ttp://www.bsava.com
CASE REPORT
Successful treatment of intra-abdominal eumycotic mycetoma caused by Penicillium duponti in a dog J. Janovec, D. J. Brockman*, S. L. Priestnall† and N. J. Kulendra* VRCC Veterinary Referrals, No. 1 Bramston Way, Laindon, Essex, SS15 6TP *Department of Clinical Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA †Department of Pathology and Pathogen Biology, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA
A 2-year-old female neutered golden retriever was presented for investigation of an intra-abdominal mass. Computed tomography revealed a mass associated with the caudal pole of the right kidney. Incisional biopsy findings were consistent with eumycotic mycetoma. The mass was subsequently removed in conjunction with right ureteronephrectomy. Two years later, the dog re-presented with a splenic mass and fungal plaques located throughout the peritoneum. Splenectomy was performed and the mass was diagnosed as eumycotic mycetoma caused by Penicillium duponti. Indefinite systemic treatment with 10 mg/kg itraconazole orally once a day was initiated. Thirty-two months after the last surgery, there were no clinical signs apart from mild polydipsia. Haematology and biochemistry results were unremarkable. To the authors’ knowledge, this is the first report of successful treatment of intraabdominal eumycotic mycetoma with a combination of surgery and systemic antifungal therapy in the dog. Penicillium duponti has not apparently been reported to cause disease in animals or humans. Journal of Small Animal Practice (2016) 57, 159–162 DOI: 10.1111/jsap.12375 Accepted: 7 April 2015; Published online: 27 May 2015
INTRODUCTION Mycetomas are chronic pyogranulomatous lesions containing tissue granules that consist of colonies of organisms and necrotic debris (Greene 2012). Eumycotic mycetomas are caused by fungi and result from traumatic implantation of the fungus into the affected tissue (Reiss et al. 2012). Various fungi have been isolated from such lesions in dogs (Brodey et al. 1955, Seibold 1955, Brodey et al. 1967, Jang & Popp 1970, Kurtz et al. 1970, Coyle 1984, Walker et al. 1988, Allison et al. 1989, Lambrechts et al. 1991, Guillot et al. 2004). This manuscript describes the clinical, ultrasonographic, computed tomographic (CT), surgical and histopathological findings as well as treatment and outcome of a successfully treated case of intra-abdominal eumycotic mycetoma in the dog.
CASE HISTORY A 2-year-old female neutered golden retriever presented to the referring veterinarian with a history of vomiting, diarrhoea, Journal of Small Animal Practice
•
Vol 57
•
March 2016
•
stranguria and haematuria. Abdominal palpation revealed a hard, spherical mass located in the dorsal third of the mid-abdomen. Subsequent exploratory laparotomy revealed a 10-cm diameter mass attached to the right kidney. Histopathological examination of an incisional biopsy sample revealed chronic pyogranulomatous inflammation with numerous fungal hyphae. Other pertinent medical history included abdominal wall wound dehiscence following routine ovariohysterectomy performed at 6 months of age. The dog was referred for further management. Physical examination revealed lethargy, tachycardia, tachypnoea and abdominal pain. Haematology revealed moderate non-regenerative anaemia (HCT 26·2% [37–55%]), leucocytosis (23·1×109/L [6–17·1×109/L]), neutrophilia (15·25×109/L, [3–11·5×109/L]) with a left shift and monocytosis (2·77×109/L [0·15–1·5×109/ L]). Biochemical abnormalities included hypoalbuminaemia (21·4 g/L [28–39 g/L]), hyperglobulinaemia (41·4 g/L [21– 41 g/L]) and increased amylase activity (1867 U/L [176–1245 U/L]). Computed tomography (CT) of the thorax and abdomen revealed sternal lymph node enlargement and a cavitated
