Abstract
The patient was a 53-year-old woman who was living in a Tokyo ward and had no history of contact with soil, including gardening. However, she did have several cats, including some stray cats. An insect bite on the back of her right hand 6 months prior to the initial examination caused a rash, which was protracted and became aggravated, spreading as far as the wrist and forearm from the proximal back of the hand. In July 201X, she underwent initial examination in our department. Small to large bean-sized red nodules were distributed on the back of her right hand in a linear pattern like stepping stones. Yellow crusting had formed at the base of her index finger, and superficial erosion was observed at the back of her hand, with fusion in some areas. Several short linear scars were visible on the forearm. Mycologically, Sporothrix schenckii species complex was isolated from both the scales and biopsy tissue of the skin lesion using Sabouraud dextrose agar at 25 °C and further identified as S. globosa via genetic analysis. The histopathological examination of the nodule on the right hand revealed an irregular acanthosis, showing pseudocarcinomatous hyperplasia. Neutrophilic microabscess and granulomatous inflammatory cell infiltration in the dermis were also observed. Therefore, the patient was diagnosed with lymphatic sporotrichosis. She was administered oral potassium iodide 300 mg/day for 14-days and itraconazole 100 mg/day for 3 months, which alleviated the cutaneous lesions. The mechanism of spontaneous remission was considered during the course
The infection route may have been infection via soil adhered to a cat or zoonotic infection from an infected cat. Genetic analysis utilized in our case as well as recent domestic reports have shown S. globosa as the causative microorganism, as well as the predominant species of sporotrichosis nowadays.
