Here, we present a case with a malignant, metastatic perivascular epithelioid cell tumor (PEComa) of the thigh muscle and a sinonasal carcinoma harboring a novel <i>TP53</i> germline splice mutation (NM_000546.5:c.97-2A>C). The gene discussed is TP53; the disease is nasal cavity and paranasal sinus carcinoma.