Indian Journal of Pathology and Microbiology

CASE REPORT
Year
: 2015  |  Volume : 58  |  Issue : 1  |  Page : 115--117

A masquerading subcutaneous swelling caused by Scedosporium apiospermum: An emerging pathogen


A Malini1, NS Madhusudan1, Sankappa P Sinhasan2, Basavanandswamy C Harthimath3,  
1 Department of Microbiology, Indira Gandhi Government Medical College and Research Institute (Government of Puducherry Institute), Puducherry, India
2 Department of Pathology, Indira Gandhi Government Medical College and Research Institute (Government of Puducherry Institute), Puducherry, India
3 Department of Surgery, Indira Gandhi Government Medical College and Research Institute (Government of Puducherry Institute), Puducherry, India

Correspondence Address:
Dr. A Malini
Department of Microbiology, Indira Gandhi Government Medical College and Research Institute (Government of Puducherry Institute), Vazhudavur Road, Kadirkammam, Puducherry - 605 009
India

Abstract

Scedosporiasis is an emerging infection in immunocompromised individuals. We report a case of multiple subcutaneous swellings in a diabetic ketoacidotic patient, which was clinically diagnosed as lipoma. On fine-needle aspiration cytology, pus was aspirated, which showed septate branching hyphal elements. The pus culture on Sabouraud«SQ»s dextrose agar yielded Scedosporium apiospermum, which was identified based on its macroscopic and microscopic features. There are very few reports of scedosporiasis from India. The diagnosis of scedosporiasis is difficult and correct etiological diagnosis can help in better management of the patient.



How to cite this article:
Malini A, Madhusudan N S, Sinhasan SP, Harthimath BC. A masquerading subcutaneous swelling caused by Scedosporium apiospermum: An emerging pathogen.Indian J Pathol Microbiol 2015;58:115-117


How to cite this URL:
Malini A, Madhusudan N S, Sinhasan SP, Harthimath BC. A masquerading subcutaneous swelling caused by Scedosporium apiospermum: An emerging pathogen. Indian J Pathol Microbiol [serial online] 2015 [cited 2021 Apr 22 ];58:115-117
Available from: https://www.ijpmonline.org/text.asp?2015/58/1/115/151206


Full Text

 INTRODUCTION



The genus Scedosporium consists of two important species: Scedosporium prolificans and Scedosporium apiospermum.[1] S. apiospermum is the asexual form of Pseudallesheria boydii.[1],[2],[3] They are ubiquitous in nature found mainly in soil, manure, sewage, and polluted water. S. apiospermum is increasingly being recognized as an important opportunistic fungus. [1] The fungus tolerates high saline content (5%) and it has been recovered from coastal areas. The usual sites of infection are the central nervous system (CNS), eyes, lungs, sinuses, bones, joints, and soft tissues. [1] The diagnosis is generally difficult and is based on histopathological, microbiological and clinical findings. [2],[3] An interesting case of subcutaneous infection due to S. apiospermum is reported here.

 Case Report



A middle aged lady about 56-year-old, an agriculturist by occupation, presented with the complaint of gradually progressive swelling in the right elbow since 2 years. She was a known diabetic and was on irregular treatment. She did not give any history of trauma. On examination, the swelling on the right elbow measuring about 5 cm × 4 cm was tender, there was local rise of temperature and the overlying skin looked normal [Figure 1]. There were also three small (about 1 cm × 2 cm) soft, fluctuant, and tender swellings over the medial aspect of right toe [Figure 1]. Another tender erythematous swelling, with central crusting was noticed over the left lateral malleolus. On further examination, all the finger nails and toe nails were brittle and showed brownish discoloration. These features were suggestive of onychomycosis. A provisional diagnosis of inflammatory swelling/lipoma with diabetes mellitus was made.