© 2015 British Small Animal Veterinary Association
159
J. Janovec et al.
10-cm diameter soft tissue mass associated with the right kidney. The mass was situated in close proximity to the caudal vena cava (Fig 1). An exploratory laparotomy was performed confirming the mass was attached to the right kidney and intimately associated with the caudal vena cava. Right ureteronephrectomy together with excision of the mass was performed. The affected portion of the wall of the vena cava was removed by venotomy after partial occlusion using Satinsky forceps. A mixture of gram positive and gram negative cocci were identified on a Gram-stained impression smear. Histopathological examination was consistent with chronic pyogranulomatous inflammation with extensive fibrosis and numerous aggregates of grey fungal hyphae. Microbial culture of a tissue sample revealed a scant growth of Aspergillus spp. The dog recovered well from surgery and was discharged 6 days post-operatively. Two months after surgery, physical examination, biochemistry and haematology were unremarkable. Two years post-operatively, the dog re-presented with a 1-week history of haemorrhagic diarrhoea and vomiting. Physical examination was unremarkable. A hyperechoic splenic mass of approximately 10 cm in diameter was detected on abdominal ultrasound. Cytology of fine needle aspirates revealed long fungal hyphae. The dog was subsequently referred for further evaluation. At presentation, physical examination was unremarkable. Haematology revealed mild non-regenerative anaemia (haematocrit 31·7% [37–55%]). Biochemistry revealed hypoalbuminaemia (22·1 g/L [28–39 g/L]), hyperglobulinaemia (52·3 g/L [21–41 g/L]) and increased serum amylase activity (1878 U/L [176–1245 U/L]). Serum protein electrophoresis confirmed polyclonal gammopathy. Urinalysis revealed the presence of blood, protein and bacteria; no fungal elements were observed. An abdominal CT was performed under sedation and revealed a 12-cm diameter cavitary soft tissue mass associated with the tail of the spleen with mild contrast uptake (Fig 2); CT of the thorax was unremarkable. Exploratory laparotomy confirmed the 12-cm mass attached to the tail of the spleen and multiple
FIG 1. A transverse CT image of the abdomen showing a soft tissue mass
(M) associated with the right kidney. Note the close proximity of the mass to the caudal vena cava (CVC)
160
omental adhesions. There were multiple 1-mm diameter raised white plaques covering the liver, mesentery and abdominal wall. Routine complete splenectomy was performed (Fig 3). Excisional biopsies of white plaques on the liver and mesentery were taken using a 4-mm skin biopsy punch. Histopathological examination of the spleen revealed multifocal necrosis of the red and white pulp and its replacement by large, scroll-shaped “granules” composed of dense fungal hyphae and occasional conidia embedded in an amorphous eosinophilic material (Splendore-Hoeppli reaction) (Figs 4 and 5). A Grocott stain was used to confirm presence of fungi and revealed numerous septated hyphae (3–6 µm diameter) with acute angle dichotomous branching (Fig 6). Focally in the liver, the parenchyma contained a well circumscribed nodule composed of a core of necrotic cellular debris, bordered by macrophages and activated fibroblasts, encircled by layers of increasingly mature fibrous connective tissue forming a capsule (granuloma). A Grocott stain was
FIG 2. A transverse CT image of the abdomen showing a soft tissue mass (M) associated with the visceral surface of the spleen (S)
FIG 3. Excised spleen with eumycotic mycetoma. Note the granular appearance on the cut surface of the mass
Journal of Small Animal Practice
•
Vol 57
•
March 2016
•
© 2015 British Small Animal Veterinary Association
Intra-abdominal eumycotic mycetoma in a dog
FIG 4. The splenic red and white pulp is multifocally extensively effaced
by multiple pyogranulomas centred upon irregular scrolled mats of fungal hyphae (*). HE ×40
FIG 6. Numerous enmeshed fungal hyphae arranged in large scrolls, surrounded by degenerate and necrotic mixed inflammatory cells. Grocott ×200
urea concentration. Urine obtained by cystocentesis showed no bacterial growth or fungal hyphae. Forty-three months after the splenectomy, the dog was doing well apart from one episode of diarrhoea and mild polydipsia. Haematology and biochemistry were unremarkable.
