Objective: Cryptococcus, a genus of fungi, primarily includes Cryptococcus neoformans and Cryptococcus gattii, both known to cause human infections. Skeletal infections are rare, and there have been no reported cases of bone cryptococcal infection in conjunction with differentiated thyroid carcinoma.
Subject and methods: A 56-year-old female presented with a one-month history of "cough and throat irritation." Chest CT revealed scattered small nodules in both lungs,suggestive of metastasis.There was minimal inflammation in both lungs, and scattered lymph nodes were observed in the mediastinum and upper pulmonary hilum.
Results: The patient was diagnosed with differentiated thyroid carcinoma complicated by cryptococcal infection. Antifungal treatment with itraconazole 200mg/day was initiated, and after 3 months, clinical symptoms disappeared, with a reduction in lung nodules observed in follow-up chest CT.
Conclusion: When diagnosing distant metastasis in differentiated thyroid carcinoma, a comprehensive analysis combining imaging studies and serum thyroid globulin plays a complementary role, as illustrated in this case of differentiated thyroid carcinoma concurrent with cryptococcal infection.