The routine hematological investigations were within normal limits. Random blood sugar was 420 mg/dl, fasting blood sugar-111 mg/dl, and postprandial blood sugar-515 mg/dl. The urine sample was positive for ketone bodies.{Figure 1}

Fine needle aspiration cytology (FNAC) from the elbow swelling yielded pus like material. Broad septate hyphal elements in an inflammatory background were seen on microscopic examination [Figure 2].{Figure 2}

The KOH mount of the aspirated pus showed branching septate hyphal elements. The pus sample on bacterial culture did not yield any growth. The sample was inoculated on Sabouraud's dextrose agar (SDA) and incubated at 25°C and 37°C for fungal culture. Colony was faintly visible on 3 rd day, in the SDA tubes incubated at both temperatures. On 5 th day, the colony was greyish white in color and had suede like surface. On the maturation after a week, the obverse was greenish grey in color, surface was suede like and the reverse showed grayish-black discoloration [Figure 3]. Based on the macroscopic appearance, a presumptive diagnosis of phaeohyphomycosis was considered.{Figure 3}

The lactophenol cotton blue mount of slide culture of the fungus on SDA showed irregularly branching septate hyaline hyphae with lateral oval conidia arising singly, as well as terminal conidia arising from conidiophores [Figure 4]. Based on the macroscopic and microscopic morphology, it was identified as S. apiospermum.{Figure 4}

A definitive diagnosis of subcutaneous infection with S. apiospermum with diabetic ketoacidosis was made.

Since the patient had uncontrolled diabetes mellitus with multiple swellings and onychomycosis, we suspected it to be a disseminated fungal infection. Disseminated scedosporiasis is associated with high mortality rate. Therefore, the patient was referred to a higher center for further treatment and was lost for follow-up.

 DISCUSSION



Scedosporium species are found in soil, sewage, and polluted water. [1] Infections due to S. prolificans is more common than S. apiospermum. S. prolificans is classified under demetiaceous fungus. S. apiospermum is considered as a hyaline fungus despite the color of the colony being brownish black. [4] This is because the fungus has colorless mycelium and Fontana-Mason staining for melanin is negative. The color of the colony is due to the production of brown conidia. [5]

The most common mode of infection is by trauma, leading on to cutaneous and subcutaneous infection which may also progress to mycetoma. [1] Infection can also occur due to inhalation of fungal spores. [6] Angioinvasion and neurotropic nature of scedosporiasis have been reported, similar to mucormycosis and aspergillosis. [1] Lymphocutaneous and hematogenous dissemination has also been documented. [5] Disseminated infections have very high mortality rate, nearing to 80%. [1]

The fungus has been recognized as a potent etiological agent of severe infections in immunocompromised individuals and occasionally in immunocompetent patients. In immunocompetent individuals it causes infections like keratitis, endophthalmitis, otitis media, sinusitis, pneumonia after near-drowning. In the immunocompromised host it leads to deep-seated infections with predilection for skin (painful necrotic nodules), lungs, and CNS. [6] Literature search revealed that infections like brain abscess, thyroid abscess, keratomycosis due to S. apiospermum have been reported from India. [7],[8],[9],[10] In our case, it was multiple subcutaneous swellings with onychomycosis in a diabetic ketoacidotic patient.

Currently, Scedosporiosis is one of the common deep mold infections. [5] The diagnosis of Scedosporium infection is often difficult, because clinical features and histopathology are similar to that of Aspergillus, Fusarium and other relatively common hyaline hyphomycetes. [1] Fungal culture helps in establishing the identity of the etiological agent.

Our case is labeled as masquerading swelling because the patient presented with gradually progressive elbow swelling which on initial inspection looked like a lipoma, but on further examination it was found to be inflammatory in nature with local rise of temperature and tenderness. On further examination, multiple swellings on other parts of the body was also noticed. The mode of infection in our case was inconclusive as the patient did not give any history of trauma. The probable risk factors in this case could be uncontrolled diabetes mellitus and the age factor contributing towards immunocompromised condition. In the present case, the patient residing in a coastal area and being an agriculturist, enhances the chance of exposure to these fungi which are prevalent in brackish water and soil rich in organic decomposed material like manure. These fungi are known to grow on the thorns of Acacia tree [1] and these trees are commonly found along the east coast of southern India. As the swellings were seen on the exposed parts of the body, the mode of infection in this case could be thorn pricks during outdoor agricultural activities. However, in this case we could not establish that onychomycosis was due to S. apiospermum as it was not cultured.

The recommended treatment for cutaneous and subcutaneous infections is surgical debridement with antifungal therapy. Voriconazole/posaconazole is recommended and has been used with success. [5] Voriconazole in combination with terbinafine is used in disseminated cases. [6] Unfortunately, we lost the case for follow-up as it was referred to a higher center.

To conclude, this case highlights the point that fungal infections should also be considered in the differential diagnosis of subcutaneous swellings and the importance of FNAC in diagnosing such lesions and also the need to identify the etiological agent for better management of the patient.

References

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