Primary multifocal muscular T‐cell lymphoma with cutaneous involvement in a dog: A case report and review of the literature

Abstract

Canine lymphoma represents a heterogeneous group of lymphoid neoplasms, with multicentric nodal lymphoma being the most common presentation. Musculoskeletal involvement is uncommon, and primary muscular lymphoma is a very rare presentation. Only a few cases have been described in dogs, which were of variable classification and immunophenotype. Here, we report the case of a 5-year-old female neutered Beagle that presented with an intramuscular mass on the right shoulder and associated lameness and lethargy. One month after initial presentation, multiple cutaneous nodules appeared on the head, and staging with advanced imaging revealed additional masses affecting other muscles. Cytology, histopathology, immunohistochemistry, and PCR for antigen receptor rearrangements of one of the muscle masses and skin lesions supported a diagnosis of peripheral T-cell lymphoma with large granular lymphocytes at both sites. The dog was euthanized after diagnosis due to the poor prognosis. This is the first report of primary muscular peripheral T-cell lymphoma with large granular lymphocytes and cutaneous involvement in the dog.Despite being a rare presentation, lymphoma must be considered a differential in dogs presenting with a discrete, intramuscular, soft tissue mass.

Large granular lymphocyte lymphoma in 65 dogs (2005–2023)

“…Similar to previous case reports or series, this study confirms the prognosis for canine LGLL is poor with a median OST of 28 days for dogs treated with MTDC. [12][13][14][15][16][17][18][19][20][21][22][23][24] This is similar to dogs with other aggressive forms of lymphoma such as renal lymphoma, and shorter than those with CNS or alimentary lymphoma. [29][30][31] There were numerical, but not statistically significant, differences in median OST between dogs treated with corticosteroids and chemotherapy, and those that to MTDC and those that didn't, although these may reach significance in a larger cohort.…”

“…35 Most dogs (32.8%) in this study had primary hepatosplenic LGLL, similar to previous literature where 60.9% of reported cases are hepatosplenic in origin. [12][13][14][15][16][17][18][19][20][21][22][23][24] Similar to humans, hepatosplenic lymphoma in dogs is thought to arise from cytotoxic γδ T-cells within the splenic red pulp, characterised by a CD11d + immunophenotype, although assessment for γδ or CD11d expression was not performed in any of the cases of hepatosplenic LGLL in the present study. 15 Primary gastrointestinal…”

“…This is similar to the previously reported LGLL cases where 34.8% of dogs had PB or BM involvement, although in both our study and previously reported cases not all patients underwent full staging so the true incidence of PB or BM involvement could be higher. [12][13][14][15][16][17][18][19][20][21][22][23][24] Dogs with PB involvement had shorter PFI and OST on multivariable analysis.…”

“…10,11 Canine LGL lymphoma (LGLL) is rarely described; across 13 cited publications, 23 cases of LGLL are reported. [12][13][14][15][16][17][18][19][20][21][22][23][24] Of these, hepatosplenic origin was most common, affecting 14 dogs, and most likely arising from CD11d + TCRγδ-restricted LGLs of the splenic red pulp. [13][14][15]19 Other primary sites described include peripheral lymph nodes, skeletal muscle, mediastinum, skin, urinary bladder, small intestine, spinal cord, eye, pericardium, kidney, and spleen.…”

“…Nevertheless, canine LGLL seems an aggressive form of lymphoma with only 1 dog surviving more than 195 days with chemotherapy treatment. [12][13][14][15][16][17][18][19][20][21] Due to the rare nature of this lymphoma subtype, the primary aim of this study was to assess the largest cohort of canine LGLL cases to date to better characterise clinical presentation, cytologic features, biologic behaviour and outcomes. A secondary aim was to assess clinicopathologic data for relevant prognostic factors.…”