Li-Fraumeni syndrome and Birt-Hogg-Dubé syndrome are distinct cancer predisposition syndromes caused by germline pathogenic variants (GPVs) in TP53 and FLCN, respectively. Multilocus inherited neoplasia alleles syndrome (MINAS) describes the co-occurrence of GPVs in two or more cancer predisposition genes. We present a unique case of a boy aged 16 years with multiple, very early onset atypical cutaneous fibrous histiocytomas (ACFHs), diagnosed with MINAS due to de novo TP53 and paternally inherited FLCN GPVs. This case is the first reported association of ACFH with germline TP53 and FLCN pathogenic variants. This paper highlights the importance of considering MINAS in patients with unusual tumour presentations. We discuss the clinical, histopathological and genetic findings, emphasising the need for comprehensive genetic testing and personalised surveillance in such cases.