DISCUSSION
FIG 5. Dense irregular mats of fungal hyphae (*) surrounded by abundant
degenerate neutrophils (n) and bordered by a rim of proliferating fibroblasts (f). HE ×100
negative. The mesenteric biopsy revealed that the adipose tissue was replaced by a disorganised array of proliferating fibroblasts with variable deposition of fibrous connective tissue, mixed with abundant neutrophils and macrophages. A Grocott stain revealed a single fungal hypha embedded within the inflammation. Bacterial culture of the mass was negative after 48 hours. Fungal culture revealed a heavy growth of filamentous fungus identified by rDNA and β-tubulin gene sequencing as P. duponti. The isolate did not grow in any susceptibility system after several attempts. Recovery from splenectomy was uneventful and indefinite systemic therapy with 10 mg/kg itraconazole (Sporonox; Janssen Pharmaceuticals, Inc.) orally once daily was initiated. At 7, 18 and 27 months after the second surgery, abdominal ultrasound, haematology, biochemistry and urinalysis were performed. Ultrasound was unremarkable, haematology and biochemistry revealed mild anaemia, hypercholesterolaemia and a mild elevation in Journal of Small Animal Practice
•
Vol 57
•
March 2016
•
In dogs, intra-abdominal eumycotic mycetoma has been reported very rarely. In four out of five cases published to date, coeliotomy wound dehiscence was identified as the route of infection (Jang & Popp 1970, Kurtz et al. 1970, Walker et al. 1988, Lambrechts et al. 1991). In one case, the peritoneal cavity was contaminated through a perforated duodenum (Allison et al. 1989). In the present case, the first mycetoma presumably developed at the site of the right ovarian stump, which may represent direct implantation of the fungus during the ovariohysterectomy or contamination with environmental fungi following wound dehiscence. The 18-month period between the ovariohysterectomy and the clinical signs may represent the suboptimal environmental conditions for the fungus inside the peritoneal cavity. The optimum temperature for growth of P. duponti is 45–50°C which is higher than the core temperature of a dog (Hashimoto et al. 1972). Penicillium spp. is often confused with Aspergillus spp. on gross or histological appearance, and fungal culture is required to distinguish the two. Fungal culture may be negatively affected by secondary bacterial infection (Greene 2012). In the sample obtained from the nephrectomy, the presence of cocci may have been the reason for only a scant growth of Aspergillus spp. Penicillium duponti was identified in the splenic mass by rDNA and β-tubulin gene sequencing. Whether the second mycetoma was a recurrence of the same disease, caused by the same, initially misdiagnosed fungus inoculated at the time of the ovariohysterectomy, or the two lesions were caused by different microorganisms, with Penicillium spp. having been inoculated during the
© 2015 British Small Animal Veterinary Association
161
J. Janovec et al.
wound dehiscence or the ureteronephrectomy remains unexplained. The original histopathology samples were not available for review. All of the fungal species so far isolated from mycetomas are saprophytic and acquired from the environment (Greene 2012). To the authors’ knowledge, neither P. duponti, nor its teleomorph Talaromyces thermophilus have been reported to cause disease in animals or humans. Penicillium spp. is a common contaminant of body and mucosal surfaces and is considered an opportunistic pathogen (Greene 2012). In immunosuppressed dogs, it can cause disseminated disease (Tomlinson et al. 2011, Caro-Vadillo et al. 2007, Kano et al. 2006, Murphy et al. 2011). Enterococcus species were cultured from the urine at the time of the splenectomy. Disseminated fungal infections can be associated with a generalised immunodeficiency (Day et al. 1986), which may explain the urinary tract infection (UTI) as no immunoglobulin testing was performed. Alternatively, the UTI may be a coincidence as the dog had no history of recurrent UTIs or other infections. Mycotic peritonitis with an intra-abdominal pyogranulomatous “mass-like” lesion involving a mesenteric lymph node was reported as a result of systemic Exophiala dermatitidis fungal infection in a dog (Murphy et al. 2011). Antifungal therapy with voriconazole was used successfully to treat the condition. In eumycotic mycetomas, the formation of typical tissue grains prevents achievement of sufficient levels of an antifungal agent within the mycetoma, therefore, surgical excision of eumycotic mycetoma is recommended (Greene 2012). The prognosis for eumycotic mycetoma is considered poor (Greene 2012). In all but one case published, the dogs were euthanised or died before or soon after surgery. In one case, a combination of surgical excision and fluconazole administration was used (Lambrechts et al. 1991). The dog was euthanised after 7 months of treatment due to liver failure and inability to control the disease; itraconazole was not available at the time of treatment and may have improved the outcome for that case. In the case presented, treatment with systemic antifungal agents was considered unnecessary after removal of the right kidney, because there was no evidence of dissemination, although this subsequently proved incorrect. Itraconazole was initiated following removal of the splenic mass because of dissemination of the disease to other abdominal organs. The combination of surgery to reduce the fungal burden and long-term itraconazole administration may have been the key to the success in this dog. Although controversial because of the long term side effects, indefinite itraconazole administration was chosen as it was impossible to know whether stopping the administration at any stage would lead to recrudescence of the disease. Nevertheless, indefinite treatment may not be necessary in all cases. No data is available in the literature about the susceptibility of P. duponti and, unfortunately, the fungus did not grow in any susceptibility system despite several attempts. Itraconazole was chosen as it possesses very good activity against filamentous fungi.
