Skeletal muscle dissemination in a dog with T‐cell lymphoma

A 5‐year‐old spayed female American Staffordshire was referred for weakness, reluctance to move and distension of the abdomen. Three weeks before, the dog underwent surgery for excision of a nodular mass suspected to be a non‐epitheliotropic cutaneous T‐cell lymphoma (NE‐CTCL). Computed tomography revealed heterogeneous enhancing mesenteric masses and nodular lesions of soft tissue density, and infiltration of the abdominal muscular wall. Moreover, a pattern of diffuse muscle nodules in the skeletal muscles was visible, with lesions showing homogenous, heterogeneous or ring enhancement. Necrosis was histologically observed and these lesions were infiltrated by CD3‐positive and CD20‐, CD79a‐ and Iba1‐negative neoplastic lymphocytes. On the basis of the immunopathological features metastatic NE‐CTCL was suspected. Skeletal muscle metastasis has been rarely reported in small animals and this case report further confirms that this possibility should be considered in dogs with lymphoma. Skeletal muscles metastases are considered quite rare in small animals. When it occurs, muscle metastases typically involve paravertebral muscle and hind limb. Whole‐body CT is of paramount importance in patients affected by neoplasms with potential systemic metastases.