A 73-year-old male who had been receiving immunosuppressive drugs for 15 years developed a nodule on the left buttock region. The nodule slowly grew into a 15-cm fluctuant multilocular subcutaneous cyst. Serum beta-D-glucan levels were high, and the yellow purulent fluid obtained from the cyst was positive for Trichophyton rubrum. Granuloma formation in the cyst wall and large abscesses in the central cystic area were found, and septated hyphae were observed in both tissues. The cyst was surgically removed, and followed by itraconazole treatment. Notably, the clinical manifestations closely resembled those of a huge atheroma.