Abstract. The canine extramedullary plasmacytoma (cEMP) has recently been the subject of numerous investigations, indicating that the histomorphologic diagnosis is often difficult because of the variety of morphologic features. Therefore, the objective of this study was to establish a subclassification scheme for cEMPs and to evaluate correlations between the types and malignancy. Retrospectively, 117 cEMPs, all immunohistochemically characterized by a monoclonal immunoglobulin light-chain expression, were collected and assigned to morphologic types. These types were compared using data from a follow-up study on metastasis and tumor recurrence, then compared by proliferation rate, determined by immunohistochemical detection of the antigen Ki-67. Histopathologic typing revealed five different types of cEMPs, ranging from the mature type with typical plasma cells to the polymorphous-blastic type. Between these two forms, three additional types were established: hyaline, cleaved, and asynchronous. Most of the cEMPs were of the cleaved and asynchronous types. In all cEMPs, mononuclear and multinuclear giant cells were present to varying degrees. Although the results of cell proliferation and the follow-up study indicated less benign behavior by the polymorphous-blastic type, the proliferation rate revealed no statistically significant differences among the cEMP types. The clinical data therefore confirmed previous findings that the risk of tumor recurrence and metastasis in general can be classed as low. The established cEMP typing system is probably a very helpful diagnostic tool, although the types cannot be used for a tumor grading system.

Summary Six canine, one feline and one equine granular cell tumours (GCTs) were investigated electron microscopically and immunohistochemically. The tumours were tested for reactivity with monoclonal antibodies against vimentin and desmin and with polyclonal antibodies against cytokeratin, S‐100 protein, glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE). All GCTs were characterized by their PAS positive cytoplasmic granules in light microscopy, which in electron microscopy appeared as lysosome‐like granules. In each case two canine GCTs were stained by the antibody against cytokeratin, vimentin and S‐100 protein. Cells of the equine GCT showed reactivity with the antiserum against S‐100 protein. In the feline GCT no reactivity with any of the antibodies tested was observed. These differences of the immunohistochemical reactions of GCTs suggest a nonuniform histogenesis of GCTs in domestic animals. The reactivity of the tumour cells with the antiserum against NSE is discussed.

Primary (extranodal) malignant lymphoma limited exclusively to the urinary bladder is an extremely rare disorder in both humans and animals and has to be differentiated from malignant lymphoma cases where a systemic (multicentric) lymphoma has spread to the bladder. We report a case of a 3-year old female spayed mixed breed dog presenting with gross haematuria and dysuria and diagnosed with a primary B-cell high-grade lymphoma of the urinary bladder without involvement of any other site. After treatment with a combination of hypofractionated external beam radiation and cytotoxic chemotherapy, rapid and complete remission of the tumor occurred. At present the dog is alive and has been in remission for 52 months.

per cent of the total floor area, at stocking densities of 130, 160 and 190 kg/m2, respectively. In practice, an estimation of the free floor area as a percentage of the total floor area in a lorry pen can be achieved by counting the number of free side panels in the pen, after the animals have been folded together. The lorry body is usually constructed in 2 ft wide panels and most lorry pens are l0 ft long, so that 40, 30, 20 and 10 per cent of total floor area, equates to two, one-and-a-half, one, and one half, free side panels, respectively. Table 2 summarises results for unshorn ewes and lambs, on folding. The folding method was considered a consistent (to within 5 per cent) way of establishing the free floor area as a percentage of total floor area for a given stocking density and for both classes of sheep. However, differentiation of the 160 and 190 kg/M2 densities in unshorn ewes was difficult. Practical adoption of this method for road, and dockside inspections would be difficult, since there is often no suitable access to lorry pens on fully laden commercial vehicles. The folding method described here, however, could be used by the livestock haulier, or inspectors, for accurate estimation of sheep stocking density at the time of loading. References CARLYLE, W. W. H., GUISE, H. J. & HENMAN, C. M. (1997) A National Survey of Transport Conditions for Sheep and Lambs. Report to Sponsors. Milton Keynes, Meat & Livestock Commission MAFF (1997) Transport of Farm Animals in Vehicles (Cattle, Sheep, Pigs, and Goats). Guidance Notes to Welfare of Animals (Transport) Order 1997. London, Ministry of Agriculture, Fisheries and Food