Linfoma difuso extra nodal multicéntrico de células grandes y peque？as en un canino Reporte de caso

a 6-year old bitch was taken to the universidad de los llanos' veterinary clinic; the dog's owner did not report vaccination history or past illness. clinical examination revealed a poor physical condition (2/5), the absence of upper and lower incisors, bilateral alopecia in the nape, neck and back, wet dermatitis on the withers, hyperkeratosis, hyperpigmentation and a mild limp affecting the fore and hind limbs. euthanasia was performed, followed by necropsy; tissues were sampled, fixed in 10 % formalin buffer and sent to the animal histopathology laboratory (universidad de los llanos). the samples were processed using routine optical microscopy methods; 3-4mm thick histological sections were stained with haematoxylin and eosin (h&e), toluidine blue and periodic acid-schiff (pas) staining methods. the necropsy report sent to the animal histopathology laboratory (universidad de los llanos) reported the following macroscopic findings: a whitish, smooth to the touch, 3 x 1.5 cm mass in the urethral mucosa, and a white focus in the left renal cortex, intestinal congestion with the presence of toxocara canis and ancylostoma caninum. a large and small cell lymphoma was diagnosed in the urethra and renal cortex mucosa during histopathological analysis. microscopic examination reported dimorphic lymphoid cells having different sized eccentric nuclei, some of them binucleated. multicentric lymphoma of big and small cells located in the renal cortex and urethral mucosa was diagnosed; mastocytoma was discarded by blue toluidine method because there was no evidence of a metacromasy in the cytoplasmic granules.