162
Itraconazole is potentially hepatotoxic; hence periodic monitoring of liver enzyme activities was performed. Other azole derivatives such as fluconazole or voriconazole represent alternatives.
CONCLUSIONS Although rare, eumycotic mycetoma should be included in a list of differential diagnoses for an intra-abdominal mass. In dogs, long-term systemic antifungal therapy should be considered to increase the survival time following surgical excision, particularly in cases of disseminated disease. This is the first report of P. duponti as a pathogen as well as the first report of successful long-term management of an intra-abdominal eumycotic mycetoma in the dog using a combination of surgery and systemic antifungal therapy. Conflict of interest None of the authors of this article has a financial or personal relationship with other people or organisations that could inappropriately influence or bias the content of the paper. References Allison, N., McDonald, R. K., Guist, S. R., et al. (1989) Eumycotic mycetoma caused by Pseudallescheria boydii in a dog. Journal of American Veterinary Medical Association 194, 797-799 Brodey, R. S., Cole, E. J. & Sauer, R. M. (1955) Nocardial mycetoma in a dog. Journal of American Veterinary Medical Association 127, 433-434 Brodey, R. S., Schryver, H. F., Deubler, M. J., et al. (1967) Mycetoma in a dog. Journal of American Veterinary Medical Association 151, 442-451 Caro-Vadillo, A., Paya-Vicens, M. J., Martinez-Merlo, E., et al. (2007) Fungal pneumonia caused by Penicillium brevicompactum in a young Staffordshire bull terrier. Veterinary Record 160, 595-596 Coyle, V. (1984) Canine mycetoma: a case report and review of the literature. Journal of Small Animal Practice 25, 261-268 Day, M. J., Penhale, W. J., Eger, C. E., et al. (1986) Disseminated aspergillosis in dogs. Australian Veterinary Journal 63, 55-59 Greene, C. E. (2012) Infectious Diseases of the Dog and Cat. St. Louis, MO, USA: Elsevier/Saunders Guillot, J., Garcia-Hermoso, D., Degorce, F., et al. (2004) Eumycetoma caused by Cladophialophora bantiana in a dog. Journal of Clinical Microbiology 42, 4901-4903 Hashimoto, H., Iwaasa, T. & Yokotsuka, T. (1972) Thermostable acid protease produced by Penicillium duponti K1014, a true thermophilic fungus newly isolated from compost. Applied Microbiology 24, 986-992 Jang, S. S. & Popp, J. A. (1970) Eumycotic mycetoma in a dog caused by Allescheria boydii. Journal of American Veterinary Medical Association 157, 1071-1076 Kano, R., Ito, K., Imagi, M., et al. (2006) Isolation of Penicillium commune from a pulmonary infection in a dog. Veterinary Record 159, 779-780 Kurtz, H. J., Finco, D. R. & Perman, V. (1970) Maduromycosis (Allescheria boydii) in a dog. Journal of American Veterinary Medical Association 157, 917-921 Lambrechts, N., Collett, M. G. & Henton, M. (1991) Black grain eumycetoma (Madurella mycetomatis) in the abdominal cavity of a dog. Journal of Medical Veterinary Mycology 29, 211-214 Murphy, K. F., Malik, R., Barnes, A., et al. (2011) Successful treatment of intraabdominal Exophiala dermatitidis infection in a dog. Veterinary Record 168, 217 Reiss, E., Shadomy, H. J. & Lyon, G. M. (2012) Fundamental Medical Mycology. Hoboken, NJ, USA: John Wiley & Sons Seibold, H. R. (1955) Mycetoma in a dog. Journal of American Veterinary Medical Association 127, 444-445 Tomlinson, J. K., Cooley, A. J., Zhang, S., et al. (2011) Granulomatous lymphadenitis caused by Talaromyces helicus in a Labrador Retriever. Veterinary Clinical Pathology 40, 553-557 Walker, R. L., Monticello, T. M., Ford, R. B., et al. (1988) Eumycotic mycetoma caused by Pseudallescheria boydii in the abdominal cavity of a dog. Journal of American Veterinary Medical Association 192, 67-70
Journal of Small Animal Practice
•
Vol 57
•
March 2016
•
