Internal Medicine Case Report

Oats scottish cat

Leah Young, DVM, MS, DACVIM

Signalment: Boston, 4.5 yr, MC, DSH

HISTORY:  Boston presented to Westford Veterinary Emergency and Referral Center Internal Medicine Service for further evaluation of chronic intermittent vomiting and weight loss. His clinical signs were initially about 4-5 months earlier. Diagnostics at that time included labwork (CBC, chemistry panel, T4, Cardiopet proBNP, and urinalysis) and abdominal radiographs. The most notable finding at that time was mild eosinophilia (2,712/ul). He continued to have intermittent vomiting but was otherwise stable. A recheck CBC was performed about 6 weeks later and showed persistent and progressive eosinophilia (8,950/ul).

He started on Purina EN diet and seemed to have some improvement. About 2-3 months later he was noted to have worsening vomiting and weight loss. Reassessment at that time confirmed weight loss, but physical exam was otherwise unremarkable. Recheck labwork revealed leukocytosis (WBC 25,300/ul) characterized by lymphocytosis (7,691/ul) and eosinophilia (7,691/ul). FeLV/FIV/Heartworm test was negative. A SpecfPL was elevated (13.6). A fecal panel was performed and no parasites were seen. An abdominal ultrasound was performed and revealed a moderately sized, circumferential duodenal mass measuring 2.43×2.45×1.89cm in the proximal duodenum right after the pylorus. Walls at this location were hypoechoic and thickened (0.67cm). There was hyperechoic fat/mesentery surrounding the mass. Aboral to the mass, the duodenum was mildly thickened (0.29cm) with normal layering. The jejunum (0.19-0.22cm) and ileum (0.25cm) were normal in wall thickness and layering. The pancreas was visualized and appears mildly enlarged (0.55-0.82cm) and mildly hypoechoic. The gastric lymph node adjacent to the pylorus was hypoechoic and mildly enlarged. Boston was referred to the Internal Medicine Service at this time for further evaluation.

PHYSICAL EXAMINATION: Boston was bright, alert, and responsive on examination. He appeared hydrated and no significant abnormalities were appreciated on examination.

Diagnostics:

    • CBC: WBC 19,100/ul (elevated), MON 1,165/ul (elevated), EOS 7,907/ul (elevated)
    • Chemistry panel: no abnormalities appreciated
      fPL: 0.9 (normal)
    • Focal ultrasound of proximal duodenal lesion:

      In the very proximal duodenum, just after the pylorus, there is a moderately sized, circumferential duodenal mass measuring like ultrasound previously performed (2.5×2.55x2cm). Walls at this location are hypoechoic and thickened (0.7-0.8cm). There is hyperechoic fat/mesentery surrounding the mass with what appears to be an enlarged hypoechoic lymph node. The duodenal papilla is not definitively seen at this time. Aboral to the mass, the duodenum is mildly thickened (0.29cm) with normal layering. The rest of the small intestines appear unremarkable.

    Conclusions:
    1. Duodenal mass with regional peritonitis and lymphadenopathy – r/o neoplasia vs. gastrointestinal eosinophilic sclerosing fibroplasia vs. chronic foreign body and inflammatory reaction vs. infectious (Histoplasmosis, FIP dry form, other) vs. other

Ultrasound images of the abnormal proximal duodenum and enlarged hypoechoic lymph node adjacent to the duodenal lesion.
Duodenal mass lesion; duodenal mass lesion with more normal appearing duodenal mucosa showing the delineation between the normal and abnormal section.
  • Upper gastrointestinal endoscopy:
    Gastric mucosa and rugal folds appeared normal with no overt erosions or ulcerations noted. Pylorus and pyloric valve appeared normal. Upon entrance into the proximal duodenum, there was a firm mass occluding the duodenal lumen. The mass was pale and very firm at the base making it difficult to biopsy this region. The surface of the mass was brown and smooth. The tissue on the surface of the mass was friable. The duodenal mucosa adjacent to the mass was red to purple and proliferative. A hairball was lodged next to the mass and was removed with the biopsy forceps. The endoscope was able to pass by the mass and the abnormal segment of duodenum (spanned about 2.5-3 cm length) before encountering normal appearing duodenal mucosa. Biopsies of the normal appearing duodenal tissue and multiple biopsies of the mass and surrounding abnormal tissue were obtained.
  • Gastric and duodenal biopsies with histopathology:
    Duodenum: Moderate to severe, eosinophilic, lymphoplasmacytic and neutrophilic enteritis with villous epithelial attenuation, suppurative exudate and spindle cell proliferation with anastomosing collagen bundles

The most significant finding in Boston’s duodenal biopsies was in the duodenum. The mucosal lamina propria contained areas with large numbers of eosinophils and there was evidence of villous epithelial damage. There were also aggregates of luminal suppurative inflammation as well as one fragment of a spindle cell proliferation with features suggestive of, but not definitive for, feline eosinophilic sclerosing fibroplasia (see below). Eosinophilic enteritis has been reported in cats with infectious disease (eg, helminth endoparasitism, toxoplasmosis), food hypersensitivity, hypereosinophilic syndrome and neoplasia (mast cell neoplasia and T cell lymphoma). Eosinophilic GI inflammation can also accompany idiopathic inflammatory bowel disease (IBD) in cats. Peripheral eosinophilia is reported in less than 50% of the cases (6 out of 14 cats in this study). Abdominal lymphadenopathy is frequently observed as well.

