Lymphoma with Focal Renal Lesion

SIGNALMENT:

Age: 9y 6m

Gender: Female Spayed

Species:Feline

Breed:DSH

Weight: 6lb

HISTORY:

The patient presented for weight loss. Abdominal palpation revealed kidney shape irregularities and concern for an abdominal mass. An abdominal ultrasound was requested to better evaluate the palpation findings and look for causes of weight loss.

ULTRASOUND FINDINGS AND IMAGES:

Kidneys - Normal size(Lt/Rt: 3.9/ 4.0cm)with a normal to mildly elongated shaped having heterogeneous hypoechoic echotexture in the cortex and medulla. There is trace/mild hypoechoic subcapsular fluid present. There is a hypoechoic, mildly vascular, rounded, well defined capsule altering nodule protruding from the cranial pole of the right kidney.(1.1x1.0cm) No pyelectasia was noted.

Image 1: Right Kidney with cranial pole capsule altering hypoechoic nodule with trace subcapsular fluid.

Bladder - The bladder is moderately distended with mildly echogenic urine with amorphous suspended debris and is of relatively normal contour and thickness. No overt obstruction, uroliths, or neoplasia noted.

Small intestine - Many to most loops of intestine are prominent and mildly to severely thickened. Duodenum 3.1-3.7mm, Jejunum 2.7-4.5mm, Ileum 6.4mm (normal wall thickness ~2.2-2.5mm, > 2.8mm abnormal Norsworthy/Estep et. al. JAVMA, Vol 243, No. 10, November 15, 2013). Many have abnormal layering with prominent disproportionate thickening of the muscularis layer.

Lymph nodes - Multiple mesenteric lymph nodes are severely enlarged with rounded shape having homogenous hypoechoic echogenicity.(~3.5x2.3cm) The ICCJ lymph nodes are mildly hypoechoic and plump. (0.7cm)

Image 2: Enlarged hypoechoic heterogenous mesenteric lymph node with hyperechoic mesentery.

Serosal Surfaces There is a trace amount of free fluid in the abdomen. Mesentery throughout the abdomen is diffusely hyperechoic.

ABDOMINAL ULTRASOUND INTERPRETATION:

Lymph nodes - the findings are severe - DDx: infiltrative neoplasia (lymphoma vs. mast cell vs. other) vs. IBD vs. infection vs. reaction vs. metastatic neoplasia

Kidneys - the findings are mild-moderate - DDX:

Chronic nonspecific change- (chronic glomerulonephritis vs. amyloidosis), chronic interstitial nephritis, chronic nephritis
Acute renal failure/Nephritis (infectious, GN, toxic, etc.) vs. Acute-on-Chronic renal failure.
Lymphosarcoma
Pyelonephritis

Right Kidney Nodule - the findings are moderate -DDx: renal lymphosarcoma - may appear as diffuse disease or focal mass, primary renal carcinoma, primary renal TCC, renal malignant histiocytosis or mastocytosis, malignant osteosarcoma, hemangiosarcoma - metastatic VS. fungal infection (Cryptococcus or Aspergillosis)

Intestines - the findings are mild-severe - DDX: inflammatory bowel disease/food intolerance vs. infiltrative neoplasia (small-cell lymphosarcoma vs. mast cell tumor) vs. parasitism (cestode) vs. dry FIP vs. fungal (histoplasmosis).

Ascites- this finding is mild - DDx: transudate vs. hemorrhagic vs. exudate

Mesentery - the findings are mild-moderate - DDx: peritonitis - inflammation vs. paraneoplastic reaction vs. infectious vs. fibrosis vs. other.

Echogenic urine - Ddx: cellular vs. lipid vs. protein vs. amorphous debris

FURTHER TESTING:

Ultrasound guided free hand biopsies of the mesenteric lymph node and the kidney nodule were collected for cytology.

CYTOLOGIC DIAGNOSIS AND FINDINGS:

Kidney Nodule: High-grade granular lymphoma

Mesenteric lymph node: High-grade granular lymphoma

The diagnosis of high-grade lymphoma is definitive (100% confidence), for both locations. The granular morphology is consistent with lymphocytes of cytotoxic T cell or possibly NK cell origin.

MICROSCOPIC DESCRIPTION:

The slides from the two locations appear very similar, are moderately to highly cellular, and consist of few red blood cells and a nucleated cell population predominated by large immature lymphocytes, with few small lymphocytes, and occasional neutrophils. The large lymphocytes consist of a small amount of basophilic cytoplasm that occasionally contain few small pink manuals, a perinuclear clear area, and a large round nucleus with a finely-stippled chromatin pattern and 1-3 prominent nucleoli. Occasional mitotic figures are noted. The background consists of many lymphoglandular bodies and occasional free nuclei.

Image 3:Kidney: Numerous large immature lymphocytes

DISCUSSION:

Lymphoma is a commonly found neoplasia of feline patients. These patients may present with vague clinical signs such as weight loss and malaise. The incidence of renal involvement in feline lymphoma patients is estimated to be 3.6% to 30%. Multicentric lymphoma is suspected in this patient due to a focal renal lesion(rather than bilateral renal enlargement) and lymph node involvement with intestinal changes suggestive of lymphoma.

OUTCOME:

The referring veterinarian and patient owner are performing additional baseline diagnostics and discussing options for treatment.

REFERENCES:

Debruyn K, Haers H, Combes A, et al. Ultrasonography of the feline kidney: Technique, anatomy and changes associated with disease. Journal of Feline Medicine and Surgery. 2012; 14 (11): 794-803. doi: 10.1177/1098612X12464461

Valdés-Martínez A, Cianciolo R, Mai W. Association between renal hypoechoic subcapsular thickening and lymphosarcoma in cats. Vet Radiol Ultrasound. 2007 Jul-Aug;48(4):357-60. doi: 10.1111/j.1740-8261.2007.00256.x. PMID: 17691636.

The Curbside guide- Diagnosis & Treatment of Common Sonographically Detected Disease: Canine & Feline; Lindquist/ Frank/ Modler Lobetti, 2015, Sonopath LLC., pp. 181

Williams AG, Hohenhaus AE, Lamb KE. Incidence and treatment of feline renal lymphoma: 27 cases. J Feline Med Surg, 2021 Oct;23 (10):936-944. doi: 10.1177/1098612X20984363. Epub 2021 Jan 19. PMID: 33464143

Jeon J, Song D, Ro W, Kim H, Lee G, Cho J, Jeong W, Kim S, Sur J, Park H. Renal Lymphoma with Mesenteric Lymphomatosis in a Cat. J Vet Clin 2020;37:208-212. https://doi.org/10.17555/jvc.2020.08.37.4.208

Thank you Hope Animal Hospital and Eastern Vet Path for collaborating with us on this case !