|Year : 2014 | Volume
| Issue : 2 | Page : 199-201
An unusual finding in a subcutaneous cyst: A case of phaeohyphomycotic cyst
Prema C Saldanha1, Vidya Pai2
1 Department of Pathology, Yenepoya Medical College, Mangalore, Karnataka, India
2 Department of Microbiology, Yenepoya Medical College, Mangalore, Karnataka, India
|Date of Web Publication||11-Nov-2014|
Department of Microbiology, Yenepoya Medical College, Mangalore - 575 018, Karnataka
Source of Support: None, Conflict of Interest: None
Phaeohyphomycosis is a mycotic infection, which can be caused by different fungal organisms commonly presenting as cutaneous and subcutaneous cysts. The diagnosis can only be made by histopathological examination, and the entity should be considered in the clinical differential diagnosis of every cystic lesion of the skin.
Keywords: Cystic, phaeohyphomycosis, subcutaneous
|How to cite this article:|
Saldanha PC, Pai V. An unusual finding in a subcutaneous cyst: A case of phaeohyphomycotic cyst. Arch Med Health Sci 2014;2:199-201
| Introduction|| |
Phaeohyphomycosis is fungal infection caused by a number of phaeoid, dematiaceous, or melanized fungi. It is characterized by the presence of darkly-colored filamentous hyphae in the invaded tissue.  It is a disease caused by many different fungal organisms with multiple clinical presentations. , This case is being reported as it was not suspected clinically, and the diagnosis was made only after histopathological examination.
| Case Report|| |
A 50-year-old man presented with a swelling on the dorsal aspect of the left ankle, which was present since 4 years. He developed pain since 2 months. The patient's occupation was indoors, and no history of trauma was present. The patient was not immunocompromised. On examination, the swelling was tender, but there were no other signs of inflammation. The swelling was cystic in consistency. The lesion was clinically diagnosed as a sebaceous cyst and was excised. The excised cystic mass measured 6 × 4 × 3 cms and on cut section, was unilocular, with a thick cyst wall, and was filled with pultaceous material, which looked typical of keratinous material seen in a sebaceous cyst. Histopathological examination showed a fibrocollagenous wall lined by sheets of foamy macrophages, neutrophils, lymphocytes, and foreign-body type giant cells. In foci, necrotic material containing fungal hyphae was seen. The hyphae were septate with irregular branches at acute angles and constrictions close to the septae. Yeast-like oval cells were also seen [Figure 1] and [Figure 2]. Some of the hyphae were seen within the giant cells. The fungus was easily seen in the Hematoxylin and Eosin [H and E] sections and confirmed by Periodic Acid Schiff (PAS) stain. A diagnosis of phaeohyphomycotic cyst was made. It was not possible to culture the fungus for species identification as the material was already fixed in formalin.
|Figure 2: Section showing septate hyphae with irregular branches at acute angles, PAS stain|
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| Discussion|| |
The term Phaeohyphomycosis was first proposed by Ajello et al. in 1974. The term encompasses these distinct mycotic infections regardless of the site of the lesion, the pattern of tissue response, or the taxonomic classification of the etiological agents.  The most common and typical lesions are cutaneous and subcutaneous cysts resembling sebaceous cysts or abscesses. The lesion occurs as a single, discrete, asymptomatic small nodule, which is palpable as a smooth swelling, especially common on the extremities. , Subcutaneous phaeohyphomycosis occurs throughout the world in all climates. A few cases have also been reported from India. ,, They are saprophytes and occur in soil, decaying wood, and vegetation. Phialophora species are the most frequently isolated fungi. They have low virulence and low pathogenicity. Infection is usually as a result of traumatic implantation. In this case, there was no history of trauma, but the trauma could have been so trivial and not noticed by the patient as it was in the ankle region. On gross examination, the cyst was filled with pultaceous material, which looked typical of cheesy keratinous material seen in a sebaceous cyst, hence not suspected at the macroscopically. Histopathologically, the features of the cyst were consistent with a pseudocyst caused by the fungus. There was no histopathological evidence of a cyst lining or evidence to suggest the origin of the cyst.
The cystic type is caused by Phialophora gourgerotti [Exophiala jeanselmei]. ,,, The hyphae have irregularly placed branches and show constrictions around the septae, that may cause them to resemble pseudohyphae, but true yeast forms are not seen. Pigment is not always obvious. The hyphae of Aspergillus have relatively uniform diameter, and regular dichotomous branching spores are absent. Alternariosis shows broad, branching, brown septate hyphae and large, round to oval often doubly contoured spores. Chromoblastomycosis shows thick-walled phaeoid, muriform cells. Mycetoma is characterized by the presence of sinuses discharging black granules, which was not found in this case. Microscopically, the hyphae are thick and septate. ,, The morphology of the fungus on histopathology was useful to make a diagnosis of phaeohyphomycosis in this case.
The disease may be cured by surgical excision. However, in recurrent cases, antifungal treatment may be required. Culture of all cystic swellings is not mandatory. A detailed histopathological examination is sufficient in most cases to identify the fungus.
| Conclusion|| |
This case emphasizes the importance of considering phaeohyphomycotic cysts in the differential diagnosis of subcutaneous cystic nodules, especially on the extremities.
| References|| |
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[Figure 1], [Figure 2]