Mycetoma-Like Chromoblastomycosis: A Diagnostic Dilemma: Tropical Medicine Rounds
Mycetoma-Like Chromoblastomycosis: A Diagnostic Dilemma: Tropical Medicine Rounds
Mycetoma-Like Chromoblastomycosis: A Diagnostic Dilemma: Tropical Medicine Rounds
(a) Discussion
Dematiaceous or pigmented fungi cause a variety of subcuta-
neous fungal diseases – mycetoma, chromoblastomycosis, and
pheohyphomycosis being important among them. Mycetoma
presents as a chronic indurated swelling with discharging
sinuses usually involving the lower extremities. The hallmark
triad of the disease is tumefaction, fistulization of the abscess,
and extrusion of colored grains.3,4 Grains, also known as sclero-
tia, are aggregates of the fungal hyphae or bacterial filaments,
sometimes embedded in tough, cement-like material.5 It extends
and slowly invades the subcutaneous tissue, fat, ligaments,
muscle, and bone. The infection is not self-curing and, if
untreated, leads to massive lesions, which may in the end
necessitate surgical amputation.6 Madurella mycetomatis,
Madurella grisea, pseudallescheria boydii, leptosphaeria sene-
(b) galensis, and Acremonium are some of the important fungal
agents causing eumycotic mycetoma, whereas Nocardia, Actino-
madura, and Streptomyces are common agents causing actino-
mycotic mycetoma. Histologically, there is chronic inflammatory
reaction with suppurative granuloma formation and granules
containing either thick-walled septate hyphae as in eumycotic
mycetoma or fine branching interlacing filaments as in actinomy-
cotic mycetoma.
Chromoblastomycosis, on the other hand, presents as a
hypertrophic verrucous plaque at sites prone to trauma com-
monly on feet, legs, arms, face, and neck.7 It may ulcerate or
(c) develop atrophy and scarring. Satellite lesions are produced by
scratching, and there may be lymphatic spread to adjacent
areas. It can also present in varied morphologies like nodular,
tumoral, cicatricial, plaque, and verrucous.8–10 The common cau-
sative agents include Fonsecaea pedrosoi, Cladophialophora
carrionii, Phialophora verrucosa, Rhinocladiella aquaspersa, and
Fonsecaea compacta. Irrespective of the species, the pathogen
can be demonstrated as deeply pigmented thick-walled muriform
or sclerotic bodies. They are seen either in giant cells or neu-
trophilic abscesses in histopathology.11 Demonstration of muri-
form body in scrape smear, histopathology, or in aspiration
cytology is diagnostic of chromoblastomycosis.12
In our case, although the clinical presentation showed close
resemblance to mycetoma, typical granules were not demon-
Figure 1 (a) Skin biopsy showing granuloma in the dermis with
strated, which pointed against a diagnosis of mycetoma. Diag-
Langhans giant cell containing sclerotic body (H&E; 940). (b) Gray-
black velvetty colonies on tube culture with a jet black reverse. (c) nosis of chromoblastomycosis was confirmed through
Microscopy showing septate hyphae with sympodial and acropetal histopathology, which showed sclerotic bodies, and fungal
type of conidiation (lactophenol cotton blue mount, 940) culture, which demonstrated the causative agent Fonsecea
pedrosoi.
be seen. Specimens were also sent for fungal and mycobacte- The reason for such an altered presentation may be related
rial culture. Within 3 weeks, culture in Sabouraud’s dextrose to the underlying immunological mechanism. It is assumed that
agar showed olive gray colonies with jet black in reverse genetic susceptibility of the host, virulence of the organism, and
(Fig. 1b), and lactophenol cotton blue mount of the same host immunity are important factors determining the clinical and
showed septate branching hyphae with sympodial histological presentation of the disease. Tsuneto et al.13 have
(Rhinocladiella) and acropetal (cladosporium) type of conidiation enumerated the role of HLA-A29 A in susceptibility to chro-
typical of Fonsecaea pedrosoi (Fig. 1c). moblastomycosis. Though the first line of defense against fungi
(a) levels of IL-10 and low IFN-c, whereas mild forms are associ-
ated with low levels of IL-10 and higher IFN-c, thereby indicating
a crucial role of IFN-c and CD4 + T lymphocytes in the immune
response against chromoblastomycosis.
Pregnancy is associated with immunosuppression often sub-
jecting the patient to increased risk of infection. There is a shift
in the immunological profile toward Th2 response in pregnancy
with elevated IL-10 levels,16 and it would be reasonable to pos-
tulate that this shift in immunological profile accounted for the
severe form of the disease with deeper tissue involvement and
rapid progression of the condition.
Dematiaceous fungi are increasingly being recognized as an
important pathogen in human infections especially in the past
few decades. A case of disseminated Phaeohyphomycosis
because of Exophiala spinifera during pregnancy was reported
by Ricardo et al.,17 and a case of concurrent mycetoma and
(b) chromoblastomycosis was reported by Murthy et al.,18 but a
mycetoma-like presentation of chromoblastomycosis is yet to be
reported. It is said that chromoblastomycosis and pheohy-
phomycosis represent two poles of a spectrum of disease
caused by pigmented fungi.19 So, we assume that the spectrum
of diseases caused by dematiaceous fungi has no strict boun-
dries, and a mycetoma-like presentation may be induced by
F. pedrosoi during immunosuppression. Interestingly, Exophiala
jeanselmei is a black fungi which is known to cause all three
conditions.6
Both itraconazole and terbinafine have been used success-
fully in the treatment of chromoblastomycosis. Potassium
(c) iodide is another effective drug for chromoblastomycosis
caused by F. pedrosoi. The therapeutic responses to itracona-
zole and ter-binafine are thought to be better if the causative
agent is C.carrionii.20 Other options include surgical excision,
cryotherapy, local application of heat, and CO2 laser vaporiza-
tion. They are useful only in smaller lesions. Our patient was
treated with terbinafine 250 mg daily in the postnatal period,
and she showed an excellent response within 6 months
(Fig. 2c).
Conclusion
Figure 2 (a & b) Indurated swelling with multiple discharging This unusual clinical setting reiterates the need to be vigilant
sinuses around right ankle. (c) After 6 months of treatment with about the atypical presentations of well-known dermatological
Terbinafine conditions, especially in special situations like pregnancy. It also
emphasizes the need for appropriate investigations in every
are the dendritic cells, studies have shown that the immunologi- case even if the diagnosis seems straight forward. Being a case
cal response in chromoblastomycosis is primarily T-cell medi- report, our findings have limitations, and we need further reports
ated. In 2003, D’Avila et al.14 suggested that patients to confirm the new findings.
presenting with verrucous plaques have Th2 immunological
response characterized by suppurative granulomas with several
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