Are you looking at lymphoma or perhaps listening to it? The diagnosis of lymphoma can be challenging, reflecting the often-insidious effects of either the primary mass or secondary spread. The case report in this issue by Talbot et al. (2025) describes an unusual location for a primary lymphoma tumour, in the interventricular septum extending around the aortic valve. Significant cardiac findings were noted on auscultation; qualities of cardiac murmurs were consistent with findings attributable to an uncommonly encountered differential diagnosis of effective aortic stenosis. Though presumably not acute in onset at this location, clinical presentation was only prompted when overt signs of periocular swelling were observed by the owner. Lymphoma accounts for 1.3 to 2.8% of equine neoplasms (Taintor and Schleis 2011) and T-cell rich, large B-cell lymphoma (TCRBCL) is the most common subtype (40-45% of cases) (Durham et al. 2012, Valli et al. 2016). Lymphoma associated with peri-ocular swelling (Murphy et al. 1989, Rendle et al. 2012) has also been reported, in this case the peri-ocular swelling was an early sentinel, preceding detection of the primary cardiac infiltration. The accompanying case report also highlights pertinent nuances when interpreting cardiac findings and provides an important aide-mémoire for presentations and manifestations of TCRBCL.