Feline gastrointestinal eosinophilic sclerosing fibroplasia (FGESF) is a rare condition characterized histologically by branching and anastomosing trabeculae of collagen surrounded by reactive fibroblasts and varying numbers of eosinophils. FGESF typically forms an ulcerated intramural gastrointestinal mass, but in rare cases has been reported to present with only mesenteric lesions. The stomach and proximal duodenum (pyloroduodenal junction) and ileocecocolic junction are the most common sites affected. Increased numbers of eosinophils may be also be found in regional lymph nodes and other abdominal organs. Etiology is not fully elucidated, but underlying immunological dysregulation has been speculated, and some studies have identified concurrent bacterial infection, or possible foreign material (hair) within the lesions although a causative role has not been demonstrated. Vomiting and weight loss are often the presenting complaints. Patients vary in age from less than 1 year to greater than 15 years old and the prognosis is variable. Treatment is often multimodal (prednisolone, immunomodulatory agents, antibiotics, in conjunction with surgical excision), but treatment efficacy is not established in the literature.

It is important to consider FGESF in cats with intermittent vomiting, weight loss, peripheral eosinophilia and a mass lesion in the gastrointestinal tract on abdominal ultrasound. In the past, it was assumed that many of these lesions were neoplastic, but this may not be the case, especially in a younger cat with peripheral eosinophilia.

Some cats require surgical resection of these lesions, especially obstructive lesions, however given these lesions are often in the proximal duodenum or pylorus, they are not always amenable to surgical resection without risk of significant surgical complications.
Long-term management of FGESF heavily relies on the ongoing use of corticosteroids to prevent the recurrence of masses. In cases where surgery was not followed by corticosteroid therapy, the recurrence of masses or development of new masses, was frequently observed. Long-term management of FGESF heavily relies on the ongoing use of corticosteroids. In one study, 85% of cats that discontinued prednisolone therapy, experienced a recurrence of clinical signs, with a median time of 114 days, before therapy had to be restarted. This emphasizes the necessity of maintaining corticosteroid treatment to achieve sustained control over the disease. The general treatment goal is to reach the lowest effective doses of therapy, reducing the risks of medication side effects while controlling the underlying disease. Secondary immunosuppressive agents and antibiotics have also been utilized in the treatment of FGESF, particularly when prednisolone is contraindicated, such as in pets with pre-existing heart disease or diabetes.

Antibiotics are often administered at the time of initial diagnosis due to evidence of bacterial infection, which is presumed to be secondary to the damage caused by FGESF. Bacterial infection is not indicated in every case of FGESF. Each cat’s experience is unique. Supplemental medications such as anti-nausea and appetite stimulants may also be prescribed as needed.

Dietary modifications have also been explored as an adjunct treatment for FGESF, with improvements seen in some patients. However, it is important to note that most of these cats were also receiving pharmacological intervention, so other variables could have influenced the results. In addition to these treatments, maintaining routine prophylaxis, such as gastrointestinal deworming, is important in managing overall health.

Treatment: Boston received the following treatment.

  • Prednisolone 20 mg/ml: 0.25 ml by mouth twice daily for 1 month and the reduced to 0.25 ml by mouth once daily
  • Boston also received maropitant, Mirataz, and a Convenia injection at the time of endoscopy in case there was a bacterial component to his disease process.

Recheck ultrasounds and exams have continued to be performed and the most recent ultrasound about 6 months after diagnosis showed no evidence of duodenal lesions on ultrasound. Boston is currently on 2.5 mg of prednisolone daily and doing well.

References:

Kambe N et al. (2020), J Small Anim Pract. 2020 Jan;61(1):64-67; Meuten, ed. (2017), Tumors in Domestic Animals, 5th ed., 587; Halsey C et al (2010), Vet Comp Oncol. 2010 Mar;8(1):72-9;

Tucker S, Penninck DG, Keating JH, Webster CR. Clinicopathological and ultrasonographic features of cats with eosinophilic enteritis. J Feline Med Surg. 2014 Dec;16(12):950-6. doi: 10.1177/1098612X14525385. Epub 2014 Mar 3. PMID: 24591305.

Feline Gastrointestinal Eosinophilic Sclerosing Fibroplasia: A resource center for cat caregivers and veterinary professionals. https://www.fgesf.org/