grade neuroendocrine carcinoma, showing rosette-like aggregates and eccentric nuclei. No necrosis or mitoses present (DQ, 200×). Lymphoma Aspirates are cellular and consist of dispersed single cells with high nuclear/cytoplasmic ratios. Smear background

shows lymphoglandular bodies (“blue blobs”-rounded cytoplasmic fragments), these are best appreciated on Diff-Quik stains. The scant cytoplasm frequently Inhibitors,research,lifescience,medical stains intensely blue on Diff-Quik stains (Figure 16). The differential diagnosis includes small cell carcinoma and other neuroendocrine neoplasms. Flow cytometry and immunostains for various lymphoid markers (CD45) are positive for exact classification (17).

Figure 16 Lymphoma involving the liver with lymphoglandular bodies and a monotonous population of small cells with scant cytoplasm; the Inhibitors,research,lifescience,medical larger cells are reactive hepatocytes (DQ stain, 400×) Melanoma Aspirates are cellular Inhibitors,research,lifescience,medical consisting of dispersed single cells or pseudo cohesive when there is marked cellularity. Cells are usually polygonal, but may be spindle, small cell or anaplastic in morphology. Nuclei may be plasmacytoid/eccentric with single large nucleoli (Figure 17). Mirror-image binucleation is common. Melanin pigment if present will be dark blue on Diff-Qiuik stain, and yellow-brown, non refractile Inhibitors,research,lifescience,medical on Papanicolaou stain. Tumor cells are S-100, HMB-45, CD117 Melan-A positive (18). Figure 17 A. melanoma of an obvious nature, with pleomorphic multinucleated cells, plentiful brown melanin pigment present (Pap stain, 400×); B. melanoma metastatic to liver with copious melanin pigment (H&E, 200×) Metastatic melanoma is particularly challenging on liver aspiration as the tumor cells have several features in common with both normal and neoplastic hepatocytes – polygonal Inhibitors,research,lifescience,medical cells with granular cytoplasm, and intra-nuclear cytoplasmic

inclusions (Figure 18). The diagnosis may be missed if appropriate stains are not ordered in cases where the primary tumor is unknown or the information has not been relayed to the pathologist. AV-951 Ocular melanomas have a peculiar tendency to metastasize to the liver, often many years after the initial diagnosis. Therefore beware the glass-eyed patient with liver enlargement! Figure 18 Amelanotic melanoma with single cells and occasional intranuclear pseudo-inclusions mimicking poorly differentiated HCC (Pap stain, 400×) Clear cell renal cell carcinoma Tumor cells have abundant clear cytoplasm and central round nuclei. The nuclear/cytoplasmic ratios do not appear to be elevated. There is often a prominent capillary vascular network (Figure 19). Tumor cells are vimentin and CD10 positive. The differential includes clear cell variant of HCC.