A 17-year-old male patient was admitted into our hospital with granulomatous eruption (primarily on the lower extremities), diarrhea, fever, and weight loss for 6 months. F-FDG PET/CT scan was performed to rule out the possibility of malignant metastasis or paraneoplastic syndromes. F-FDG PET/CT scan showed multiple bone and skin lesions with significantly intense FDG uptakes and lymph nodes with moderate FDG uptake. A biopsy of the skin lesions was performed, and the tissue was sent for a broad-range polymerase chain reaction amplification, which showed that the pathogenic organism was Mycobacterium avium complex.