Figure 1. An elevated pigmented mass is situated about 2.5 mm from the limbus. The leash of conjunctival vessels that surround the mass is not typical of deeper episcleral vessels (sentinel vessels) associated with a ciliary body melanoma. Inset, Irregular black surface of the mass through the epithelium, which retains some fluorescein.
Figure 2. The pigmented mass, which is separated from the epithelium, consists of a tangle of septate fungal hyphae and spherical structures (periodic acid–Schiff; bar indicates 15 μm). Inset, Spherical (or sclerotic) bodies, many of which are collapsed or weakly staining (Gomori methenamine silver; bar indicates 10 μm).
Anh Q. Bui, Edgar M. Espana, Curtis E. Margo. Chromoblastomycosis of the Conjunctiva Mimicking Melanoma of the Ciliary Body. Arch Ophthalmol. 2012;130(12):1615–1617. doi:10.1001/archophthalmol.2012.1573
Author Affiliations: Departments of Ophthalmology (Drs Bui, Espana, and Margo) and Pathology and Cell Biology (Drs Espana and Margo), Morsani College of Medicine, University of South Florida, Tampa.
Chromoblastomycosis is a chronic subcutaneous mycosis that typically involves the lower extremities. The vast majority of causative microorganisms have melanized cell walls (ie, are dematiaceous fungi) and belong to 4 genuses of saprophytic fungi: Phialophora, Fonsecaea, Rhinocladiella, and Cladophialophora.1,2 Most human infections can be traced to traumatic implantation. We describe a unique case of conjunctival chromoblastomycosis that mimicked a uveal melanoma with scleral invasion.
A 75-year-old white woman was referred for evaluation of a pigmented lesion of her right nasal conjunctiva. The lesion had been present for 16 years, following a traumatic injury with a tree branch. The initial injury was minor and required no professional medical care. A pigmented lesion, however, developed at the site of injury and enlarged slowly over years. During the last several months, it began causing irritation and redness. When examined, best-corrected visual acuity in the affected eye was 20/25. The lesion was 2.5 mm from the limbus, just thicker than 1 mm, and 3.7 mm in its greatest diameter. Under slitlamp magnification, the surface resembled black cauliflower (Figure 1). The overlying epithelium was shaggy, and it pooled and retained fluorescein (Figure 1, inset). The remainder of findings from the eye examination, including dilated ophthalmoscopy, were unremarkable. Ultrasound biomicroscopy revealed no mass beneath the lesion. Although the history of trauma was reliable, the concern over an invasive melanoma persisted, so a biopsy was recommended with that prevailing clinical diagnosis. Metastatic cutaneous melanoma was possible, although there was no history of skin melanoma. Pigmented squamous cell carcinoma and primary conjunctiva melanoma were less likely because of the location of the mass beneath the epithelium and, in the case of squamous cell carcinoma, the patient's fair complexion.
A shave biopsy was performed in the operating room. Microscopic examination showed mild epithelial hyperplasia with focal keratinization and nongranulomatous chronic inflammation of the substantia propria. The pigmented tissue consisted of tangled fungal hyphae admixed with spherical structures (Medlar bodies), measuring between 4 and 15 μm in diameter (Figure 2). The mass of fungal elements was devoid of inflammation, and hyphae showed cross septa. The Medlar bodies stained with periodic acid–Schiff reaction and Gomori methenamine silver (Figure 2, inset). No budding yeasts were seen.
Cultures from the conjunctiva were unsuccessful before the patient started treatment with topical natamycin, 5%, suspension. The patient was intolerant to topical antifungal medications and was treated with oral ketoconazole, 200 mg once daily.
The dematiaceous fungi that cause chromoblastomycosis are found worldwide, but most human infections occur in the tropics or subtropics. Organisms usually incite epithelial hyperplasia and chronic granulomatous inflammation. The chestnut-colored spherical structure known as a Medlar body (or sclerotic body) is not to be confused with conidia, or the asexual reproductive spores used to classify species under standardized growth conditions in the laboratory. Medlar bodies are poorly understood structures but are characteristic of the tissue phase of chromoblastomycosis.1- 4 They likely represent an adaptive form of dematiaceous fungus capable of surviving prolonged periods in an inhospitable environment.2,4
Although the particular fungus in this case could not be identified through microscopic examination of reproductive spores in culture, chronic mycosis of the conjunctiva of any type is exceptionally rare.5 Treatment is based on experience with cutaneous infection and consists of surgical excision and chemotherapy with a synthetic imidazole.6 Reports of late relapse with skin infection, however, are common. In the semitransparent conjunctiva, chronic infection from a dematiaceous fungus can resemble a melanocytic neoplasm and should be added to the list of pseudomelanomas of the ocular adnexa.
Correspondence: Dr Margo, Department of Ophthalmology, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd, MCD Box 21, Tampa, FL 33612 (firstname.lastname@example.org).
Conflict of Interest Disclosures: None reported.