© 2015 British Small Animal Veterinary Association
CASE REPORT
Successful treatment of intra-abdominal eumycotic mycetoma caused by Penicillium duponti in a dog J. Janovec, D. J. Brockman*, S. L. Priestnall† and N. J. Kulendra* VRCC Veterinary Referrals, No. 1 Bramston Way, Laindon, Essex, SS15 6TP *Department of Clinical Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA †Department of Pathology and Pathogen Biology, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA
A 2-year-old female neutered golden retriever was presented for investigation of an intra-abdominal mass. Computed tomography revealed a mass associated with the caudal pole of the right kidney. Incisional biopsy findings were consistent with eumycotic mycetoma. The mass was subsequently removed in conjunction with right ureteronephrectomy. Two years later, the dog re-presented with a splenic mass and fungal plaques located throughout the peritoneum. Splenectomy was performed and the mass was diagnosed as eumycotic mycetoma caused by Penicillium duponti. Indefinite systemic treatment with 10 mg/kg itraconazole orally once a day was initiated. Thirty-two months after the last surgery, there were no clinical signs apart from mild polydipsia. Haematology and biochemistry results were unremarkable. To the authors’ knowledge, this is the first report of successful treatment of intraabdominal eumycotic mycetoma with a combination of surgery and systemic antifungal therapy in the dog. Penicillium duponti has not apparently been reported to cause disease in animals or humans. Journal of Small Animal Practice (2016) 57, 159–162 DOI: 10.1111/jsap.12375 Accepted: 7 April 2015; Published online: 27 May 2015
INTRODUCTION Mycetomas are chronic pyogranulomatous lesions containing tissue granules that consist of colonies of organisms and necrotic debris (Greene 2012). Eumycotic mycetomas are caused by fungi and result from traumatic implantation of the fungus into the affected tissue (Reiss et al. 2012). Various fungi have been isolated from such lesions in dogs (Brodey et al. 1955, Seibold 1955, Brodey et al. 1967, Jang & Popp 1970, Kurtz et al. 1970, Coyle 1984, Walker et al. 1988, Allison et al. 1989, Lambrechts et al. 1991, Guillot et al. 2004). This manuscript describes the clinical, ultrasonographic, computed tomographic (CT), surgical and histopathological findings as well as treatment and outcome of a successfully treated case of intra-abdominal eumycotic mycetoma in the dog.
CASE HISTORY A 2-year-old female neutered golden retriever presented to the referring veterinarian with a history of vomiting, diarrhoea, Journal of Small Animal Practice
•
Vol 57
•
March 2016
•
stranguria and haematuria. Abdominal palpation revealed a hard, spherical mass located in the dorsal third of the mid-abdomen. Subsequent exploratory laparotomy revealed a 10-cm diameter mass attached to the right kidney. Histopathological examination of an incisional biopsy sample revealed chronic pyogranulomatous inflammation with numerous fungal hyphae. Other pertinent medical history included abdominal wall wound dehiscence following routine ovariohysterectomy performed at 6 months of age. The dog was referred for further management. Physical examination revealed lethargy, tachycardia, tachypnoea and abdominal pain. Haematology revealed moderate non-regenerative anaemia (HCT 26·2% [37–55%]), leucocytosis (23·1×109/L [6–17·1×109/L]), neutrophilia (15·25×109/L, [3–11·5×109/L]) with a left shift and monocytosis (2·77×109/L [0·15–1·5×109/ L]). Biochemical abnormalities included hypoalbuminaemia (21·4 g/L [28–39 g/L]), hyperglobulinaemia (41·4 g/L [21– 41 g/L]) and increased amylase activity (1867 U/L [176–1245 U/L]). Computed tomography (CT) of the thorax and abdomen revealed sternal lymph node enlargement and a cavitated
