Table of Contents  
CASE REPORT
Year : 2014  |  Volume : 7  |  Issue : 5  |  Page : 648-650  

Fungal foot abscess caused by Aureobasidium pullulans culture diagnosis of fine needle aspiration cytology material in a clinically unsuspected patient


1 Department of Pathology, Father Muller Medical College, Mangalore, Karnataka, India
2 Department of Microbiology, Father Muller Medical College, Mangalore, Karnataka, India

Date of Web Publication10-Sep-2014

Correspondence Address:
Hilda Fernandes
Department of Pathology, Father Muller Medical College, Mangalore, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0975-2870.140481

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  Abstract 

Subcutaneous mycosis includes a large spectrum of infections caused by a heterogeneous group of fungi. Fungal infections of the skin can be identified in scrape preparations of lesions and Fine Needle aspirates of abscesses, with recognition of the specific morphological features such as hyphae and branching. We report a fungal abscess caused by Aureobasidium pollulans by smears and culturing the material obtained from Fine Needle Aspiration Cytology.

Keywords: Aureobasidium pollulans (A. pullulans) , FNAC, fungal abscess


How to cite this article:
Fernandes H, Pinto AC, Dias M, Kini R. Fungal foot abscess caused by Aureobasidium pullulans culture diagnosis of fine needle aspiration cytology material in a clinically unsuspected patient. Med J DY Patil Univ 2014;7:648-50

How to cite this URL:
Fernandes H, Pinto AC, Dias M, Kini R. Fungal foot abscess caused by Aureobasidium pullulans culture diagnosis of fine needle aspiration cytology material in a clinically unsuspected patient. Med J DY Patil Univ [serial online] 2014 [cited 2024 Mar 29];7:648-50. Available from: https://journals.lww.com/mjdy/pages/default.aspx/text.asp?2014/7/5/648/140481


  Introduction Top


Subcutaneous mycosis includes a large spectrum of infections caused by a heterogeneous group of fungi. [1] These infections are often chronic, well-localized, involving the skin and subcutaneous tissue. In most of the cases, the patient gives a history of trauma to the involved region. The causative fungi are usually soil saprophytes that are ubiquitous in the environment. The main subcutaneous fungal infections include sporotrichosis, aspergillosis chromoblastomycosis, mycetoma, lobomycosis, rhinosporidiosis, subcutaneous zygomycosis, and subcutaneous phaeohyphomycosis.

In the past few years the incidence of fungal infections has increased; most probably due to the indiscriminate use of broad spectrum antibiotics, increase in the number of immunocompromised patients, travel, and environmental exposure. [2] An increase of 10 to 15 percent in immunocompromised patients has been noted annually.

Fine Needle Aspiration Cytology (FNAC) has emerged as a well-established diagnostic modality for differentiating between neoplastic and infective conditions. Various organisms such as mycobacteria, leishmania, microfilaria, and fungi have been diagnosed based on FNAC findings. [3] The fungal infections of skin can be identified in scrape preparations of lesions and fine needle aspirates of abscesses with the recognition of specific morphological features such as hyphae and branching. [4] The common fungal agents that have been diagnosed by FNAC are Cryptococcus, Coccidioides, Aspergillus, Penicillium marneffei, Rhinosporidium seeberi, Sporothrix schenkii, and many others. [2] Superficial as well as deep-seated masses in almost every organ are accessible by FNAC. Therefore, this procedure can be used to diagnose fungal abscesses.


  Case Report Top


A 68-year-old male presented with a complaint of swelling on the dorsum of his left foot since one year. Initially it was small, but it had been rapidly growing in size since the past few weeks and was associated with pain. The patient was a farmer by occupation and gave a history of working barefoot in the fields. Local examination showed a 3 × 3 cm swelling, with a smooth surface, with well-defined borders, slight tenderness, and no local rise of temperature. The swelling was soft in consistency and the overlying skin was pinchable. It was slightly mobile in the horizontal plane, but not in the vertical plane [Figure 1]a. The patient was an elderly man with a moderate build and nourishment. No pallor, icterus, lymphadenopathy or edema was noticed. The blood counts were within normal limits and he was HIV\HbsAg spot non-reactive. He was referred for FNAC with a clinical diagnosis of lipoma/neurofibroma. FNA was done using a 10 ml disposable syringe and a 23G needle. The aspirated pus-like material was stained with Papanicolaou and May Grunwald Giemsa (MGG) stains. Additional material was collected in a plain vacutainer. The smears showed inflammatory cells, comprising predominantly of neutrophils, macrophages, lymphocytes, and occasional giant cells in a background of necrotic debris [Figure 1]b. A few branching septate fungal hyphae were seen. Material was submitted for fungal culture. The Periodic Acid Schiff (PAS) stain was performed, which showed similar findings [[Figure 1] inset] and confirmed the diagnosis of a fungal abscess. The patient was initially started on antibiotics, which did not relieve his symptoms. However, after FNA diagnosis he was started on fluconazole. A cell block of fluid obtained from the aspirate showed similar features, with a mixed inflammatory infiltrate of neutrophils, lymphocytes, macrophages, multinucleated giant cells, and fibrin. Occasional fragments of fungal hyphae were noted.
Figure 1: (a) Foot swelling (b) Smear showing fungal hyphae in an inflammatory background. (PAP 40X) (c) PAS Stain highlighting fungal hyphae (inset)

