Use of a combination of prednisolone and rosuvastatin for treatment of a pyogranuloma in a dog.

CASE DESCRIPTION: A 6-year-old spayed female Miniature Dachshund was examined because of a 3-day history of anorexia and diarrhea. CLINICAL FINDINGS: A lump was detected during abdominal palpation. Biochemical abnormalities included increases in serum concentrations of total protein, globulin, and C-reactive protein (CRP). Abdominal radiography and abdominal ultrasonography revealed a mass on the caudal aspect of the right kidney. Exploratory laparotomy confimed the mass; however, it could not be excised because it was strongly adhered to surrounding tissues. Histologic examination of a tissue sample from the mass led to a diagnosis of pyogranuloma. TREATMENT AND OUTCOME: The dog was treated with rosuvastatin, but no improvement was evident. Administration of a high dose of prednisolone (1 mg/kg [0.45 mg/lb], PO, q 12 h) was initiated. The CRP concentration returned to within reference limits, and the mass gradually decreased in size. The prednisolone dosage was tapered to 0.14 mg/kg (0.064 mg/lb), PO, every 12 hours. However, once the low dosage of prednisolone was reached, CRP concentration and size of the mass increased. Rosuvastatin was subsequently combined with the low dosage of prednisolone. After 1 week of the combination treatment, the CRP concentration returned to within reference limits, and the mass was reduced in size. The mass eventually could not be detected ultrasonographically. CLINICAL RELEVANCE: A low dose of prednisolone was not effective against the pyogranuloma. However, administration of a low dose of prednisolone in combination with rosuvastatin caused decreases in CRP concentration and size of the pyogranuloma. Thus, statins may act as immunosuppressants.