© 2015 British Small Animal Veterinary Association
159
J. Janovec et al.
10-cm diameter soft tissue mass associated with the right kidney. The mass was situated in close proximity to the caudal vena cava (Fig 1). An exploratory laparotomy was performed confirming the mass was attached to the right kidney and intimately associated with the caudal vena cava. Right ureteronephrectomy together with excision of the mass was performed. The affected portion of the wall of the vena cava was removed by venotomy after partial occlusion using Satinsky forceps. A mixture of gram positive and gram negative cocci were identified on a Gram-stained impression smear. Histopathological examination was consistent with chronic pyogranulomatous inflammation with extensive fibrosis and numerous aggregates of grey fungal hyphae. Microbial culture of a tissue sample revealed a scant growth of Aspergillus spp. The dog recovered well from surgery and was discharged 6 days post-operatively. Two months after surgery, physical examination, biochemistry and haematology were unremarkable. Two years post-operatively, the dog re-presented with a 1-week history of haemorrhagic diarrhoea and vomiting. Physical examination was unremarkable. A hyperechoic splenic mass of approximately 10 cm in diameter was detected on abdominal ultrasound. Cytology of fine needle aspirates revealed long fungal hyphae. The dog was subsequently referred for further evaluation. At presentation, physical examination was unremarkable. Haematology revealed mild non-regenerative anaemia (haematocrit 31·7% [37–55%]). Biochemistry revealed hypoalbuminaemia (22·1 g/L [28–39 g/L]), hyperglobulinaemia (52·3 g/L [21–41 g/L]) and increased serum amylase activity (1878 U/L [176–1245 U/L]). Serum protein electrophoresis confirmed polyclonal gammopathy. Urinalysis revealed the presence of blood, protein and bacteria; no fungal elements were observed. An abdominal CT was performed under sedation and revealed a 12-cm diameter cavitary soft tissue mass associated with the tail of the spleen with mild contrast uptake (Fig 2); CT of the thorax was unremarkable. Exploratory laparotomy confirmed the 12-cm mass attached to the tail of the spleen and multiple
FIG 1. A transverse CT image of the abdomen showing a soft tissue mass
(M) associated with the right kidney. Note the close proximity of the mass to the caudal vena cava (CVC)
160
omental adhesions. There were multiple 1-mm diameter raised white plaques covering the liver, mesentery and abdominal wall. Routine complete splenectomy was performed (Fig 3). Excisional biopsies of white plaques on the liver and mesentery were taken using a 4-mm skin biopsy punch. Histopathological examination of the spleen revealed multifocal necrosis of the red and white pulp and its replacement by large, scroll-shaped “granules” composed of dense fungal hyphae and occasional conidia embedded in an amorphous eosinophilic material (Splendore-Hoeppli reaction) (Figs 4 and 5). A Grocott stain was used to confirm presence of fungi and revealed numerous septated hyphae (3–6 µm diameter) with acute angle dichotomous branching (Fig 6). Focally in the liver, the parenchyma contained a well circumscribed nodule composed of a core of necrotic cellular debris, bordered by macrophages and activated fibroblasts, encircled by layers of increasingly mature fibrous connective tissue forming a capsule (granuloma). A Grocott stain was
FIG 2. A transverse CT image of the abdomen showing a soft tissue mass (M) associated with the visceral surface of the spleen (S)
FIG 3. Excised spleen with eumycotic mycetoma. Note the granular appearance on the cut surface of the mass
Journal of Small Animal Practice
•
Vol 57
•
March 2016
•
© 2015 British Small Animal Veterinary Association
Intra-abdominal eumycotic mycetoma in a dog
FIG 4. The splenic red and white pulp is multifocally extensively effaced
by multiple pyogranulomas centred upon irregular scrolled mats of fungal hyphae (*). HE ×40
FIG 6. Numerous enmeshed fungal hyphae arranged in large scrolls, surrounded by degenerate and necrotic mixed inflammatory cells. Grocott ×200
urea concentration. Urine obtained by cystocentesis showed no bacterial growth or fungal hyphae. Forty-three months after the splenectomy, the dog was doing well apart from one episode of diarrhoea and mild polydipsia. Haematology and biochemistry were unremarkable.
