A Rare Case of Cladophialophora caroinii Chromoblastomycosis in a Skin Graft Recipient
Chromoblastomycosis, also called chromomycosis is a subcutaneous chronic mycosis caused by dematiaceous (black) fungi.1 The most frequently isolated organisms are Fonsecaea pedrosoi, Phialophora. verrucosa, Cladosporium carrioni, and less frequently, Rhinocladiella aquaspersa.2 It Progresses slowly and involves exposed body parts. It is characterised by crusted and raised lesions. The fungi present as sclerotic bodies in the lesions, which is a pathognomic feature of this disease. It is distributed worldwide. However it is most commonly seen in tropical and subtropical regions.1 C. caroinii has been reported only sporadically in India in a few case reports.3,4,5,6,7 We present a rare case of chromoblastomycosis by C. caroinii.
A 40 year old male patient, presented to the surgery OPD with cutaneous ulcer over right knee after a fall injury, not associated with fever or pain. The patient was admitted in a tertiary care centre, I.V antibiotics and daily dressing had been done. The swabs from the base of the ulcer had been sent for bacterial culture and sensitivity, shown no growth. After a few days of treatment ulcer was healing with good margins and base.
Patient was discharged with oral antibiotics and anti-inflammatory agents. After one month patient came back for review to OPD with hypopigmented patch over the right knee. The patient was referred to plastic surgery department and skin grafting was done. The graft was taken from the right back. The patient was administered with I.V steroids, antibiotics and oral anti-inflammatory agents. The patient was discharged with oral steroids with tapering dose and antibiotics.
After two weeks period, patient developed soft non-raised fluctuating swelling post skin grafting over the same region (right knee). Differential diagnosis of cutaneous tuberculosis and aspergilloma was made. The FNAC was carried out from the swelling, from which frank pus was aspirated. The pus sample was forwarded for bacterial culture, fungal and mycobacterial culture. The bacterial cultures, both aerobically and anaerobically showed no growth. The sample was negative for acid fast bacilli by Ziehl Neelsen staining. However, KOH mount and Gomori’s methenamine silver (GMS) stain showed septate hyaline hyphae. The GMS stain revealed few grey black round structures measuring around 6-10 µm, suggestive of Medlar or sclerotic or copper penny bodies.
The culture of the pus sample, on Lowenstein-Jensen medium showed no growth after eight weeks of incubation. However, culture on Sabouraud dextrose agar with chloramphenicol revealed slow growing fungus, which was first observed on the tenth day and gradually matured over next three weeks. The growth was initially grey-green which slowly turned to olive-green with cottony folded out texture and with a jet black reverse after three weeks of incubation at 25°C. The lacto phenol cotton blue (LPCB) preparation, from the culture showed septate hyaline hyphae with acropetal long chains of conidia suggestive of Chladophialophora species. The fungus showed growth at 37°C, but not at 42-45°C and urease negative. Based on these findings the fungus was identified as Chladophialophora carrionii.
The patient was diagnosed to have subcutaneous mycosis (chromoblastomycosis) with the presence of sclerotic bodies and the causative organism was identified as Chladophialophora carrionii. The patient was started on oral Itraconazole and he showed good improvement in the condition.
As first described by Medlar in 1915, the term chromoblastomycosis is used for cases in which sclerotic bodies are present in tissue. Sclerotic bodies, also known as Medlar bodies, are globe-shaped, cigar-colored, thick-walled structures that are 4-12 µm in diameter.8 The best name to define the disease was recommended as chromoblastomycosis by the International Society for Human and Animal Mycology (ISHAM).9 The term chromoblastomycosis (chromo – coloured, blasto – budding, mycosis – fungal) was coined by Terra et al in 1922 to define a polymorphic fungal disease located on lower limbs, consisting of nodular or verrucous plaques which could probably ulcerate and develop into hyperkeratosis and acanthosis of the affected epithelial tissues.10 This condition is often misdiagnosed as it is clinically indistinguishable from tuberculosis verrucosa cutis, squamous cell carcinoma, palmo-plantar psoriasis, and sporotrichosis.11,12,13 In this case also, a differential diagnosis of cutaneous tuberculosis was kept in mind. The typical histopathological findings of cutaneous chromoblastomycosis are marked epitheliomatous hyperplasia, microabscesses, chronic granulomatous infiltrates with multinucleate giant cells, epithelioid cells, histiocytes and lymphocytes and presence of copper penny bodies.14 in this case we found septate hyphae and sclerotic bodies on GMS stain of FNAC sample. Certain non-pathogenic or contaminant fungi such as Paecilomyces spp and Penicillium spp. may be sometimes confused with Cladophialophora carrionii. Although both these fungi produce long chains of elliptical conidia, the conidia arise from structures such as metula and phialides, which are not seen in C. carrionii. Both these fungi are rapid growers, unlike C. carrionii, which grows very slowly. Moreover, these non-pathogenic fungi usually form greenish white or greenish brown colonies with no pigment on the reverse, in contrast to the jet black reverse of C. carrionii, which helps in correct identification of this fungi.15 However, C. carrionii should be differentiated from other similar dematiaceous fungi such as Cladophialophora bantiana and Fonsecaea pedrosoi. C. bantiana has the ability to grow at 42-43°C, which can be used to differentiate it from C.carrionii. Unlike Cladophialophora spp., Fonsecaea spp. produce short chains of five or less conidia. Moreover, in Fonsecaea spp. At least two of the three types of anamorphic conidiation (rhinocladiella, phialophora, cladosporium) will be seen.15 Slide culture technique will be useful for proper identification of the above-mentioned features.15 Surgery was considered the treatment of choice for chromoblastomycosis before the advent of triazole antifungal agents.16 However, currently with the availability of potent antifungal agents, chemotherapy has become the first-line of treatment with itraconazole and terbinafine being the drugs of choice, while surgery is used only for limited or small lesions.17 As there have been only few and sporadic case reports of chromoblastomycosis caused by C. caroinii from India, this case reports finds its importance.3,4,5,6,7