Paracoccidioidomycosis is a disease caused by Paracoccidioides brasiliensis and Paracoccidioides lutzii. Although it is the main systemic mycosis in Brazil, it is often neglected as a diagnostic hypothesis, especially in atypical forms. To report a clinical case of bone manifestation of paracoccidioidomycosis. A 60-year-old man, a retired environmental engineer, abstinent smoker, with a history of soil exposure in rural areas, developed left iliac pain in July 2024, initially diagnosed as sciatica and treated with intramuscular betamethasone in the left gluteal region. He worsened with increased pain and unquantified weight loss, without associated fever. MRI in August showed an aggressive osteolytic lesion in the left iliac bone, with differential diagnoses including bone metastasis, multiple myeloma, and less likely an atypical infectious process. He was referred to onco-hematology and underwent outpatient biopsy, with drainage of a large amount of pus during the procedure. Histopathology revealed structures suggestive of Paracoccidioides brasiliensis, but this finding was initially disregarded, and the patient continued workup for multiple myeloma, remaining without specific treatment for two months and receiving only antibiotic cycles. In October, repeat MRI showed progression of lesions, formation of multi-septated collections in the gluteal musculature, and signs of left sacroiliitis. He underwent surgery for drainage and specimen collection; bacterial cultures were negative, and biopsy confirmed fungal granulomas and the presence of P. brasiliensis. He started itraconazole 200 mg/day in November and began follow-up with infectious diseases. HIV serology was negative and chest radiography showed no abnormalities. In December, another surgical debridement was performed with good evolution. Since then, he has remained on itraconazole, with resolution of pain and 10 kg weight regain. Although rare, bone involvement in paracoccidioidomycosis can occur and should be considered in the differential diagnosis of osteolytic lesions, especially when there is a history of exposure to rural or endemic areas.
Bobrovski et al. (2026) studied this question.