DISCUSSION
FIG 5. Dense irregular mats of fungal hyphae (*) surrounded by abundant
degenerate neutrophils (n) and bordered by a rim of proliferating fibroblasts (f). HE ×100
negative. The mesenteric biopsy revealed that the adipose tissue was replaced by a disorganised array of proliferating fibroblasts with variable deposition of fibrous connective tissue, mixed with abundant neutrophils and macrophages. A Grocott stain revealed a single fungal hypha embedded within the inflammation. Bacterial culture of the mass was negative after 48 hours. Fungal culture revealed a heavy growth of filamentous fungus identified by rDNA and β-tubulin gene sequencing as P. duponti. The isolate did not grow in any susceptibility system after several attempts. Recovery from splenectomy was uneventful and indefinite systemic therapy with 10 mg/kg itraconazole (Sporonox; Janssen Pharmaceuticals, Inc.) orally once daily was initiated. At 7, 18 and 27 months after the second surgery, abdominal ultrasound, haematology, biochemistry and urinalysis were performed. Ultrasound was unremarkable, haematology and biochemistry revealed mild anaemia, hypercholesterolaemia and a mild elevation in Journal of Small Animal Practice
•
Vol 57
•
March 2016
•
In dogs, intra-abdominal eumycotic mycetoma has been reported very rarely. In four out of five cases published to date, coeliotomy wound dehiscence was identified as the route of infection (Jang & Popp 1970, Kurtz et al. 1970, Walker et al. 1988, Lambrechts et al. 1991). In one case, the peritoneal cavity was contaminated through a perforated duodenum (Allison et al. 1989). In the present case, the first mycetoma presumably developed at the site of the right ovarian stump, which may represent direct implantation of the fungus during the ovariohysterectomy or contamination with environmental fungi following wound dehiscence. The 18-month period between the ovariohysterectomy and the clinical signs may represent the suboptimal environmental conditions for the fungus inside the peritoneal cavity. The optimum temperature for growth of P. duponti is 45–50°C which is higher than the core temperature of a dog (Hashimoto et al. 1972). Penicillium spp. is often confused with Aspergillus spp. on gross or histological appearance, and fungal culture is required to distinguish the two. Fungal culture may be negatively affected by secondary bacterial infection (Greene 2012). In the sample obtained from the nephrectomy, the presence of cocci may have been the reason for only a scant growth of Aspergillus spp. Penicillium duponti was identified in the splenic mass by rDNA and β-tubulin gene sequencing. Whether the second mycetoma was a recurrence of the same disease, caused by the same, initially misdiagnosed fungus inoculated at the time of the ovariohysterectomy, or the two lesions were caused by different microorganisms, with Penicillium spp. having been inoculated during the
© 2015 British Small Animal Veterinary Association
161
J. Janovec et al.
wound dehiscence or the ureteronephrectomy remains unexplained. The original histopathology samples were not available for review. All of the fungal species so far isolated from mycetomas are saprophytic and acquired from the environment (Greene 2012). To the authors’ knowledge, neither P. duponti, nor its teleomorph Talaromyces thermophilus have been reported to cause disease in animals or humans. Penicillium spp. is a common contaminant of body and mucosal surfaces and is considered an opportunistic pathogen (Greene 2012). In immunosuppressed dogs, it can cause disseminated disease (Tomlinson et al. 2011, Caro-Vadillo et al. 2007, Kano et al. 2006, Murphy et al. 2011). Enterococcus species were cultured from the urine at the time of the splenectomy. Disseminated fungal infections can be associated with a generalised immunodeficiency (Day et al. 1986), which may explain the urinary tract infection (UTI) as no immunoglobulin testing was performed. Alternatively, the UTI may be a coincidence as the dog had no history of recurrent UTIs or other infections. Mycotic peritonitis with an intra-abdominal pyogranulomatous “mass-like” lesion involving a mesenteric lymph node was reported as a result of systemic Exophiala dermatitidis fungal infection in a dog (Murphy et al. 2011). Antifungal therapy with voriconazole was used successfully to treat the condition. In eumycotic mycetomas, the formation of typical tissue grains prevents achievement of sufficient levels of an antifungal agent within the mycetoma, therefore, surgical excision of eumycotic mycetoma is recommended (Greene 2012). The prognosis for eumycotic mycetoma is considered poor (Greene 2012). In all but one case published, the dogs were euthanised or died before or soon after surgery. In one case, a combination of surgical excision and fluconazole administration was used (Lambrechts et al. 1991). The dog was euthanised after 7 months of treatment due to liver failure and inability to control the disease; itraconazole was not available at the time of treatment and may have improved the outcome for that case. In the case presented, treatment with systemic antifungal agents was considered unnecessary after removal of the right kidney, because there was no evidence of dissemination, although this subsequently proved incorrect. Itraconazole was initiated following removal of the splenic mass because of dissemination of the disease to other abdominal organs. The combination of surgery to reduce the fungal burden and long-term itraconazole administration may have been the key to the success in this dog. Although controversial because of the long term side effects, indefinite itraconazole administration was chosen as it was impossible to know whether stopping the administration at any stage would lead to recrudescence of the disease. Nevertheless, indefinite treatment may not be necessary in all cases. No data is available in the literature about the susceptibility of P. duponti and, unfortunately, the fungus did not grow in any susceptibility system despite several attempts. Itraconazole was chosen as it possesses very good activity against filamentous fungi.
