A 72-year-old Japanese man visited our hospital with bilateral wrist pain and swelling. The symptoms began about one month prior to his visit. Two weeks before presentation, he had consulted a local orthopedist. At the orthopedic clinic, he had bilateral wrist swelling and showed positive findings for rheumatoid factor (RF). The doctor suspected that he had RA and referred him to our hospital for further examinations.
The patient was a farmer who smoked 30 cigarettes/day for 40 years and drank alcohol occasionally. He had ulcerative colitis and had been treated with mesalazine (3.6 g/day) and prednisolone (5 mg/day); the disease was relatively well controlled. At the first visit, the patient's physical examination showed a blood pressure of 104/64 mmHg, a pulse rate of 101 beats/min, and a body temperature of 36.6 C. A musculoskeletal examination revealed marked swelling on both the dorsal and palmar surfaces of the left wrist (Fig. 1) and tenderness in both wrists. Sensation was attenuated in the palm of the left hand. Tinel's sign and Phalen's test were both positive in the left hand, indicating carpal tunnel syndrome. No skin trauma or lesions were noted. No particular findings were noted in any other systems.
Laboratory tests revealed the following: white blood cells, 9,040/mm3 (normal range, 3,500-9,000/mm3); C-reactive protein, 4.78 mg/dL (normal range, 0-0.3 mg/dL); matrix metalloproteinase-3, 199.2 ng/mL (normal range, 36.9-121 ng/mL); positive RF, 63 IU/mL (normal range, 0-15 IU/mL); negative anti-citrullinated protein antibody, 0.7 U/mL (normal range, 0-4.4 U/mL); and beta-D glucan, 9.1 pg/mL (normal range, 0-20 pg/mL). Serum urea, electrolytes, creatinine, and glucose levels were within the normal range. Wrist radiographs showed swelling of the soft tissue around the left wrist, but no bone erosions. The gray-scale image obtained from MSUS showed marked thickening of the flexor and extensor tendon sheaths in the left wrist. In addition, marked power Doppler signals were detected in the margin of the tendon sheath (Fig. 2a). The tenosynovium was filled with rice bodies (Fig. 2b). A small amount of straw-colored, cloudy synovial fluid was drained by joint-puncture from the left wrist. Neither crystals nor microorganisms were detected. Mycobacterium tuberculosis DNA was not detected by a polymerase chain reaction analysis of the synovial fluid.
Given the above clinical history and findings, he did not have typical RA and was instead suspected of having other diseases, including chronic infection. To identify the cause of the swelling in the left wrist and to relieve the carpal tunnel symptoms, we performed surgical synovectomy of the dorsal and palmar surfaces of the left wrist. Macroscopically, the extensor and flexor tendon sheaths were markedly thickened (Fig. 3a). The inside of the tendon sheaths showed marked hyperplastic synovium filled with abundant rice bodies that compressed the median nerve. In contrast, the synovia of the radiocarpal and midcarpal joints were almost intact. A histopathological examination of the resected tenosynovium revealed granulomatous tissue accompanied by plasma cell and lymphocyte infiltrations (Fig. 3b). No bacteria were found through Gram staining or Ziehl-Neelsen staining. However, Grocott's methenamine silver (GMS) stain detected a small number of oval-shaped yeasts (Fig. 4). The resected synovial tissue culture was positive for Sporothrix schenckii, and sporotrichal tenosynovitis was diagnosed.
Initially, saturated solution potassium iodide, the standard therapy for sporotrichosis, was administered. However, shortly after starting the treatment, the patient developed hypothyroidism. The treatment was promptly changed to itraconazole, an anti-fungal drug, which he continued for a total of six months without any adverse effects. Two years following completion of treatment, the patient has shown no sign of recurrence or a change in the wrist radiography findings.