Although the relationship between paracoccidioidomycosis (PCM) and solid tumors has been described more than 80 years ago, reports of PCM and gastric cancer are rare. PCM can present before or concomitantly with the diagnosis of cancer, and its clinical presentation may rise the suspicion of malignancies or be part of reactivation by immunosuppression. We present the case of a 52-year-old Peruvian man with a signet-ring cell (SRC) gastric adenocarcinoma who after 6 chemotherapy sessions with FLOT (docetaxel, oxaliplatin, leucovorin, 5-fluorouracil) presented rapidly growing lung nodules. The lung biopsy showed yeasts compatible with Paracoccidioides sp., so he received initial treatment with itraconazole and after gastrectomy maintenance therapy with trimethoprim/sulfamethoxazole accompanied by tomographic resolution of lesions.