162
Itraconazole is potentially hepatotoxic; hence periodic monitoring of liver enzyme activities was performed. Other azole derivatives such as fluconazole or voriconazole represent alternatives.
CONCLUSIONS Although rare, eumycotic mycetoma should be included in a list of differential diagnoses for an intra-abdominal mass. In dogs, long-term systemic antifungal therapy should be considered to increase the survival time following surgical excision, particularly in cases of disseminated disease. This is the first report of P. duponti as a pathogen as well as the first report of successful long-term management of an intra-abdominal eumycotic mycetoma in the dog using a combination of surgery and systemic antifungal therapy. Conflict of interest None of the authors of this article has a financial or personal relationship with other people or organisations that could inappropriately influence or bias the content of the paper. References Allison, N., McDonald, R. K., Guist, S. R., et al. (1989) Eumycotic mycetoma caused by Pseudallescheria boydii in a dog. Journal of American Veterinary Medical Association 194, 797-799 Brodey, R. S., Cole, E. J. & Sauer, R. M. (1955) Nocardial mycetoma in a dog. Journal of American Veterinary Medical Association 127, 433-434 Brodey, R. S., Schryver, H. F., Deubler, M. J., et al. (1967) Mycetoma in a dog. Journal of American Veterinary Medical Association 151, 442-451 Caro-Vadillo, A., Paya-Vicens, M. J., Martinez-Merlo, E., et al. (2007) Fungal pneumonia caused by Penicillium brevicompactum in a young Staffordshire bull terrier. Veterinary Record 160, 595-596 Coyle, V. (1984) Canine mycetoma: a case report and review of the literature. Journal of Small Animal Practice 25, 261-268 Day, M. J., Penhale, W. J., Eger, C. E., et al. (1986) Disseminated aspergillosis in dogs. Australian Veterinary Journal 63, 55-59 Greene, C. E. (2012) Infectious Diseases of the Dog and Cat. St. Louis, MO, USA: Elsevier/Saunders Guillot, J., Garcia-Hermoso, D., Degorce, F., et al. (2004) Eumycetoma caused by Cladophialophora bantiana in a dog. Journal of Clinical Microbiology 42, 4901-4903 Hashimoto, H., Iwaasa, T. & Yokotsuka, T. (1972) Thermostable acid protease produced by Penicillium duponti K1014, a true thermophilic fungus newly isolated from compost. Applied Microbiology 24, 986-992 Jang, S. S. & Popp, J. A. (1970) Eumycotic mycetoma in a dog caused by Allescheria boydii. Journal of American Veterinary Medical Association 157, 1071-1076 Kano, R., Ito, K., Imagi, M., et al. (2006) Isolation of Penicillium commune from a pulmonary infection in a dog. Veterinary Record 159, 779-780 Kurtz, H. J., Finco, D. R. & Perman, V. (1970) Maduromycosis (Allescheria boydii) in a dog. Journal of American Veterinary Medical Association 157, 917-921 Lambrechts, N., Collett, M. G. & Henton, M. (1991) Black grain eumycetoma (Madurella mycetomatis) in the abdominal cavity of a dog. Journal of Medical Veterinary Mycology 29, 211-214 Murphy, K. F., Malik, R., Barnes, A., et al. (2011) Successful treatment of intraabdominal Exophiala dermatitidis infection in a dog. Veterinary Record 168, 217 Reiss, E., Shadomy, H. J. & Lyon, G. M. (2012) Fundamental Medical Mycology. Hoboken, NJ, USA: John Wiley & Sons Seibold, H. R. (1955) Mycetoma in a dog. Journal of American Veterinary Medical Association 127, 444-445 Tomlinson, J. K., Cooley, A. J., Zhang, S., et al. (2011) Granulomatous lymphadenitis caused by Talaromyces helicus in a Labrador Retriever. Veterinary Clinical Pathology 40, 553-557 Walker, R. L., Monticello, T. M., Ford, R. B., et al. (1988) Eumycotic mycetoma caused by Pseudallescheria boydii in the abdominal cavity of a dog. Journal of American Veterinary Medical Association 192, 67-70
Journal of Small Animal Practice
•
Vol 57
•
March 2016
•
© 2015 British Small Animal Veterinary Association