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The swelling was excised and sent to the Histopathology Laboratory where it was fixed in 10% formalin, processed, and stained with Hematoxylin and Eosin. The slides showed the epidermis and dermis. The deeper dermis showed dense inflammatory infiltrate composed of neutrophils, eosinophils, lymphocytes, plasma cells, and epithelioid cells. Fungal elements with septate hyphae showing acute angled branching were seen, which was confirmed by using the Gomori's methanamine (GMS) silver stain.

Gram stain or bacterial cultures were not done in this case as a fungal etiology was suspected on MGG smears. The aspirate was inoculated on two plates of Sabouraud dextrose agar (SDA) media, and kept at room temperature and in the incubator, at 25 o C and 37 o C, respectively. After two days, white-to-yellow yeast-like colonies were seen [Figure 2]a. By the end of the week the colonies had turned brown-to-black with a shiny-to-mucoid appearance [Figure 2]b. Lactophenol cotton blue showed a thick septate hyaline hyphae along with arthroconidia (inset). On the basis of the colony and microscopic morphology, the fungus was identified as Aureobasidium pullulans. The patient, who was initially started on antibiotics, was given Tab Fluconazole once it was diagnosed as a fungal abscess. Ten days after excision of the swelling and antifungal therapy, the patient came for follow up and his wound had healed. The sutures were removed and he was advised to continue antifungals for two more weeks.
Figure 2: (a) White-to-yellow yeast like colonies seen after two days (b) Brown-to-black colonies with a shiny-to-mucoid appearance after a week (c) Lactophenol cotton blue showed thick septate hyaline hyphae along with arthroconidia (inset)

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  Discussion Top


A. pullulans is a dematicious fungus, with universal distribution. [5] It is present in the soil, air, food, wood, vegetation, and so on. It is also called 'black yeast' and mostly causes opportunistic infections. Aureobasidium has rarely been associated with human infections, however, cases of the fungus causing keratomycosis, spleen and mandible abscesses, meningitis, subcutaneous mycosis, and peritonitis have been reported. It is also a causative agent of phaeohyphomycosis. It can also cause systemic infections, especially in patients on broad-spectrum antibiotics, invasive devices like central venous catheters, and in immunocompromised patients. However, in the present case, history, examination or investigations done did not reveal any signs of immunodeficiency. Given the history of the patient being an agriculturist and walking in the field barefoot - the most probable route of infection was direct inoculation.

Aureobasidium grows at 25-37 o C on SDA, SDA with antibacterial agents or SDA with cyclohexamide, initially forming moist yeast-like white-to-yellow or pink colonies, which appear wrinkled or with folded topography. Later, arthroconidia are formed and after a few days shiny, mucoid, dark brown-to-black mature colonies appear. [5] The differential diagnoses of black colonies on culture are Exophiala jeanselmei, Exophiala werneckii, Malassezia furfur, Piedraia hortae, Sporothrix schenkii, and Wangiella der matiditis. However, the characteristic microscopic features establish the diagnosis.

