Lymphoid neoplasms of the urinary tract and male genital organs are relatively rare, comprising less than 5% of all primary extranodal lymphomas; only a handful of small case series and isolated case reports have been published describing their predominant sites and subtypes. We identified 40 patients with lymphoid neoplasms of the urinary tract and male genital organs. Hematoxylin and eosin slides and immunohistochemical stains were reviewed, and follow-up data were also obtained. Twenty-six of 40 cases (65%) were primary genitourinary lymphomas. Mean age at diagnosis was 56 years (range 4-86 years). Among renal, bladder, and ureter lymphomas, a male predominance was noted (1.6:1). The subtypes of the lymphoid neoplasms observed were diffuse large B-cell lymphoma (17 cases, 43%); Burkitt lymphoma, extranodal marginal zone lymphoma, SLL/CLL, and follicular lymphoma (4 cases, or 10% each); B-cell ALL (2 cases, 5%); B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma, mantle cell lymphoma, plasmacytoma, polymorphic post-transplant lymphoproliferative disorder, and peripheral T-cell lymphoma NOS (1 case, or 2.5% each). In most cases, the genitourinary tract was the site of initial presentation. Genitourinary tract lymphomas most commonly occurred in the kidney. B-cell non-Hodgkin's lymphomas predominated, with diffuse large B-cell lymphoma being the most common subtype in the entire group. Extranodal marginal zone lymphoma was seen only in the kidney, rather than the bladder, where it is typically thought to be more common. Although this study confirms the predominance of diffuse large B-cell lymphoma in extranodal sites, the findings also highlight the variety of lymphomas that may occur in the genitourinary tract. This diversity of subtypes affirms the importance of fully characterizing lymphomas by immunohistochemistry and other modalities, which are indispensable for accurate diagnosis.

SUMMARY South American weakly electric fish produce a variety of electric organ discharge (EOD) amplitude and frequency modulations including chirps or rapid increases in EOD frequency that function as agonistic and courtship and mating displays. In Apteronotus leptorhynchus, chirps are readily evoked by the presence of the EOD of a conspecific or a sinusoidal signal designed to mimic another EOD, and we found that the frequency difference between the discharge of a given animal and that of an EOD mimic is important in determining which of two categories of chirp an animal will produce. Type-I chirps (EOD frequency increases averaging 650Hz and lasting approximately 25ms) are preferentially produced by males in response to EOD mimics with a frequency of 50–200Hz higher or lower than that of their own. The EOD frequency of Apteronotus leptorhynchus is sexually dimorphic: female EODs range from 600 to 800Hz and male EODs range from 800 to 1000Hz. Hence, EOD frequency differences effective in evoking type-I chirps are most likely to occur during male/female interactions. This result supports previous observations that type-I chirps are emitted most often during courtship and mating. Type-II chirps, which consist of shorter-duration frequency increases of approximately 100Hz, occur preferentially in response to EOD mimics that differ from the EOD of the animal by 10–15Hz. Hence these are preferentially evoked when animals of the same sex interact and, as previously suggested, probably represent agonistic displays. Females typically produced only type-II chirps. We also investigated the effects of arginine vasotocin on chirping. This peptide is known to modulate communication and other types of behavior in many species, and we found that arginine vasotocin decreased the production of type-II chirps by males and also increased the production of type-I chirps in a subset of males. The chirping of most females was not significantly affected by arginine vasotocin.

Rapid and accurate differential diagnosis between Burkitt lymphoma (BL) and CD10+ diffuse large B-cell lymphoma (DLBCL) is imperative because their treatment differs. Recent studies have characterized several antigens differentially expressed in these 2 types of lymphoma. Our goal was to determine whether use of these markers would aid in the differential diagnosis of BL vs CD10+ DLBCL by flow cytometric immunophenotyping (FCI). Twenty-three cases of CD10+ B-cell lymphomas with available cryopreserved samples were identified (13 BL and 10 CD10+ DLBCL). Multiparameter FCI was performed using the following antibodies: CD18, CD20, CD43, CD44, and CD54 and isotype controls. Expression of CD44 and CD54 was detected at a significantly lower level in BL compared with CD10+ DLBCL (P = .001 and P = .01, respectively). There was not a significant difference in expression of CD18 and CD43. Our data show that expression of CD44 and CD54 differs significantly between BL and CD10+ DLBCL.

Red blood cell (RBC) transfusions were requested for a 60-year-old woman with hypoplastic myelodysplastic syndrome (MDS) treated with cyclosporine to reverse progressive pancytopenia. During routine forward grouping, the patient typed as group A, but with mixed-field reactivity in the anti-A column of the gel card (Left panel, red box). Reverse typing with A1 and B cells in the right-most two gel columns was consistent with blood group A. Common causes of mixed-field agglutination were excluded, including transfusion within the last 3 months and the presence of A-subgroups.To further investigate the mixed-field result, we utilized an automated fluorescence cytometric blood typing method previously described by our group 1,2 (Right panel. The density of antigen expression [PE fluorescence] increases from left to right; isotype control [iso] is purified polyclonal IgM). These studies showed that the patient's RBCs were group A, but could be separated into two distinguishable subpopulations that differed in their levels of A antigen expression (red line). Note that the population on the left (dashed arrow), with lower PE fluorescence, nonetheless does express residual A antigen as it is shifted to the right of the isotype control reaction (blue line). The population on the right (solid arrow) shows more usual levels of A antigen expression. In agreement with the typing results on the gel card, the patient's RBCs were negative for B antigen (black line). Thus, the mixed-field reaction seen on the gel card was due to the loss of A-antigen expression on a subpopulation of the patient's RBCs-a phenomenon that has been described in MDS patients. In addition to routine blood typing 1,2 , fluorescence cytometry is a powerful method for resolving complicated immunohematologic problems.

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