A 47-year-old male patient presented to our hospital with multiple cutaneous nodules and ulcers on the left upper limb and the right thigh. He worked as a farmer in a rural region and had no pathological history. The lesions initially appeared 4 years ago on his middle finger of the left hand, where trauma occurred when he cut yak meat, and then, it gradually spread to the rest of his left upper limb and the right thigh. Over the past 4 years, he was hospitalized two times at a local hospital for presumed cutaneous invasive fungal infection and non-tuberculous Mycobacterium infection and had received empiric treatment with itraconazole, rifampicin, and levofloxacin for nearly 2 years with no obvious improvement. Then, the patient presented to the infection department of the West China Hospital and was hospitalized.
Blood investigations revealed an elevated erythrocyte sedimentation rate of 24 mm/h, an absolute CD3 lymphocyte count of 937 cell/mul, and an absolute CD8 lymphocyte count of 237 cell/mul. Absolute CD4 lymphocyte count, white blood cell count, and neutrophil percentage were normal. TB interferon-gamma release assay (TB-IGRA) was positive. Other blood investigations, including liver function, renal function, HIV, and viral hepatitis screening, were normal. Ultrasonography of the abdomen was also normal. Chest computed tomography (CT) revealed several sub-centimeter pulmonary nodules without lymphadenopathy. The culture of skin species for bacteria revealed Staphylococcus epidermidis, while that for fungi and mycobacteria was negative. Silver methenamine stain from biopsy tissue revealed several suspicious fungal spores. Detection of the skin tissue by the next-generation sequencing (NGS) was negative for bacteria, viruses, fungi, and mycobacteria.
Before empiric antifungal treatment, the patient was referred to the dermatology clinic for screening for cutaneous fungal infection. Physical examination revealed large scattered verrucous and ulcerated nodules with overlying necrotic eschar on the left upper limb. Further examination of the trunk and extremities revealed scattered crusted papules and plaques on the right thigh (Figure 1). After skin tissue culture for fungi was performed in the dermatology clinic, the patient was discharged and started on empiric oral voriconazole 400 mg daily. The fungal culture on sabouraud dextrose agar (SDA) at 28 C for 10 days grew into grayish-white colonies (Figure 2A). Microscopic examination with slide culture and scanning electron microscope observations of the colony indicated the morphology of Sporothrix spp. (Figures 2B,C). The strain was identified as Sporothrix globosa by calmodulin gene (CAL) sequence analysis.
Based on the aforementioned evidence, a diagnosis of cutaneous-disseminated sporotrichosis was finally established, but the patient had not shown up for follow-up but continued antifungal therapy with voriconazole at a local hospital. During a telephone follow-up, the patient reported a slow improvement after voriconazole treatment. After 8 months of antifungal treatment, the patient self-discontinued voriconazole due to financial constraints, and the lesions recurred and worsened (Figure 3). He visited our dermatology clinic again for further treatment. An antifungal susceptibility test was performed by using the E-test (BIO KONT, China), which revealed that the isolate in this case was resistant to itraconazole, fluconazole, voriconazole, terbinafine, and amphotericin. Meanwhile, considering the patient's poor financial condition, a 10% solution of potassium iodide was administered. After 1-month of therapy with potassium iodide, there was a rapid improvement in his skin lesions. He continued potassium iodide treatment for another 5 months until there was a complete resolution of lesions (Figure 4). There was no recurrence at the 6-month follow-up.