Fungal infections can occur in any site and detection of the fungus may give a clue to the patients' condition. [3] FNAC is a boon when it comes to the diagnosis of a variety of fungal diseases and often allows cytological and culture confirmation of the disease so treatment can be started accordingly, as soon as possible. Several cases have been reported proving the efficacy of FNAC in diagnosing localized and systemic mycosis. Subcutaneous lesions caused by Aspergillus, eumycotic mycetoma and acremonium are diagnosed by FNAC. [1],[3],[6] Aspergilloma of the frontal sinus and rhinosporidiosis from a swelling overlying a lytic lesion on the anterior aspect of the tibia have been diagnosed by some. [7],[8]

A few authors have diagnosed A. pullulans by culturing the aspirate obtained from FNAC. Morais et al. reported a case of a 23-year-old patient, on treatment for erythema nodosum, who presented with fever, hoarseness of voice, odynophagia, weight loss, and cervical lymphadenopathy. FNA from the cervical lymph node showed many yeast like forms. The aspirate was cultured and showed A. pullulans. [9] Mise et al. reported a case of peritonitis caused by A. Pullulans in a 37-year-old male patient with chronic glomerulonephritis by aspirating the peritoneal fluid. [10] Joshi et al. reported a case of fever and multiple cutaneous lesions in a pediatric patient having Fanconi anemia, on a conditioning regimen for bone marrow transplantation. Blood culture from the central venous catheter showed fungal growth, which was later diagnosed as A. pullulans. [11] Sakin et al. reported a case of fungal invasion of the lymphatic system by A. pullulans in a patient with histiocytic lymphoma, leading to the formation of a fungal abscess. [9]

On account of the scarcity of cases reported, no universal treatment schedule has been defined. Fluconazole and amphotericin B have shown optimistic outcomes. A combination therapy may be the treatment of choice in the present scenario. [11]


  Conclusion Top


A. pullulans is a saprophytic fungus, which is commonly seen in the environment. However, human infections are rarely reported. Our case shows that FNAC can be the first step to diagnose a fungal infection and can indicate the culture diagnosis of a given fungal species.

 
  References Top

1.Das S, Saha R, Bhattacharya SN, Mishra K, Dar SA. Hyalohyphomycosis: An unusualpresentation and review of literature. IJMS 2010;1:123-9.  Back to cited text no. 1
    
2.Das DK, Grover RK, Chachra KL, Bhatt NC, Misra B. Fine needle aspiration cytology diagnosis of a fungal lesion of the Verticillium species. A case report. ActaCytol1 997; 41:577-82.  Back to cited text no. 2
    
3.Geramizadeh B, Kheirandish P, Fatheezadeh P, Jannesar R. Fine needle aspiration of subcutaneous masses caused by Aspergillus: A report of 2 cases. ActaCytol2005;49:666-8.  Back to cited text no. 3
    
4.Gupta KP, Mcgrath C. Microbiology, inflammation and viral infections. In: Bibbo M, Wilbur D, editors. Comprehensive Cytopathology. 3 rd ed. China:Saunders Elsevier; 2008. p. 91-130.  Back to cited text no. 4
    
5.Fisher F, Cook NB.Some opportunistic fungi.In: Fundamentals of Diagnostic Mycology.1 st ed. Philadelphia: Saunders Elsevier;1998:p.35-58.  Back to cited text no. 5
    
6.Gabhane SK, Gangane N, Anshu. Cytodiagnosis of eumycoticmycetoma. A case report. ActaCytol2008;52:354-6.  Back to cited text no. 6
    
7.KumarBehera S, Patro M, Mishra D, Bal A, Behera B, Sahoo S. Fine needle aspiration in Aspergilloma of frontal sinus. A case report. ActaCytol 2008;52:500-4.  Back to cited text no. 7
    
8.Adiga BK, Singh N, Arora VK, Bhatia A, Jain AK. Rhinosporidiosis. Report of a case with an unusual presentation with bony involvement. ActaCytol1997;41:889-91.  Back to cited text no. 8
    
9.Morais OO, Porto C, Coutinho AS, Reis CM, Teixeira MdeM, Gomes CM. Infection of the lymphatic system by Aureobasidiumpullulans in a patient with erythema nodosumleprosum. Braz J Infect Dis 2011;15:288-92.  Back to cited text no. 9
    
10.Mise N, Ono Y, Kurita N, Sai K, Nishi T, Tagawa H, et al. Aureobasidiumpullulans peritonitis:Case report and review of theliterature. Perit Dial Int2008;28:679-81.  Back to cited text no. 10
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11.Joshi A, Singh R, Shah MS, Umesh S, Khattry N. Subcutaneous mycosis and fungaemia by Aureobasidiumpullulans: A rare pathogenic fungus in a post allogenic BM transplant patient. Bone Marrow Transplant 2010;45:203-4.  Back to cited text no. 11
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    Figures

  [Figure 1], [Figure 2]


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