Diagnosis and management of a case of retroperitoneal eosinophilic sclerosing fibroplasia in a cat

Abstract

Case summary: A 4-year-old neutered male cat was presented with a 2-month history of intermittent constipation that progressed to obstipation. Primary clinical findings included a large, multi lobulated mass in the caudodorsal abdomen, peripheral eosinophilia and hyperglobulinemia. Abdominal imaging revealed a multilobulated, cavitated mass in the sublumbar region. Exploratory celiotomy revealed multiple firm masses in the sublumbar retroperitoneal space causing ventral displacement and compression of the descending colon with extension of the masses into the pelvic canal. Histopathology was consistent with feline gastrointestinal eosinophilic sclerosing fibroplasia (FGESF). Aerobic culture was positive for Staphylococcus aureus. The cat was treated with prednisolone (2 mg/kg PO q24h), lactulose (0.5 g/kg PO q8h), amoxicillin/clavulanic acid (62.5 mg/cat PO q12h for 1 month) and fenbendazole (50 mg/kg PO q24h for 5 days). Six months postoperatively, the cat had no recurrence of clinical signs. Repeat evaluation and imaging at day 732 postoperatively revealed marked improvement of the abdominal mass, resolution of peripheral eosinophilia and no clinical signs with continued prednisolone therapy (0.5 mg/kg PO q24h).

Relevance and novel information: This is a report of a primary extramural FGESF lesion, and the first description of characteristics of FGESF on CT. Previous evidence suggests that the most favorable outcomes require immunosuppressive therapy and complete surgical excision; however, this case demonstrates a favorable outcome with medical management alone.

Keywords: Gastrointestinal; eosinophilic sclerosing fibroplasia; medical; surgery.

Figure 1

(a) Right lateral, (b) left lateral and (c) ventrodorsal radiographic projections of the abdomen. The descending colon is ventrally displaced and the urinary bladder is cranially displaced. The colon contains a large amount of heterogeneous feces and gas, and becomes narrowed at the level of the lesion

Figure 2

Examples of a (a) transverse and (b) sagittal slice obtained by abdominal CT. The multilobulated, heterogeneous soft tissue mass (white arrows) present in the caudal abdomen extends into the pelvic canal dorsal to the rectum and urethra and continues caudally just cranial to the anus

Figure 3

Photomicrographs of an excisional biopsy specimen of one of the sublumbar masses in the cat. (a) The well-circumscribed mass consists of sclerotic fibrous tissue with central necrosis. Hematoxylin and eosin stain; bar = 1 mm. (b) Hypertrophied fibroblasts are in the sclerotic tissue and in the scattered foci of eosinophilic inflammation. Hematoxylin and eosin stain; bar = 60 μm. (inset) Higher magnification of an aggregate of eosinophils mixed with other leukocytes and fibroblasts. Hematoxylin and eosin stain; bar = 25 μm

Figure 4

(a) Transverse and (b) sagittal post-contrast abdominal CT images at 732 days postoperatively. There is a single ovoid contrast-enhancing, soft tissue-attenuating mass (white arrows) present within the pelvic canal causing ventral displacement and narrowing of the rectum at the level of the sacrum